ROPER, SUPERINTENDENT, POTOSI CORREC- TIONAL CENTER v. SIMMONS

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551 OCTOBER TERM, 2004
Syllabus
ROPER, SUPERINTENDENT, POTOSI CORREC-
TIONAL CENTER v. SIMMONS
certiorari to the supreme court of missouri
No. 03–633. Argued October 13, 2004—Decided March 1, 2005
At age 17, respondent Simmons planned and committed a capital murder.
After he had turned 18, he was sentenced to death. His direct appeal
and subsequent petitions for state and federal postconviction relief were
rejected. This Court then held, in Atkins v. Virginia, 536 U. S. 304,
that the Eighth Amendment, applicable to the States through the Four-
teenth Amendment, prohibits the execution of a mentally retarded per-
son. Simmons filed a new petition for state postconviction relief,
arguing that Atkins’ reasoning established that the Constitution prohib-
its the execution of a juvenile who was under 18 when he committed his
crime. The Missouri Supreme Court agreed and set aside Simmons’
death sentence in favor of life imprisonment without eligibility for re-
lease. It held that, although Stanford v. Kentucky, 492 U. S. 361,
rejected the proposition that the Constitution bars capital punishment
for juvenile offenders younger than 18, a national consensus has devel-
oped against the execution of those offenders since Stanford.
Held: The Eighth and Fourteenth Amendments forbid imposition of the
death penalty on offenders who were under the age of 18 when their
crimes were committed. Pp. 560–579.
(a) The Eighth Amendment’s prohibition against “cruel and unusual
punishments” must be interpreted according to its text, by considering
history, tradition, and precedent, and with due regard for its purpose
and function in the constitutional design. To implement this framework
this Court has established the propriety and affirmed the necessity of
referring to “the evolving standards of decency that mark the progress
of a maturing society” to determine which punishments are so dispro-
portionate as to be “cruel and unusual.” Trop v. Dulles, 356 U. S. 86,
100–101. In 1988, in Thompson v. Oklahoma, 487 U. S. 815, 818–838, a
plurality determined that national standards of decency did not permit
the execution of any offender under age 16 at the time of the crime.
The next year, in Stanford, a 5-to-4 Court referred to contemporary
standards of decency, but concluded the Eighth and Fourteenth Amend-
ments did not proscribe the execution of offenders over 15 but under 18
because 22 of 37 death penalty States permitted that penalty for 16-
year-old offenders, and 25 permitted it for 17-year-olds, thereby indicat-
ing there was no national consensus. 492 U. S., at 370–371. A plural-

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552 ROPER v. SIMMONS
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ity also “emphatically reject[ed]” the suggestion that the Court should
bring its own judgment to bear on the acceptability of the juvenile death
penalty. Id., at 377–378. That same day the Court held, in Penry v.
Lynaugh, 492 U. S. 302, 334, that the Eighth Amendment did not man-
date a categorical exemption from the death penalty for mentally re-
tarded persons because only two States had enacted laws banning such
executions. Three Terms ago in Atkins, however, the Court held that
standards of decency had evolved since Penry and now demonstrated
that the execution of the mentally retarded is cruel and unusual punish-
ment. The Atkins Court noted that objective indicia of society’s stand-
ards, as expressed in pertinent legislative enactments and state prac-
tice, demonstrated that such executions had become so truly unusual
that it was fair to say that a national consensus has developed against
them. 536 U. S., at 314–315. The Court also returned to the rule, es-
tablished in decisions predating Stanford, that the Constitution contem-
plates that the Court’s own judgment be brought to bear on the question
of the acceptability of the death penalty. 536 U. S., at 312. After ob-
serving that mental retardation diminishes personal culpability even if
the offender can distinguish right from wrong, id., at 318, and that men-
tally retarded offenders’ impairments make it less defensible to impose
the death penalty as retribution for past crimes or as a real deterrent
to future crimes, id., at 319–320, the Court ruled that the death penalty
constitutes an excessive sanction for the entire category of mentally
retarded offenders, and that the Eighth Amendment places a substan-
tive restriction on the State’s power to take such an offender’s life,
id., at 321. Just as the Atkins Court reconsidered the issue decided
in Penry, the Court now reconsiders the issue decided in Stanford.
Pp. 560–564.
(b) Both objective indicia of consensus, as expressed in particular by
the enactments of legislatures that have addressed the question, and the
Court’s own determination in the exercise of its independent judgment,
demonstrate that the death penalty is a disproportionate punishment
for juveniles. Pp. 564–575.
(1) As in Atkins, the objective indicia of national consensus here—
the rejection of the juvenile death penalty in the majority of States;
the infrequency of its use even where it remains on the books; and the
consistency in the trend toward abolition of the practice—provide suffi-
cient evidence that today society views juveniles, in the words Atkins
used respecting the mentally retarded, as “categorically less culpable
than the average criminal,” 536 U. S., at 316. The evidence of such
consensus is similar, and in some respects parallel, to the evidence in
Atkins: 30 States prohibit the juvenile death penalty, including 12 that
have rejected it altogether and 18 that maintain it but, by express provi-

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553 Cite as: 543 U. S. 551 (2005)
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sion or judicial interpretation, exclude juveniles from its reach. More-
over, even in the 20 States without a formal prohibition, the execution
of juveniles is infrequent. Although, by contrast to Atkins, the rate of
change in reducing the incidence of the juvenile death penalty, or in
taking specific steps to abolish it, has been less dramatic, the difference
between this case and Atkins in that respect is counterbalanced by the
consistent direction of the change toward abolition. Indeed, the slower
pace here may be explained by the simple fact that the impropriety of
executing juveniles between 16 and 18 years old gained wide recogni-
tion earlier than the impropriety of executing the mentally retarded.
Pp. 564–567.
(2) Rejection of the imposition of the death penalty on juvenile of-
fenders under 18 is required by the Eighth Amendment. Capital pun-
ishment must be limited to those offenders who commit “a narrow
category of the most serious crimes” and whose extreme culpability
makes them “the most deserving of execution.” Atkins, supra, at 319.
Three general differences between juveniles under 18 and adults demon-
strate that juvenile offenders cannot with reliability be classified among
the worst offenders. Juveniles’ susceptibility to immature and irre-
sponsible behavior means “their irresponsible conduct is not as morally
reprehensible as that of an adult.” Thompson v. Oklahoma, 487 U. S.
815, 835. Their own vulnerability and comparative lack of control over
their immediate surroundings mean juveniles have a greater claim than
adults to be forgiven for failing to escape negative influences in their
whole environment. See Stanford, supra, at 395. The reality that ju-
veniles still struggle to define their identity means it is less supportable
to conclude that even a heinous crime committed by a juvenile is evi-
dence of irretrievably depraved character. The Thompson plurality
recognized the import of these characteristics with respect to juveniles
under 16. 487 U. S., at 833–838. The same reasoning applies to all
juvenile offenders under 18. Once juveniles’ diminished culpability is
recognized, it is evident that neither of the two penological justifications
for the death penalty—retribution and deterrence of capital crimes by
prospective offenders, e. g., Atkins, supra, at 319—provides adequate
justification for imposing that penalty on juveniles. Although the
Court cannot deny or overlook the brutal crimes too many juvenile of-
fenders have committed, it disagrees with petitioner’s contention that,
given the Court’s own insistence on individualized consideration in capi-
tal sentencing, it is arbitrary and unnecessary to adopt a categorical
rule barring imposition of the death penalty on an offender under 18.
An unacceptable likelihood exists that the brutality or cold-blooded na-
ture of any particular crime would overpower mitigating arguments
based on youth as a matter of course, even where the juvenile offender’s

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554 ROPER v. SIMMONS
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objective immaturity, vulnerability, and lack of true depravity should
require a sentence less severe than death. When a juvenile commits a
heinous crime, the State can exact forfeiture of some of the most basic
liberties, but the State cannot extinguish his life and his potential to
attain a mature understanding of his own humanity. While drawing
the line at 18 is subject to the objections always raised against categori-
cal rules, that is the point where society draws the line for many pur-
poses between childhood and adulthood and the age at which the line for
death eligibility ought to rest. Stanford should be deemed no longer
controlling on this issue. Pp. 568–575.
(c) The overwhelming weight of international opinion against the ju-
venile death penalty is not controlling here, but provides respected and
significant confirmation for the Court’s determination that the penalty
is disproportionate punishment for offenders under 18. See, e. g.,
Thompson, supra, at 830–831, and n. 31. The United States is the only
country in the world that continues to give official sanction to the juve-
nile penalty. It does not lessen fidelity to the Constitution or pride
in its origins to acknowledge that the express affirmation of certain
fundamental rights by other nations and peoples underscores the cen-
trality of those same rights within our own heritage of freedom.
Pp. 575–578.
112 S. W. 3d 397, affirmed.
Kennedy, J., delivered the opinion of the Court, in which Stevens,
Souter, Ginsburg, and Breyer, JJ., joined. Stevens, J., filed a concur-
ring opinion, in which Ginsburg, J., joined, post, p. 587. O’Connor, J.,
filed a dissenting opinion, post, p. 587. Scalia, J., filed a dissenting opin-
ion, in which Rehnquist, C. J., and Thomas, J., joined, post, p. 607.
James R. Layton, State Solicitor of Missouri, argued the
cause for petitioner. With him on the briefs were Jeremiah
W. (Jay) Nixon, Attorney General, and Stephen D. Hawke
and Evan J. Buchheim, Assistant Attorneys General.
Seth P. Waxman argued the cause for respondent. With
him on the brief were David W. Ogden and Jennifer Hern-
don, by appointment of the Court, 541 U. S. 1040.*
*A brief of amici curiae urging reversal was filed for the State of Ala-
bama et al. by Troy King, Attorney General of Alabama, Kevin C. New-
som, Solicitor General, and A. Vernon Barnett IV, Deputy Solicitor Gen-
eral, and by the Attorneys General for their respective States as follows:
M. Jane Brady of Delaware, W. A. Drew Edmondson of Oklahoma, Greg

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555 Cite as: 543 U. S. 551 (2005)
Opinion of the Court
Justice Kennedy delivered the opinion of the Court.
This case requires us to address, for the second time in a
decade and a half, whether it is permissible under the Eighth
and Fourteenth Amendments to the Constitution of the
United States to execute a juvenile offender who was older
Abbott of Texas, Mark L. Shurtleff of Utah, and Jerry W. Kilgore of
Virginia.
Briefs of amici curiae urging affirmance were filed for the State of New
York et al. by Eliot Spitzer, Attorney General of New York, Caitlin J.
Halligan, Solicitor General, Daniel Smirlock, Deputy Solicitor General,
and Jean Lin and Julie Loughran, Assistant Solicitors General, and by
the Attorneys General for their respective States as follows: Thomas J.
Miller of Iowa, Phill Kline of Kansas, J. Joseph Curran, Jr., of Maryland,
Mike Hatch of Minnesota, Patricia A. Madrid of New Mexico, Hardy
Myers of Oregon, and Darrell V. McGraw, Jr., of West Virginia; for the
American Bar Association by Dennis W. Archer, Amy R. Sabrin, and Mat-
thew W. S. Estes; for the American Psychological Association et al. by
Drew S. Days III, Beth S. Brinkmann, Sherri N. Blount, Timothy C.
Lambert, Nathalie F. P. Gilfoyle, and Lindsay Childress-Beatty; for the
Coalition for Juvenile Justice by Joseph D. Tydings; for the Constitution
Project by Laurie Webb Daniel and Virginia E. Sloan; for the Human
Rights Committee of the Bar of England and Wales et al. by Michael
Bochenek, Audrey J. Anderson, William H. Johnson, and Thomas H.
Speedy Rice; for the Juvenile Law Center et al. by Marsha L. Levick,
Lourdes M. Rosado, Steven A. Drizin, Barbara Bennett Woodhouse, Mi-
chael C. Small, and Jeffrey P. Kehne; for the Missouri Ban Youth Execu-
tions Coalition by Joseph W. Luby; for the NAACP Legal Defense and
Educational Fund, Inc., et al. by Theodore M. Shaw, Norman J. Chachkin,
Miriam Gohara, Christina A. Swarns, Steven R. Shapiro, and Diann Y.
Rust-Tierney; for the United States Conference of Catholic Bishops et al.
by Mark E. Chopko and Michael F. Moses; and for Former U. S. Diplomats
Morton Abramowitz et al. by Harold Hongju Koh, Donald Francis Dono-
van, and Stephen B. Bright.
Briefs of amici curiae were filed for the European Union et al. by Rich-
ard J. Wilson; for the American Medical Association et al. by Joseph T.
McLaughlin, E. Joshua Rosenkranz, and Stephane M. Clare; for the Jus-
tice for All Alliance by Dan Cutrer; for Murder Victims’ Families for Rec-
onciliation by Kate Lowenstein; for the National Legal Aid and Defender
Association by Michael Mello; and for President James Earl Carter, Jr.,
et al. by Thomas F. Geraghty.

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556 ROPER v. SIMMONS
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than 15 but younger than 18 when he committed a capital
crime. In Stanford v. Kentucky, 492 U. S. 361 (1989), a di-
vided Court rejected the proposition that the Constitution
bars capital punishment for juvenile offenders in this age
group. We reconsider the question.
I
At the age of 17, when he was still a junior in high school,
Christopher Simmons, the respondent here, committed mur-
der. About nine months later, after he had turned 18, he
was tried and sentenced to death. There is little doubt that
Simmons was the instigator of the crime. Before its com-
mission Simmons said he wanted to murder someone. In
chilling, callous terms he talked about his plan, discussing it
for the most part with two friends, Charles Benjamin and
John Tessmer, then aged 15 and 16 respectively. Simmons
proposed to commit burglary and murder by breaking and
entering, tying up a victim, and throwing the victim off a
bridge. Simmons assured his friends they could “get away
with it” because they were minors.
The three met at about 2 a.m. on the night of the murder,
but Tessmer left before the other two set out. (The State
later charged Tessmer with conspiracy, but dropped the
charge in exchange for his testimony against Simmons.)
Simmons and Benjamin entered the home of the victim, Shir-
ley Crook, after reaching through an open window and un-
locking the back door. Simmons turned on a hallway light.
Awakened, Mrs. Crook called out, “Who’s there?” In re-
sponse Simmons entered Mrs. Crook’s bedroom, where he
recognized her from a previous car accident involving them
both. Simmons later admitted this confirmed his resolve
to murder her.
Using duct tape to cover her eyes and mouth and bind her
hands, the two perpetrators put Mrs. Crook in her minivan
and drove to a state park. They reinforced the bindings,
covered her head with a towel, and walked her to a rail-

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road trestle spanning the Meramec River. There they tied
her hands and feet together with electrical wire, wrapped
her whole face in duct tape and threw her from the bridge,
drowning her in the waters below.
By the afternoon of September 9, Steven Crook had re-
turned home from an overnight trip, found his bedroom in
disarray, and reported his wife missing. On the same after-
noon fishermen recovered the victim’s body from the river.
Simmons, meanwhile, was bragging about the killing, telling
friends he had killed a woman “because the bitch seen my
face.”
The next day, after receiving information of Simmons’
involvement, police arrested him at his high school and took
him to the police station in Fenton, Missouri. They read
him his Miranda rights. Simmons waived his right to an
attorney and agreed to answer questions. After less than
two hours of interrogation, Simmons confessed to the murder
and agreed to perform a videotaped reenactment at the
crime scene.
The State charged Simmons with burglary, kidnaping,
stealing, and murder in the first degree. As Simmons was
17 at the time of the crime, he was outside the criminal juris-
diction of Missouri’s juvenile court system. See Mo. Rev.
Stat. §§ 211.021 (2000) and 211.031 (Supp. 2003). He was
tried as an adult. At trial the State introduced Simmons’
confession and the videotaped reenactment of the crime,
along with testimony that Simmons discussed the crime in
advance and bragged about it later. The defense called no
witnesses in the guilt phase. The jury having returned a
verdict of murder, the trial proceeded to the penalty phase.
The State sought the death penalty. As aggravating fac-
tors, the State submitted that the murder was committed for
the purpose of receiving money; was committed for the pur-
pose of avoiding, interfering with, or preventing lawful ar-
rest of the defendant; and involved depravity of mind and
was outrageously and wantonly vile, horrible, and inhuman.

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The State called Shirley Crook’s husband, daughter, and two
sisters, who presented moving evidence of the devastation
her death had brought to their lives.
In mitigation Simmons’ attorneys first called an officer of
the Missouri juvenile justice system, who testified that Sim-
mons had no prior convictions and that no previous charges
had been filed against him. Simmons’ mother, father, two
younger half brothers, a neighbor, and a friend took the
stand to tell the jurors of the close relationships they had
formed with Simmons and to plead for mercy on his behalf.
Simmons’ mother, in particular, testified to the responsibility
Simmons demonstrated in taking care of his two younger
half brothers and of his grandmother and to his capacity to
show love for them.
During closing arguments, both the prosecutor and de-
fense counsel addressed Simmons’ age, which the trial judge
had instructed the jurors they could consider as a mitigating
factor. Defense counsel reminded the jurors that juveniles
of Simmons’ age cannot drink, serve on juries, or even see
certain movies, because “the legislatures have wisely de-
cided that individuals of a certain age aren’t responsible
enough.” Defense counsel argued that Simmons’ age should
make “a huge difference to [the jurors] in deciding just ex-
actly what sort of punishment to make.” In rebuttal, the
prosecutor gave the following response: “Age, he says.
Think about age. Seventeen years old. Isn’t that scary?
Doesn’t that scare you? Mitigating? Quite the contrary I
submit. Quite the contrary.”
The jury recommended the death penalty after finding the
State had proved each of the three aggravating factors sub-
mitted to it. Accepting the jury’s recommendation, the trial
judge imposed the death penalty.
Simmons obtained new counsel, who moved in the trial
court to set aside the conviction and sentence. One argu-
ment was that Simmons had received ineffective assistance
at trial. To support this contention, the new counsel called

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as witnesses Simmons’ trial attorney, Simmons’ friends and
neighbors, and clinical psychologists who had evaluated him.
Part of the submission was that Simmons was “very imma-
ture,” “very impulsive,” and “very susceptible to being ma-
nipulated or influenced.” The experts testified about Sim-
mons’ background including a difficult home environment and
dramatic changes in behavior, accompanied by poor school
performance in adolescence. Simmons was absent from
home for long periods, spending time using alcohol and drugs
with other teenagers or young adults. The contention by
Simmons’ postconviction counsel was that these matters
should have been established in the sentencing proceeding.
The trial court found no constitutional violation by reason
of ineffective assistance of counsel and denied the motion for
postconviction relief. In a consolidated appeal from Sim-
mons’ conviction and sentence, and from the denial of post-
conviction relief, the Missouri Supreme Court affirmed.
State v. Simmons, 944 S. W. 2d 165, 169 (en banc), cert. de-
nied, 522 U. S. 953 (1997). The federal courts denied Sim-
mons’ petition for a writ of habeas corpus. Simmons v.
Bowersox, 235 F. 3d 1124, 1127 (CA8), cert. denied, 534 U. S.
924 (2001).
After these proceedings in Simmons’ case had run their
course, this Court held that the Eighth and Fourteenth
Amendments prohibit the execution of a mentally retarded
person. Atkins v. Virginia, 536 U. S. 304 (2002). Simmons
filed a new petition for state postconviction relief, arguing
that the reasoning of Atkins established that the Constitu-
tion prohibits the execution of a juvenile who was under 18
when the crime was committed.
The Missouri Supreme Court agreed. State ex rel. Sim-
mons v. Roper, 112 S. W. 3d 397 (2003) (en banc). It held
that since Stanford,
“a national consensus has developed against the execu-
tion of juvenile offenders, as demonstrated by the fact
that eighteen states now bar such executions for juve-

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niles, that twelve other states bar executions altogether,
that no state has lowered its age of execution below 18
since Stanford, that five states have legislatively or by
case law raised or established the minimum age at 18,
and that the imposition of the juvenile death penalty has
become truly unusual over the last decade.” 112 S. W.
3d, at 399.
On this reasoning it set aside Simmons’ death sentence and
resentenced him to “life imprisonment without eligibility for
probation, parole, or release except by act of the Governor.”
Id., at 413.
We granted certiorari, 540 U. S. 1160 (2004), and now
affirm.
II
The Eighth Amendment provides: “Excessive bail shall
not be required, nor excessive fines imposed, nor cruel and
unusual punishments inflicted.” The provision is applicable
to the States through the Fourteenth Amendment. Fur-
man v. Georgia, 408 U. S. 238, 239 (1972) (per curiam); Rob-
inson v. California, 370 U. S. 660, 666–667 (1962); Louisiana
ex rel. Francis v. Resweber, 329 U. S. 459, 463 (1947) (plural-
ity opinion). As the Court explained in Atkins, the Eighth
Amendment guarantees individuals the right not to be sub-
jected to excessive sanctions. The right flows from the
basic “ ‘precept of justice that punishment for crime should
be graduated and proportioned to [the] offense.’ ” 536 U. S.,
at 311 (quoting Weems v. United States, 217 U. S. 349, 367
(1910)). By protecting even those convicted of heinous
crimes, the Eighth Amendment reaffirms the duty of the
government to respect the dignity of all persons.
The prohibition against “cruel and unusual punishments,”
like other expansive language in the Constitution, must be
interpreted according to its text, by considering history, tra-
dition, and precedent, and with due regard for its purpose
and function in the constitutional design. To implement this

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framework we have established the propriety and affirmed
the necessity of referring to “the evolving standards of de-
cency that mark the progress of a maturing society” to deter-
mine which punishments are so disproportionate as to be
cruel and unusual. Trop v. Dulles, 356 U. S. 86, 100–101
(1958) (plurality opinion).
In Thompson v. Oklahoma, 487 U. S. 815 (1988), a plurality
of the Court determined that our standards of decency do
not permit the execution of any offender under the age of 16
at the time of the crime. Id., at 818–838 (opinion of Ste-
vens, J., joined by Brennan, Marshall, and Blackmun, JJ.).
The plurality opinion explained that no death penalty State
that had given express consideration to a minimum age for
the death penalty had set the age lower than 16. Id., at
826–829. The plurality also observed that “[t]he conclusion
that it would offend civilized standards of decency to execute
a person who was less than 16 years old at the time of his
or her offense is consistent with the views that have been
expressed by respected professional organizations, by other
nations that share our Anglo-American heritage, and by the
leading members of the Western European community.”
Id., at 830. The opinion further noted that juries imposed
the death penalty on offenders under 16 with exceeding rar-
ity; the last execution of an offender for a crime committed
under the age of 16 had been carried out in 1948, 40 years
prior. Id., at 832–833.
Bringing its independent judgment to bear on the permis-
sibility of the death penalty for a 15-year-old offender, the
Thompson plurality stressed that “[t]he reasons why juve-
niles are not trusted with the privileges and responsibilities
of an adult also explain why their irresponsible conduct is
not as morally reprehensible as that of an adult.” Id., at
835. According to the plurality, the lesser culpability of of-
fenders under 16 made the death penalty inappropriate as a
form of retribution, while the low likelihood that offenders
under 16 engaged in “the kind of cost-benefit analysis that

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attaches any weight to the possibility of execution” made the
death penalty ineffective as a means of deterrence. Id., at
836–838. With Justice O’Connor concurring in the judg-
ment on narrower grounds, id., at 848–859, the Court set
aside the death sentence that had been imposed on the 15-
year-old offender.
The next year, in Stanford v. Kentucky, 492 U. S. 361
(1989), the Court, over a dissenting opinion joined by four
Justices, referred to contemporary standards of decency in
this country and concluded the Eighth and Fourteenth
Amendments did not proscribe the execution of juvenile of-
fenders over 15 but under 18. The Court noted that 22 of
the 37 death penalty States permitted the death penalty for
16-year-old offenders, and, among these 37 States, 25 permit-
ted it for 17-year-old offenders. These numbers, in the
Court’s view, indicated there was no national consensus “suf-
ficient to label a particular punishment cruel and unusual.”
Id., at 370–371. A plurality of the Court also “emphatically
reject[ed]” the suggestion that the Court should bring its
own judgment to bear on the acceptability of the juvenile
death penalty. Id., at 377–378 (opinion of Scalia, J., joined
by Rehnquist, C. J., and White and Kennedy, JJ.); see also
id., at 382 (O’Connor, J., concurring in part and concurring
in judgment) (criticizing the plurality’s refusal “to judge
whether the ‘ “nexus between the punishment imposed and
the defendant’s blameworthiness” ’ is proportional”).
The same day the Court decided Stanford, it held that the
Eighth Amendment did not mandate a categorical exemption
from the death penalty for the mentally retarded. Penry v.
Lynaugh, 492 U. S. 302 (1989). In reaching this conclusion
it stressed that only two States had enacted laws banning
the imposition of the death penalty on a mentally retarded
person convicted of a capital offense. Id., at 334. Accord-
ing to the Court, “the two state statutes prohibiting execu-
tion of the mentally retarded, even when added to the 14
States that have rejected capital punishment completely,

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[did] not provide sufficient evidence at present of a national
consensus.” Ibid.
Three Terms ago the subject was reconsidered in Atkins.
We held that standards of decency have evolved since Penry
and now demonstrate that the execution of the mentally re-
tarded is cruel and unusual punishment. The Court noted
objective indicia of society’s standards, as expressed in legis-
lative enactments and state practice with respect to execu-
tions of the mentally retarded. When Atkins was decided
only a minority of States permitted the practice, and even in
those States it was rare. 536 U. S., at 314–315. On the
basis of these indicia the Court determined that executing
mentally retarded offenders “has become truly unusual, and
it is fair to say that a national consensus has developed
against it.” Id., at 316.
The inquiry into our society’s evolving standards of de-
cency did not end there. The Atkins Court neither repeated
nor relied upon the statement in Stanford that the Court’s
independent judgment has no bearing on the acceptability
of a particular punishment under the Eighth Amendment.
Instead we returned to the rule, established in decisions pre-
dating Stanford, that “ ‘the Constitution contemplates that
in the end our own judgment will be brought to bear on the
question of the acceptability of the death penalty under the
Eighth Amendment.’ ” 536 U. S., at 312 (quoting Coker v.
Georgia, 433 U. S. 584, 597 (1977) (plurality opinion)). Men-
tal retardation, the Court said, diminishes personal culpabil-
ity even if the offender can distinguish right from wrong.
536 U. S., at 318. The impairments of mentally retarded of-
fenders make it less defensible to impose the death penalty
as retribution for past crimes and less likely that the death
penalty will have a real deterrent effect. Id., at 319–320.
Based on these considerations and on the finding of national
consensus against executing the mentally retarded, the
Court ruled that the death penalty constitutes an excessive
sanction for the entire category of mentally retarded offend-

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ers, and that the Eighth Amendment “ ‘places a substantive
restriction on the State’s power to take the life’ of a mentally
retarded offender.” Id., at 321 (quoting Ford v. Wainwright,
477 U. S. 399, 405 (1986)).
Just as the Atkins Court reconsidered the issue decided in
Penry, we now reconsider the issue decided in Stanford.
The beginning point is a review of objective indicia of con-
sensus, as expressed in particular by the enactments of legis-
latures that have addressed the question. These data give
us essential instruction. We then must determine, in the
exercise of our own independent judgment, whether the
death penalty is a disproportionate punishment for juveniles.
III
A
The evidence of national consensus against the death pen-
alty for juveniles is similar, and in some respects parallel, to
the evidence Atkins held sufficient to demonstrate a national
consensus against the death penalty for the mentally re-
tarded. When Atkins was decided, 30 States prohibited the
death penalty for the mentally retarded. This number com-
prised 12 that had abandoned the death penalty altogether,
and 18 that maintained it but excluded the mentally retarded
from its reach. 536 U. S., at 313–315. By a similar calcula-
tion in this case, 30 States prohibit the juvenile death pen-
alty, comprising 12 that have rejected the death penalty alto-
gether and 18 that maintain it but, by express provision or
judicial interpretation, exclude juveniles from its reach.
See Appendix A, infra. Atkins emphasized that even in the
20 States without formal prohibition, the practice of execut-
ing the mentally retarded was infrequent. Since Penry,
only five States had executed offenders known to have an IQ
under 70. 536 U. S., at 316. In the present case, too, even
in the 20 States without a formal prohibition on executing
juveniles, the practice is infrequent. Since Stanford, six
States have executed prisoners for crimes committed as ju-

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veniles. In the past 10 years, only three have done so: Okla-
homa, Texas, and Virginia. See V. Streib, The Juvenile
Death Penalty Today: Death Sentences and Executions for
Juvenile Crimes, January 1, 1973–December 31, 2004, No. 76,
p. 4 (2005), available at http://www.law.onu.edu/faculty/streib/
documents/JuvDeathDec2004.pdf (last updated Jan. 31, 2005)
(as visited Feb. 25, 2005, and available in Clerk of Court’s
case file). In December 2003 the Governor of Kentucky de-
cided to spare the life of Kevin Stanford, and commuted his
sentence to one of life imprisonment without parole, with the
declaration that “ ‘[w]e ought not be executing people who,
legally, were children.’ ” Lexington Herald Leader, Dec. 9,
2003, p. B3, 2003 WL 65043346. By this act the Governor
ensured Kentucky would not add itself to the list of States
that have executed juveniles within the last 10 years even
by the execution of the very defendant whose death sentence
the Court had upheld in Stanford v. Kentucky.
There is, to be sure, at least one difference between the
evidence of consensus in Atkins and in this case. Impres-
sive in Atkins was the rate of abolition of the death penalty
for the mentally retarded. Sixteen States that permitted
the execution of the mentally retarded at the time of Penry
had prohibited the practice by the time we heard Atkins.
By contrast, the rate of change in reducing the incidence of
the juvenile death penalty, or in taking specific steps to abol-
ish it, has been slower. Five States that allowed the juve-
nile death penalty at the time of Stanford have abandoned
it in the intervening 15 years—four through legislative en-
actments and one through judicial decision. Streib, supra,
at 5, 7; State v. Furman, 122 Wash. 2d 440, 858 P. 2d 1092
(1993) (en banc).
Though less dramatic than the change from Penry to At-
kins (“telling,” to borrow the word Atkins used to describe
this difference, 536 U. S., at 315, n. 18), we still consider the
change from Stanford to this case to be significant. As
noted in Atkins, with respect to the States that had aban-

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doned the death penalty for the mentally retarded since
Penry, “[i]t is not so much the number of these States that
is significant, but the consistency of the direction of change.”
536 U. S., at 315. In particular we found it significant that,
in the wake of Penry, no State that had already prohibited
the execution of the mentally retarded had passed legislation
to reinstate the penalty. 536 U. S., at 315–316. The num-
ber of States that have abandoned capital punishment for
juvenile offenders since Stanford is smaller than the number
of States that abandoned capital punishment for the mentally
retarded after Penry; yet we think the same consistency of
direction of change has been demonstrated. Since Stanford,
no State that previously prohibited capital punishment for
juveniles has reinstated it. This fact, coupled with the
trend toward abolition of the juvenile death penalty, carries
special force in light of the general popularity of anticrime
legislation, Atkins, supra, at 315, and in light of the particu-
lar trend in recent years toward cracking down on juvenile
crime in other respects, see H. Snyder & M. Sickmund, Na-
tional Center for Juvenile Justice, Juvenile Offenders and
Victims: 1999 National Report 89, 133 (Sept. 1999); Scott &
Grisso, The Evolution of Adolescence: A Developmental Per-
spective on Juvenile Justice Reform, 88 J. Crim. L. & C. 137,
148 (1997). Any difference between this case and Atkins
with respect to the pace of abolition is thus counterbalanced
by the consistent direction of the change.
The slower pace of abolition of the juvenile death penalty
over the past 15 years, moreover, may have a simple explana-
tion. When we heard Penry, only two death penalty States
had already prohibited the execution of the mentally re-
tarded. When we heard Stanford, by contrast, 12 death
penalty States had already prohibited the execution of any
juvenile under 18, and 15 had prohibited the execution of any
juvenile under 17. If anything, this shows that the impro-
priety of executing juveniles between 16 and 18 years of age

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gained wide recognition earlier than the impropriety of exe-
cuting the mentally retarded. In the words of the Missouri
Supreme Court: “It would be the ultimate in irony if the
very fact that the inappropriateness of the death penalty for
juveniles was broadly recognized sooner than it was recog-
nized for the mentally retarded were to become a reason to
continue the execution of juveniles now that the execution of
the mentally retarded has been barred.” 112 S. W. 3d, at
408, n. 10.
Petitioner cannot show national consensus in favor of capi-
tal punishment for juveniles but still resists the conclusion
that any consensus exists against it. Petitioner supports
this position with, in particular, the observation that when
the Senate ratified the International Covenant on Civil and
Political Rights (ICCPR), Dec. 19, 1966, 999 U. N. T. S. 171
(entered into force Mar. 23, 1976), it did so subject to the
President’s proposed reservation regarding Article 6(5) of
that treaty, which prohibits capital punishment for juveniles.
Brief for Petitioner 27. This reservation at best provides
only faint support for petitioner’s argument. First, the res-
ervation was passed in 1992; since then, five States have
abandoned capital punishment for juveniles. Second, Con-
gress considered the issue when enacting the Federal Death
Penalty Act in 1994, and determined that the death penalty
should not extend to juveniles. See 18 U. S. C. § 3591. The
reservation to Article 6(5) of the ICCPR provides minimal
evidence that there is not now a national consensus against
juvenile executions.
As in Atkins, the objective indicia of consensus in this
case—the rejection of the juvenile death penalty in the ma-
jority of States; the infrequency of its use even where it re-
mains on the books; and the consistency in the trend toward
abolition of the practice—provide sufficient evidence that
today our society views juveniles, in the words Atkins used
respecting the mentally retarded, as “categorically less cul-
pable than the average criminal.” 536 U. S., at 316.

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B
A majority of States have rejected the imposition of the
death penalty on juvenile offenders under 18, and we now
hold this is required by the Eighth Amendment.
Because the death penalty is the most severe punishment,
the Eighth Amendment applies to it with special force.
Thompson, 487 U. S., at 856 (O’Connor, J., concurring in
judgment). Capital punishment must be limited to those of-
fenders who commit “a narrow category of the most serious
crimes” and whose extreme culpability makes them “the
most deserving of execution.” Atkins, supra, at 319. This
principle is implemented throughout the capital sentencing
process. States must give narrow and precise definition to
the aggravating factors that can result in a capital sentence.
Godfrey v. Georgia, 446 U. S. 420, 428–429 (1980) (plurality
opinion). In any capital case a defendant has wide latitude
to raise as a mitigating factor “any aspect of [his or her]
character or record and any of the circumstances of the of-
fense that the defendant proffers as a basis for a sentence
less than death.” Lockett v. Ohio, 438 U. S. 586, 604 (1978)
(plurality opinion); Eddings v. Oklahoma, 455 U. S. 104, 110–
112 (1982); see also Johnson v. Texas, 509 U. S. 350, 359–362
(1993) (summarizing the Court’s jurisprudence after Fur-
man v. Georgia, 408 U. S. 238 (1972) (per curiam), with re-
spect to a sentencer’s consideration of aggravating and miti-
gating factors). There are a number of crimes that beyond
question are severe in absolute terms, yet the death penalty
may not be imposed for their commission. Coker v. Georgia,
433 U. S. 584 (1977) (rape of an adult woman); Enmund v.
Florida, 458 U. S. 782 (1982) (felony murder where defendant
did not kill, attempt to kill, or intend to kill). The death
penalty may not be imposed on certain classes of offenders,
such as juveniles under 16, the insane, and the mentally re-
tarded, no matter how heinous the crime. Thompson v.
Oklahoma, supra; Ford v. Wainwright, 477 U. S. 399 (1986);
Atkins, supra. These rules vindicate the underlying princi-

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ple that the death penalty is reserved for a narrow category
of crimes and offenders.
Three general differences between juveniles under 18 and
adults demonstrate that juvenile offenders cannot with relia-
bility be classified among the worst offenders. First, as any
parent knows and as the scientific and sociological studies
respondent and his amici cite tend to confirm, “[a] lack of
maturity and an underdeveloped sense of responsibility are
found in youth more often than in adults and are more under-
standable among the young. These qualities often result in
impetuous and ill-considered actions and decisions.” John-
son, supra, at 367; see also Eddings, supra, at 115–116
(“Even the normal 16-year-old customarily lacks the matu-
rity of an adult”). It has been noted that “adolescents are
overrepresented statistically in virtually every category of
reckless behavior.” Arnett, Reckless Behavior in Adoles-
cence: A Developmental Perspective, 12 Developmental Rev.
339 (1992). In recognition of the comparative immaturity
and irresponsibility of juveniles, almost every State prohibits
those under 18 years of age from voting, serving on juries,
or marrying without parental consent. See Appendixes
B–D, infra.
The second area of difference is that juveniles are more
vulnerable or susceptible to negative influences and outside
pressures, including peer pressure. Eddings, supra, at 115
(“[Y]outh is more than a chronological fact. It is a time and
condition of life when a person may be most susceptible to
influence and to psychological damage”). This is explained
in part by the prevailing circumstance that juveniles have
less control, or less experience with control, over their own
environment. See Steinberg & Scott, Less Guilty by Rea-
son of Adolescence: Developmental Immaturity, Diminished
Responsibility, and the Juvenile Death Penalty, 58 Am. Psy-
chologist 1009, 1014 (2003) (hereinafter Steinberg & Scott)
(“[A]s legal minors, [juveniles] lack the freedom that adults
have to extricate themselves from a criminogenic setting”).

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The third broad difference is that the character of a juve-
nile is not as well formed as that of an adult. The personal-
ity traits of juveniles are more transitory, less fixed. See
generally E. Erikson, Identity: Youth and Crisis (1968).
These differences render suspect any conclusion that a ju-
venile falls among the worst offenders. The susceptibility
of juveniles to immature and irresponsible behavior means
“their irresponsible conduct is not as morally reprehensible
as that of an adult.” Thompson, supra, at 835 (plurality
opinion). Their own vulnerability and comparative lack of
control over their immediate surroundings mean juveniles
have a greater claim than adults to be forgiven for failing to
escape negative influences in their whole environment. See
Stanford, 492 U. S., at 395 (Brennan, J., dissenting). The re-
ality that juveniles still struggle to define their identity
means it is less supportable to conclude that even a heinous
crime committed by a juvenile is evidence of irretrievably
depraved character. From a moral standpoint it would be
misguided to equate the failings of a minor with those of an
adult, for a greater possibility exists that a minor’s character
deficiencies will be reformed. Indeed, “[t]he relevance of
youth as a mitigating factor derives from the fact that the
signature qualities of youth are transient; as individuals ma-
ture, the impetuousness and recklessness that may dominate
in younger years can subside.” Johnson, supra, at 368; see
also Steinberg & Scott 1014 (“For most teens, [risky or anti-
social] behaviors are fleeting; they cease with maturity as
individual identity becomes settled. Only a relatively small
proportion of adolescents who experiment in risky or illegal
activities develop entrenched patterns of problem behavior
that persist into adulthood”).
In Thompson, a plurality of the Court recognized the im-
port of these characteristics with respect to juveniles under
16, and relied on them to hold that the Eighth Amendment
prohibited the imposition of the death penalty on juveniles

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below that age. 487 U. S., at 833–838. We conclude the
same reasoning applies to all juvenile offenders under 18.
Once the diminished culpability of juveniles is recognized,
it is evident that the penological justifications for the death
penalty apply to them with lesser force than to adults. We
have held there are two distinct social purposes served by
the death penalty: “ ‘retribution and deterrence of capital
crimes by prospective offenders.’ ” Atkins, 536 U. S., at 319
(quoting Gregg v. Georgia, 428 U. S. 153, 183 (1976) ( joint
opinion of Stewart, Powell, and Stevens, JJ.)). As for ret-
ribution, we remarked in Atkins that “[i]f the culpability of
the average murderer is insufficient to justify the most ex-
treme sanction available to the State, the lesser culpability
of the mentally retarded offender surely does not merit that
form of retribution.” 536 U. S., at 319. The same conclu-
sions follow from the lesser culpability of the juvenile of-
fender. Whether viewed as an attempt to express the com-
munity’s moral outrage or as an attempt to right the balance
for the wrong to the victim, the case for retribution is not as
strong with a minor as with an adult. Retribution is not
proportional if the law’s most severe penalty is imposed on
one whose culpability or blameworthiness is diminished, to a
substantial degree, by reason of youth and immaturity.
As for deterrence, it is unclear whether the death penalty
has a significant or even measurable deterrent effect on juve-
niles, as counsel for petitioner acknowledged at oral argu-
ment. Tr. of Oral Arg. 48. In general we leave to legisla-
tures the assessment of the efficacy of various criminal
penalty schemes, see Harmelin v. Michigan, 501 U. S. 957,
998–999 (1991) (Kennedy, J., concurring in part and concur-
ring in judgment). Here, however, the absence of evidence
of deterrent effect is of special concern because the same
characteristics that render juveniles less culpable than
adults suggest as well that juveniles will be less susceptible
to deterrence. In particular, as the plurality observed in

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Thompson, “[t]he likelihood that the teenage offender has
made the kind of cost-benefit analysis that attaches any
weight to the possibility of execution is so remote as to be
virtually nonexistent.” 487 U. S., at 837. To the extent the
juvenile death penalty might have residual deterrent effect,
it is worth noting that the punishment of life imprisonment
without the possibility of parole is itself a severe sanction, in
particular for a young person.
In concluding that neither retribution nor deterrence pro-
vides adequate justification for imposing the death penalty
on juvenile offenders, we cannot deny or overlook the brutal
crimes too many juvenile offenders have committed. See
Brief for Alabama et al. as Amici Curiae. Certainly it can
be argued, although we by no means concede the point, that
a rare case might arise in which a juvenile offender has suf-
ficient psychological maturity, and at the same time demon-
strates sufficient depravity, to merit a sentence of death.
Indeed, this possibility is the linchpin of one contention
pressed by petitioner and his amici. They assert that even
assuming the truth of the observations we have made about
juveniles’ diminished culpability in general, jurors nonethe-
less should be allowed to consider mitigating arguments re-
lated to youth on a case-by-case basis, and in some cases to
impose the death penalty if justified. A central feature of
death penalty sentencing is a particular assessment of the
circumstances of the crime and the characteristics of the of-
fender. The system is designed to consider both aggravat-
ing and mitigating circumstances, including youth, in every
case. Given this Court’s own insistence on individualized
consideration, petitioner maintains that it is both arbitrary
and unnecessary to adopt a categorical rule barring impo-
sition of the death penalty on any offender under 18 years
of age.
We disagree. The differences between juvenile and adult
offenders are too marked and well understood to risk allow-

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ing a youthful person to receive the death penalty despite
insufficient culpability. An unacceptable likelihood exists
that the brutality or cold-blooded nature of any particular
crime would overpower mitigating arguments based on
youth as a matter of course, even where the juvenile offend-
er’s objective immaturity, vulnerability, and lack of true de-
pravity should require a sentence less severe than death. In
some cases a defendant’s youth may even be counted against
him. In this very case, as we noted above, the prosecutor
argued Simmons’ youth was aggravating rather than miti-
gating. Supra, at 558. While this sort of overreaching
could be corrected by a particular rule to ensure that the
mitigating force of youth is not overlooked, that would not
address our larger concerns.
It is difficult even for expert psychologists to differentiate
between the juvenile offender whose crime reflects unfortu-
nate yet transient immaturity, and the rare juvenile offender
whose crime reflects irreparable corruption. See Stein-
berg & Scott 1014–1016. As we understand it, this difficulty
underlies the rule forbidding psychiatrists from diagnosing
any patient under 18 as having antisocial personality dis-
order, a disorder also referred to as psychopathy or sociopa-
thy, and which is characterized by callousness, cynicism, and
contempt for the feelings, rights, and suffering of others.
American Psychiatric Association, Diagnostic and Statistical
Manual of Mental Disorders 701–706 (4th ed. text rev. 2000);
see also Steinberg & Scott 1015. If trained psychiatrists
with the advantage of clinical testing and observation re-
frain, despite diagnostic expertise, from assessing any juve-
nile under 18 as having antisocial personality disorder, we
conclude that States should refrain from asking jurors to
issue a far graver condemnation—that a juvenile offender
merits the death penalty. When a juvenile offender com-
mits a heinous crime, the State can exact forfeiture of some

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of the most basic liberties, but the State cannot extinguish
his life and his potential to attain a mature understanding of
his own humanity.
Drawing the line at 18 years of age is subject, of course, to
the objections always raised against categorical rules. The
qualities that distinguish juveniles from adults do not disap-
pear when an individual turns 18. By the same token, some
under 18 have already attained a level of maturity some
adults will never reach. For the reasons we have discussed,
however, a line must be drawn. The plurality opinion in
Thompson drew the line at 16. In the intervening years the
Thompson plurality’s conclusion that offenders under 16 may
not be executed has not been challenged. The logic of
Thompson extends to those who are under 18. The age of
18 is the point where society draws the line for many pur-
poses between childhood and adulthood. It is, we conclude,
the age at which the line for death eligibility ought to rest.
These considerations mean Stanford v. Kentucky should
be deemed no longer controlling on this issue. To the extent
Stanford was based on review of the objective indicia of con-
sensus that obtained in 1989, 492 U. S., at 370–371, it suffices
to note that those indicia have changed. Supra, at 564–567.
It should be observed, furthermore, that the Stanford Court
should have considered those States that had abandoned the
death penalty altogether as part of the consensus against the
juvenile death penalty, 492 U. S., at 370, n. 2; a State’s deci-
sion to bar the death penalty altogether of necessity demon-
strates a judgment that the death penalty is inappropriate
for all offenders, including juveniles. Last, to the extent
Stanford was based on a rejection of the idea that this Court
is required to bring its independent judgment to bear on the
proportionality of the death penalty for a particular class of
crimes or offenders, id., at 377–378 (plurality opinion), it suf-
fices to note that this rejection was inconsistent with prior
Eighth Amendment decisions, Thompson, 487 U. S., at 833–

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838 (plurality opinion); Enmund, 458 U. S., at 797; Coker, 433
U. S., at 597 (plurality opinion). It is also inconsistent with
the premises of our recent decision in Atkins. 536 U. S., at
312–313, 317–321.
In holding that the death penalty cannot be imposed upon
juvenile offenders, we take into account the circumstance
that some States have relied on Stanford in seeking the
death penalty against juvenile offenders. This considera-
tion, however, does not outweigh our conclusion that Stan-
ford should no longer control in those few pending cases or
in those yet to arise.
IV
Our determination that the death penalty is disproportion-
ate punishment for offenders under 18 finds confirmation in
the stark reality that the United States is the only country
in the world that continues to give official sanction to the
juvenile death penalty. This reality does not become con-
trolling, for the task of interpreting the Eighth Amendment
remains our responsibility. Yet at least from the time of the
Court’s decision in Trop, the Court has referred to the laws
of other countries and to international authorities as instruc-
tive for its interpretation of the Eighth Amendment’s prohi-
bition of “cruel and unusual punishments.” 356 U. S., at
102–103 (plurality opinion) (“The civilized nations of the
world are in virtual unanimity that statelessness is not to be
imposed as punishment for crime”); see also Atkins, supra,
at 317, n. 21 (recognizing that “within the world community,
the imposition of the death penalty for crimes committed
by mentally retarded offenders is overwhelmingly disap-
proved”); Thompson, supra, at 830–831, and n. 31 (plurality
opinion) (noting the abolition of the juvenile death penalty
“by other nations that share our Anglo-American heritage,
and by the leading members of the Western European com-
munity,” and observing that “[w]e have previously recog-
nized the relevance of the views of the international commu-

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nity in determining whether a punishment is cruel and un-
usual”); Enmund, supra, at 796–797, n. 22 (observing that
“the doctrine of felony murder has been abolished in Eng-
land and India, severely restricted in Canada and a number
of other Commonwealth countries, and is unknown in conti-
nental Europe”); Coker, supra, at 596, n. 10 (plurality opin-
ion) (“It is . . . not irrelevant here that out of 60 major nations
in the world surveyed in 1965, only 3 retained the death pen-
alty for rape where death did not ensue”).
As respondent and a number of amici emphasize, Article
37 of the United Nations Convention on the Rights of the
Child, which every country in the world has ratified save for
the United States and Somalia, contains an express prohibi-
tion on capital punishment for crimes committed by juveniles
under 18. United Nations Convention on the Rights of the
Child, Art. 37, Nov. 20, 1989, 1577 U. N. T. S. 3, 28 I. L. M.
1448, 1468–1470 (entered into force Sept. 2, 1990); Brief for
Respondent 48; Brief for European Union et al. as Amici
Curiae 12–13; Brief for President James Earl Carter, Jr.,
et al. as Amici Curiae 9; Brief for Former U. S. Diplomats
Morton Abramowitz et al. as Amici Curiae 7; Brief for
Human Rights Committee of the Bar of England and Wales
et al. as Amici Curiae 13–14. No ratifying country has en-
tered a reservation to the provision prohibiting the execu-
tion of juvenile offenders. Parallel prohibitions are con-
tained in other significant international covenants. See
ICCPR, Art. 6(5), 999 U. N. T. S., at 175 (prohibiting capital
punishment for anyone under 18 at the time of offense)
(signed and ratified by the United States subject to a reser-
vation regarding Article 6(5), as noted, supra, at 567); Amer-
ican Convention on Human Rights: Pact of San Jose´, Costa
Rica, Art. 4(5), Nov. 22, 1969, 1144 U. N. T. S. 146 (entered
into force July 19, 1978) (same); African Charter on the
Rights and Welfare of the Child, Art. 5(3), OAU Doc. CAB/
LEG/ 24.9/49 (1990) (entered into force Nov. 29, 1999) (same).

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Respondent and his amici have submitted, and petitioner
does not contest, that only seven countries other than the
United States have executed juvenile offenders since 1990:
Iran, Pakistan, Saudi Arabia, Yemen, Nigeria, the Demo-
cratic Republic of Congo, and China. Since then each of
these countries has either abolished capital punishment for
juveniles or made public disavowal of the practice. Brief for
Respondent 49–50. In sum, it is fair to say that the United
States now stands alone in a world that has turned its face
against the juvenile death penalty.
Though the international covenants prohibiting the juve-
nile death penalty are of more recent date, it is instructive
to note that the United Kingdom abolished the juvenile death
penalty before these covenants came into being. The
United Kingdom’s experience bears particular relevance
here in light of the historic ties between our countries and
in light of the Eighth Amendment’s own origins. The
Amendment was modeled on a parallel provision in the Eng-
lish Declaration of Rights of 1689, which provided: “[E]xces-
sive Bail ought not to be required nor excessive Fines im-
posed; nor cruel and unusual Punishments inflicted.” 1 W. &
M., ch. 2, § 10, in 3 Eng. Stat. at Large 441 (1770); see also
Trop, supra, at 100 (plurality opinion). As of now, the
United Kingdom has abolished the death penalty in its en-
tirety; but, decades before it took this step, it recognized the
disproportionate nature of the juvenile death penalty; and it
abolished that penalty as a separate matter. In 1930 an of-
ficial committee recommended that the minimum age for exe-
cution be raised to 21. House of Commons Report from the
Select Committee on Capital Punishment (1930), 193, p. 44.
Parliament then enacted the Children and Young Person’s
Act of 1933, 23 Geo. 5, ch. 12, which prevented execution
of those aged 18 at the date of the sentence. And in 1948,
Parliament enacted the Criminal Justice Act, 11 & 12 Geo. 6,
ch. 58, prohibiting the execution of any person under 18 at
the time of the offense. In the 56 years that have passed

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578 ROPER v. SIMMONS
Opinion of the Court
since the United Kingdom abolished the juvenile death pen-
alty, the weight of authority against it there, and in the inter-
national community, has become well established.
It is proper that we acknowledge the overwhelming
weight of international opinion against the juvenile death
penalty, resting in large part on the understanding that the
instability and emotional imbalance of young people may
often be a factor in the crime. See Brief for Human Rights
Committee of the Bar of England and Wales et al. as Amici
Curiae 10–11. The opinion of the world community, while
not controlling our outcome, does provide respected and sig-
nificant confirmation for our own conclusions.
Over time, from one generation to the next, the Constitu-
tion has come to earn the high respect and even, as Madison
dared to hope, the veneration of the American people. See
The Federalist No. 49, p. 314 (C. Rossiter ed. 1961). The
document sets forth, and rests upon, innovative principles
original to the American experience, such as federalism; a
proven balance in political mechanisms through separation of
powers; specific guarantees for the accused in criminal cases;
and broad provisions to secure individual freedom and pre-
serve human dignity. These doctrines and guarantees are
central to the American experience and remain essential to
our present-day self-definition and national identity. Not
the least of the reasons we honor the Constitution, then, is
because we know it to be our own. It does not lessen our
fidelity to the Constitution or our pride in its origins to ac-
knowledge that the express affirmation of certain fundamen-
tal rights by other nations and peoples simply underscores
the centrality of those same rights within our own heritage
of freedom.
* * *
The Eighth and Fourteenth Amendments forbid imposi-
tion of the death penalty on offenders who were under the
age of 18 when their crimes were committed. The judgment

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579 Cite as: 543 U. S. 551 (2005)
Appendix A to opinion of the Court
of the Missouri Supreme Court setting aside the sentence of
death imposed upon Christopher Simmons is affirmed.
It is so ordered.
APPENDIX A TO OPINION OF THE COURT
I. STATES THAT PERMIT THE IMPOSITION OF THE DEATH
PENALTY ON JUVENILES
Alabama Ala. Code § 13A–6–2(c) (West 2004) (no express mini-
mum age)
Arizona Ariz. Rev. Stat. Ann. § 13–703(A) (West Supp. 2004)
(same)
Arkansas Ark. Code Ann. § 5–4–615 (Michie 1997) (same)
Delaware Del. Code Ann., Tit. 11 (Lexis 1995) (same)
Florida Fla. Stat. § 985.225(1) (2003) (same)
Georgia Ga. Code Ann. § 17–9–3 (Lexis 2004) (same)
Idaho Idaho Code § 18–4004 (Michie 2004) (same)
Kentucky Ky. Rev. Stat. Ann. § 640.040(1) (Lexis 1999) (minimum
age of 16)
Louisiana La. Stat. Ann. § 14:30(C) (West Supp. 2005) (no express
minimum age)
Mississippi Miss. Code Ann. § 97–3–21 (Lexis 2000) (same)
Missouri Mo. Rev. Stat. Ann. § 565.020 (2000) (minimum age of
16)
Nevada Nev. Rev. Stat. § 176.025 (2003) (minimum age of 16)
New Hampshire N. H. Rev. Stat. Ann. § 630:1(V) (West 1996) (minimum
age of 17)
North Carolina N. C. Gen. Stat. § 14–17 (Lexis 2003) (minimum age of
17, except that those under 17 who commit murder
while serving a prison sentence for a previous murder
may receive the death penalty)
Oklahoma Okla. Stat. Ann., Tit. 21, § 701.10 (West 2002) (no ex-
press minimum age)
Pennsylvania 18 Pa. Cons. Stat. § 1102 (2002) (same)
South Carolina S. C. Code Ann. § 16–3–20 (West Supp. 2004 and main
ed.) (same)
Texas Tex. Penal Code Ann. § 8.07(c) (West Supp. 2004–2005)
(minimum age of 17)
Utah Utah Code Ann. § 76–3–206(1) (Lexis 2003) (no express
minimum age)

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580 ROPER v. SIMMONS
Appendix A to opinion of the Court
Virginia Va. Code Ann. § 18.2–10(a) (Lexis 2004) (minimum age
of 16)
II. STATES THAT RETAIN THE DEATH PENALTY, BUT SET
THE MINIMUM AGE AT 18
California Cal. Penal Code Ann. § 190.5 (West 1999)
Colorado Colo. Rev. Stat. § 18–1.4–102(1)(a) (Lexis 2004)
Connecticut Conn. Gen. Stat. § 53a–46a(h) (2005)
Illinois Ill. Comp. Stat., ch. 720, § 5/9–1(b) (West Supp. 2003)
Indiana Ind. Code Ann. § 35–50–2–3 (2004)
Kansas Kan. Stat. Ann. § 21–4622 (1995)
Maryland Md. Crim. Law Code Ann. § 2–202(b)(2)(i) (Lexis 2002)
Montana Mont. Code Ann. § 45–5–102 (2003)
Nebraska Neb. Rev. Stat. § 28–105.01(1) (Supp. 2004)
New Jersey N. J. Stat. Ann. § 2C:11–3(g) (West Supp. 2003)
New Mexico N. M. Stat. Ann. § 31–18–14(A) (2000)
New York N. Y. Penal Law Ann. § 125.27 (West 2004)
Ohio Ohio Rev. Code Ann. § 2929.02(A) (Lexis 2003)
Oregon Ore. Rev. Stat. §§ 161.620, 137.707(2) (2003)
South Dakota S. D. Codified Laws § 23A–27A–42 (West 2004)
Tennessee Tenn. Code Ann. § 37–1–134(a)(1) (1996)
Washington Minimum age of 18 established by judicial decision.
State v. Furman, 122 Wash. 2d 440, 858 P. 2d 1092
(1993)
Wyoming Wyo. Stat. § 6–2–101(b) (Lexis Supp. 2004)
* * *
During the past year, decisions by the highest courts of Kansas and New
York invalidated provisions in those States’ death penalty statutes. State
v. Marsh, 278 Kan. 520, 102 P. 3d 445 (2004) (invalidating provision that
required imposition of the death penalty if aggravating and mitigating
circumstances were found to be in equal balance); People v. LaValle, 3
N. Y. 3d 88, 817 N. E. 2d 341 (2004) (invalidating mandatory requirement
to instruct the jury that, in the case of jury deadlock as to the appropriate
sentence in a capital case, the defendant would receive a sentence of life
imprisonment with parole eligibility after serving a minimum of 20 to 25
years). Due to these decisions, it would appear that in these States the
death penalty remains on the books, but that as a practical matter it might
not be imposed on anyone until there is a change of course in these deci-
sions, or until the respective state legislatures remedy the problems the
courts have identified. Marsh, supra, at 524–526, 544–546, 102 P. 3d, at
452, 464; LaValle, supra, at 99, 817 N. E. 2d, at 344.

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Appendix B to opinion of the Court
III. STATES WITHOUT THE DEATH PENALTY
Alaska
Hawaii
Iowa
Maine
Massachusetts
Michigan
Minnesota
North Dakota
Rhode Island
Vermont
West Virginia
Wisconsin
APPENDIX B TO OPINION OF THE COURT
STATE STATUTES ESTABLISHING A MINIMUM AGE TO VOTE
STATE AGE STATUTE
Alabama 18 Ala. Const., Amdt. No. 579
Alaska 18 Alaska Const., Art. V, § 1; Alaska Stat. § 15–
05.010 (Lexis 2004)
Arizona 18 Ariz. Const., Art. VII, § 2; Ariz. Rev. Stat. § 16–
101 (West 2001)
Arkansas 18 Ark. Code Ann. § 9–25–101 (Lexis 2002)
California 18 Cal. Const., Art. 2, § 2
Colorado 18 Colo. Rev. Stat. § 1–2–101 (Lexis 2004)
Connecticut 18 Conn. Const., Art. 6, § 1; Conn. Gen. Stat. § 9–12
(2005)
Delaware 18 Del. Code Ann., Tit. 15, § 1701 (Michie Supp.
2004)
District of 18 D. C. Code § 1–1001.02(2)(B) (West Supp. 2004)
Columbia
Florida 18 Fla. Stat. ch. 97.041 (2003)
Georgia 18 Ga. Const., Art. 2, § 1, ¶ 2; Ga. Code Ann. § 21–
2–216 (Lexis 2003)
Hawaii Haw. Const., Art. II, § 1; Haw. Rev. Stat. § 11–12
(1995)
Idaho 18 Idaho Code § 34–402 (Michie 2001)
Illinois 18 Ill. Const., Art. III, § 1; Ill. Comp. Stat., ch. 10,
§ 5/3–1 (West 2002)
Indiana 18 Ind. Code Ann. § 3–7–13–1 (2004)
Iowa 18 Iowa Code § 48A.5 (2003)

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582 ROPER v. SIMMONS
Appendix B to opinion of the Court
Kansas 18 Kan. Const., Art. 5, § 1
Kentucky 18 Ky. Const. § 145
Louisiana 18 La. Const., Art. I, § 10; La. Rev. Stat. Ann.
§ 18:101 (West 2004)
Maine 18 Me. Const., Art. II, § 1 (West Supp. 2004); Me.
Rev. Stat. Ann., Tit. 21–A, §§ 111, 111–A (West
1993 and Supp. 2004)
Maryland 18 Md. Elec. Law Code Ann. § 3–102 (Lexis 2002)
Massachusetts 18 Mass. Gen. Laws Ann., ch. 51, § 1 (West Supp.
2005)
Michigan 18 Mich. Comp. Laws Ann. § 168.492 (West 1989)
Minnesota 18 Minn. Stat. § 201.014(1)(a) (2004)
Mississippi 18 Miss. Const., Art. 12, § 241
Missouri 18 Mo. Const., Art. VIII, § 2
Montana 18 Mont. Const., Art. IV, § 2; Mont. Code Ann.
§ 13–1–111 (2003)
Nebraska 18 Neb. Const., Art. VI, § 1; Neb. Rev. Stat. § 32–
110 (2004)
Nevada 18 Nev. Rev. Stat. § 293.485 (2003)
New 18 N. H. Const., Pt. 1, Art. 11
Hampshire
New Jersey 18 N. J. Const., Art. II, § 1, ¶ 3
New Mexico 18 [no provision other than U. S. Const., Amdt.
XXVI]
New York 18 N. Y. Elec. Law Ann. § 5–102 (West 1998)
North 18 N. C. Gen. Stat. Ann. § 163–55 (Lexis 2003)
Carolina
North Dakota 18 N. D. Const., Art. II, § 1
Ohio 18 Ohio Const., Art. V, § 1; Ohio Rev. Code Ann.
§ 3503.01 (Anderson 1996)
Oklahoma 18 Okla. Const., Art. III, § 1
Oregon 18 Ore. Const., Art. II, § 2
Pennsylvania 18 25 Pa. Cons. Stat. Ann. § 2811 (1994)
Rhode Island 18 R. I. Gen. Laws § 17–1–3 (Lexis 2003)
South 18 S. C. Code Ann. § 7–5–610 (West Supp. 2004)
Carolina
South Dakota 18 S. D. Const., Art. VII, § 2; S. D. Codified Laws
Ann. § 12–3–1 (West 2004)
Tennessee 18 Tenn. Code Ann. § 2–2–102 (2003)
Texas 18 Tex. Elec. Code Ann. § 11.002 (West 2003)
Utah 18 Utah Const., Art. IV, § 2; Utah Code Ann.
§ 20A–2–101 (Lexis 2003)
Vermont 18 Vt. Stat. Ann., Tit. 17, § 2121 (Lexis 2002)

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Appendix C to opinion of the Court
Virginia 18 Va. Const., Art. II, § 1
Washington 18 Wash. Const., Art. VI, § 1
West Virginia 18 W. Va. Code § 3–1–3 (Lexis 2002)
Wisconsin 18 Wis. Const., Art. III, § 1; Wis. Stat. § 6.02 (West
2004)
Wyoming 18 Wyo. Stat. Ann. §§ 22–1–102, 22–3–102 (Lexis
Supp. 2004)
* * *
The Twenty-Sixth Amendment to the Constitution of the United States
provides that “[t]he right of citizens of the United States, who are eighteen
years of age or older, to vote shall not be denied or abridged by the United
States or by any State on account of age.”
APPENDIX C TO OPINION OF THE COURT
STATE STATUTES ESTABLISHING A MINIMUM AGE FOR
JURY SERVICE
STATE AGE STATUTE
Alabama 19 Ala. Code § 12–16–60(a)(1) (West 1995)
Alaska 18 Alaska Stat. § 09.20.010(a)(3) (Lexis 2004)
Arizona 18 Ariz. Rev. Stat. § 21–301(D) (West 2002)
Arkansas 18 Ark. Code Ann. §§ 16–31–101, 16–32–302 (Lexis
Supp. 2003)
California 18 Cal. Civ. Proc. § 203(a)(2) (West Supp. 2005)
Colorado 18 Colo. Rev. Stat. § 13–71–105(2)(a) (Lexis 2004)
Connecticut 18 Conn. Gen. Stat. § 51–217(a) (2005)
Delaware 18 Del. Code Ann., Tit. 10, § 4509(b)(2) (Michie
1999)
District of 18 D. C. Code § 11–1906(b)(1)(C) (West 2001)
Columbia
Florida 18 Fla. Stat. § 40.01 (2003)
Georgia 18 Ga. Code Ann. §§ 15–12–60, 15–12–163 (Lexis
2001)
Hawaii 18 Haw. Rev. Stat. § 612–4(a)(1) (Supp. 2004)
Idaho 18 Idaho Code § 2–209(2)(a) (Michie 2004)
Illinois 18 Ill. Comp. Stat., ch. 705, § 305/2 (West 2002)
Indiana 18 Ind. Code § 33–28–4–8 (2004)
Iowa 18 Iowa Code § 607A.4(1)(a) (2003)
Kansas 18 Kan. Stat. Ann. § 43–156 (2000) ( jurors must be
qualified to be electors); Kan. Const., Art. 5, § 1
(person must be 18 to be qualified elector)

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584 ROPER v. SIMMONS
Appendix C to opinion of the Court
Kentucky 18 Ky. Rev. Stat. Ann. § 29A.080(2)(a) (Lexis Supp.
2004)
Louisiana 18 La. Code Crim. Proc. Ann., Art. 401(A)(2)
(West 2003)
Maine 18 Me. Rev. Stat. Ann., Tit. 14, § 1211 (West 1980)
Maryland 18 Md. Cts. & Jud. Proc. Code Ann. § 8–104 (Lexis
2002)
Massachusetts 18 Mass. Gen. Laws Ann., ch. 234, § 1 (West 2000)
( jurors must be qualified to vote); ch. 51, § 1
(West Supp. 2005) (person must be 18 to vote)
Michigan 18 Mich. Comp. Laws Ann. § 600.1307a(1)(a) (West
Supp. 2004)
Minnesota 18 Minn. Dist. Ct. Rule 808(b)(2) (2004)
Mississippi 21 Miss. Code Ann. § 13–5–1 (Lexis 2002)
Missouri 21 Mo. Rev. Stat. § 494.425(1) (2000)
Montana 18 Mont. Code Ann. § 3–15–301 (2003)
Nebraska 19 Neb. Rev. Stat. § 25–1601 (Supp. 2004)
Nevada 18 Nev. Rev. Stat. § 6.010 (2003) ( juror must be
qualified elector); § 293.485 (person must be 18
to vote)
New 18 N. H. Rev. Stat. Ann. § 500–A:7–a(I) (Lexis
Hampshire Supp. 2004)
New Jersey 18 N. J. Stat. Ann. § 2B:20 –1(a) (West 2004
Pamphlet)
New Mexico 18 N. M. Stat. Ann. § 38–5–1 (1998)
New York 18 N. Y. Jud. Law Ann. § 510(2) (West 2003)
North 18 N. C. Gen. Stat. Ann. § 9–3 (Lexis 2003)
Carolina
North Dakota 18 N. D. Cent. Code § 27– 09.1– 08(2)(b) (Lexis
Supp. 2003)
Ohio 18 Ohio Rev. Code Ann. § 2313.42 (Anderson 2001)
Oklahoma 18 Okla. Stat. Ann., Tit. 38, § 28 (West Supp. 2005)
Rhode Island 18 R. I. Gen. Laws § 9–9–1.1(a)(2) (Lexis Supp.
2005)
South 18 S. C. Code Ann. § 14–7–130 (West Supp. 2004)
Carolina
South Dakota 18 S. D. Codified Laws § 16–13–10 (2004)
Tennessee 18 Tenn. Code Ann. § 22–1–101 (1994)
Texas 18 Tex. Govt. Code Ann. § 62.102(1) (West 1998)
Utah 18 Utah Code Ann. § 78–46–7(1)(b) (Lexis 2002)
Vermont 18 Vt. Stat. Ann., Tit. 4, § 962(a)(1) (Lexis 1999)
( jurors must have attained age of majority);
Tit. 1, § 173 (Lexis 2003) (age of majority is 18)

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585 Cite as: 543 U. S. 551 (2005)
Appendix D to opinion of the Court
Virginia 18 Va. Code Ann. § 8.01–337 (Lexis 2000)
Washington 18 Wash. Rev. Code Ann. § 2.36.070 (West 2004)
West Virginia 18 W. Va. Code § 52–1–8(b)(1) (Lexis 2000)
Wisconsin 18 Wis. Stat. § 756.02 (West 2001)
Wyoming 18 Wyo. Stat. Ann. § 1–11–101 (Lexis 2003) ( jurors
must be adults); § 14–1–101 (person becomes an
adult at 18)
APPENDIX D TO OPINION OF THE COURT
STATE STATUTES ESTABLISHING A MINIMUM AGE FOR MAR-
RIAGE WITHOUT PARENTAL OR JUDICIAL CONSENT
STATE AGE STATUTE
Alabama 18 Ala. Code § 30–1–5 (West Supp. 2004)
Alaska 18 Alaska Stat. §§ 25.05.011, 25.05.171 (Lexis 2004)
Arizona 18 Ariz. Rev. Stat. Ann. § 25–102 (West Supp.
2004)
Arkansas 18 Ark. Code Ann. §§ 9–11–102, 9–11–208 (Lexis
2002)
California 18 Cal. Fam. Code Ann. § 301 (West 2004)
Colorado 18 Colo. Rev. Stat. Ann. § 14–2–106 (Lexis 2004)
Connecticut 18 Conn. Gen. Stat. § 46b–30 (2005)
Delaware 18 Del. Code Ann., Tit. 13, § 123 (Lexis 1999)
District of 18 D. C. Code § 46–411 (West 2001)
Columbia
Florida 18 Fla. Stat. §§ 741.04, 741.0405 (2003)
Georgia 16 Ga. Code Ann. §§ 19–3–2, 19–3–37 (Lexis 2004)
(those under 18 must obtain parental consent
unless female applicant is pregnant or both ap-
plicants are parents of a living child, in which
case minimum age to marry without consent is
16)
Hawaii 18 Haw. Rev. Stat. § 572–2 (1993)
Idaho 18 Idaho Code § 32–202 (Michie 1996)
Illinois 18 Ill. Comp. Stat., ch. 750, § 5/203 (West 2002)
Indiana 18 Ind. Code Ann. §§ 31–11–1–4, 31–11–1–5, 31–11–
2–1, 31–11–2–3 (2004)
Iowa 18 Iowa Code § 595.2 (2003)
Kansas 18 Kan. Stat. Ann. § 23–106 (Supp. 2003)
Kentucky 18 Ky. Rev. Stat. Ann. §§ 402.020, 402.210 (Lexis
1999)
Louisiana 18 La. Children’s Code Ann., Arts. 1545, 1547
(West 2004) (minors may not marry without

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586 ROPER v. SIMMONS
Appendix D to opinion of the Court
consent); La. Civ. Code Ann., Art. 29 (West
1999) (age of majority is 18)
Maine 18 Me. Rev. Stat. Ann., Tit. 19–A, § 652 (West 1998
and Supp. 2004)
Maryland 16 Md. Fam. Law Code Ann. § 2–301 (Lexis 2004)
(those under 18 must obtain parental consent
unless female applicant can present proof of
pregnancy or a child, in which case minimum
age to marry without consent is 16)
Massachusetts 18 Mass. Gen. Laws Ann., ch. 207, §§ 7, 24, 25
(West 1998)
Michigan 18 Mich. Comp. Laws Ann. § 551.103 (West 2005)
Minnesota 18 Minn. Stat. § 517.02 (2004)
Mississippi 15/17 Miss. Code Ann. § 93–1–5 (Lexis 2004) (female
applicants must be 15; male applicants must be
17)
Missouri 18 Mo. Rev. Stat. § 451.090 (2000)
Montana 18 Mont. Code Ann. §§ 40–1–202, 40–1–213 (2003)
Nebraska 19 Neb. Rev. Stat. § 42–105 (2004) (minors must
have parental consent to marry); § 43–2101 (de-
fining “minor” as a person under 19)
Nevada 18 Nev. Rev. Stat. § 122.020 (2003)
New 18 N. H. Rev. Stat. Ann. § 457:5 (West 1992)
Hampshire
New Jersey 18 N. J. Stat. Ann. § 37:1–6 (West 2002)
New Mexico 18 N. M. Stat. Ann. § 40–1–6 (1999)
New York 18 N. Y. Dom. Rel. Law Ann. § 15 (West Supp.
2005)
North 18 N. C. Gen. Stat. Ann. § 51–2 (Lexis 2003)
Carolina
North Dakota 18 N. D. Cent. Code § 14–03–02 (Lexis 2004)
Ohio 18 Ohio Rev. Code Ann. § 3101.01 (2003)
Oklahoma 18 Okla. Stat. Ann., Tit. 43, § 3 (West Supp. 2005)
Oregon 18 Ore. Rev. Stat. § 106.060 (2003)
Pennsylvania 18 23 Pa. Cons. Stat. § 1304 (1997)
Rhode Island 18 R. I. Gen. Laws § 15–2–11 (Supp. 2004)
South 18 S. C. Code Ann. § 20–1–250 (West Supp. 2004)
Carolina
South Dakota 18 S. D. Codified Laws § 25–1–9 (West 2004)
Tennessee 18 Tenn. Code Ann. § 36–3–106 (1996)
Texas 18 Tex. Fam. Code Ann. §§ 2.101–2.103 (West 1998)
Utah 18 Utah Code Ann. § 30–1–9 (Lexis Supp. 2004)
Vermont 18 Vt. Stat. Ann., Tit. 18, § 5142 (Lexis 2000)

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587 Cite as: 543 U. S. 551 (2005)
O’Connor, J., dissenting
Virginia 18 Va. Code Ann. §§ 20–45.1, 20–48, 20–49 (Lexis
2004)
Washington 18 Wash. Rev. Code Ann. § 26.04.210 (West 2005)
West Virginia 18 W. Va. Code § 48–2–301 (Lexis 2004)
Wisconsin 18 Wis. Stat. § 765.02 (2001)
Wyoming 18 Wyo. Stat. Ann. § 20–1–102 (Lexis 2003)
Justice Stevens, with whom Justice Ginsburg joins,
concurring.
Perhaps even more important than our specific holding
today is our reaffirmation of the basic principle that informs
the Court’s interpretation of the Eighth Amendment. If the
meaning of that Amendment had been frozen when it was
originally drafted, it would impose no impediment to the
execution of 7-year-old children today. See Stanford v.
Kentucky, 492 U. S. 361, 368 (1989) (describing the common
law at the time of the Amendment’s adoption). The evolv-
ing standards of decency that have driven our construction
of this critically important part of the Bill of Rights foreclose
any such reading of the Amendment. In the best tradition
of the common law, the pace of that evolution is a matter for
continuing debate; but that our understanding of the Con-
stitution does change from time to time has been settled
since John Marshall breathed life into its text. If great law-
yers of his day—Alexander Hamilton, for example—were sit-
ting with us today, I would expect them to join Justice
Kennedy’s opinion for the Court. In all events, I do so
without hesitation.
Justice O’Connor, dissenting.
The Court’s decision today establishes a categorical rule
forbidding the execution of any offender for any crime com-
mitted before his 18th birthday, no matter how deliberate,
wanton, or cruel the offense. Neither the objective evidence
of contemporary societal values, nor the Court’s moral pro-
portionality analysis, nor the two in tandem suffice to justify
this ruling.

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588 ROPER v. SIMMONS
O’Connor, J., dissenting
Although the Court finds support for its decision in the
fact that a majority of the States now disallow capital pun-
ishment of 17-year-old offenders, it refrains from asserting
that its holding is compelled by a genuine national consensus.
Indeed, the evidence before us fails to demonstrate conclu-
sively that any such consensus has emerged in the brief
period since we upheld the constitutionality of this practice
in Stanford v. Kentucky, 492 U. S. 361 (1989).
Instead, the rule decreed by the Court rests, ultimately,
on its independent moral judgment that death is a dispropor-
tionately severe punishment for any 17-year-old offender.
I do not subscribe to this judgment. Adolescents as a class
are undoubtedly less mature, and therefore less culpable for
their misconduct, than adults. But the Court has adduced
no evidence impeaching the seemingly reasonable conclusion
reached by many state legislatures: that at least some 17-
year-old murderers are sufficiently mature to deserve the
death penalty in an appropriate case. Nor has it been
shown that capital sentencing juries are incapable of accu-
rately assessing a youthful defendant’s maturity or of giving
due weight to the mitigating characteristics associated with
youth.
On this record—and especially in light of the fact that so
little has changed since our recent decision in Stanford—I
would not substitute our judgment about the moral propriety
of capital punishment for 17-year-old murderers for the judg-
ments of the Nation’s legislatures. Rather, I would demand
a clearer showing that our society truly has set its face
against this practice before reading the Eighth Amendment
categorically to forbid it.
I
A
Let me begin by making clear that I agree with much of
the Court’s description of the general principles that guide
our Eighth Amendment jurisprudence. The Amendment

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589 Cite as: 543 U. S. 551 (2005)
O’Connor, J., dissenting
bars not only punishments that are inherently “ ‘barbaric,’ ”
but also those that are “ ‘excessive’ in relation to the crime
committed.” Coker v. Georgia, 433 U. S. 584, 592 (1977)
(plurality opinion). A sanction is therefore beyond the
State’s authority to inflict if it makes “no measurable contri-
bution” to acceptable penal goals or is “grossly out of propor-
tion to the severity of the crime.” Ibid. The basic “precept
of justice that punishment for crime should be . . . propor-
tioned to [the] offense,” Weems v. United States, 217 U. S.
349, 367 (1910), applies with special force to the death pen-
alty. In capital cases, the Constitution demands that the
punishment be tailored both to the nature of the crime itself
and to the defendant’s “personal responsibility and moral
guilt.” Enmund v. Florida, 458 U. S. 782, 801 (1982); see
also id., at 825 (O’Connor, J., dissenting); Tison v. Arizona,
481 U. S. 137, 149 (1987); Eddings v. Oklahoma, 455 U. S. 104,
111–112 (1982).
It is by now beyond serious dispute that the Eighth
Amendment’s prohibition of “cruel and unusual punish-
ments” is not a static command. Its mandate would be little
more than a dead letter today if it barred only those sanc-
tions—like the execution of children under the age of
seven—that civilized society had already repudiated in 1791.
See ante, at 587 (Stevens, J., concurring); cf. Stanford,
supra, at 368 (discussing the common law rule at the time
the Bill of Rights was adopted). Rather, because “[t]he
basic concept underlying the Eighth Amendment is nothing
less than the dignity of man,” the Amendment “must draw
its meaning from the evolving standards of decency that
mark the progress of a maturing society.” Trop v. Dulles,
356 U. S. 86, 100–101 (1958) (plurality opinion). In discern-
ing those standards, we look to “objective factors to the max-
imum possible extent.” Coker, supra, at 592 (plurality opin-
ion). Laws enacted by the Nation’s legislatures provide the
“clearest and most reliable objective evidence of contempo-
rary values.” Penry v. Lynaugh, 492 U. S. 302, 331 (1989).

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590 ROPER v. SIMMONS
O’Connor, J., dissenting
And data reflecting the actions of sentencing juries, where
available, can also afford “ ‘a significant and reliable objective
index’ ” of societal mores. Coker, supra, at 596 (plurality
opinion) (quoting Gregg v. Georgia, 428 U. S. 153, 181 (1976)
( joint opinion of Stewart, Powell, and Stevens, JJ.)).
Although objective evidence of this nature is entitled to
great weight, it does not end our inquiry. Rather, as the
Court today reaffirms, see ante, at 563, 574–575, “the Consti-
tution contemplates that in the end our own judgment will
be brought to bear on the question of the acceptability of the
death penalty under the Eighth Amendment,” Coker, supra,
at 597 (plurality opinion). “[P]roportionality—at least as re-
gards capital punishment—not only requires an inquiry into
contemporary standards as expressed by legislators and ju-
rors, but also involves the notion that the magnitude of the
punishment imposed must be related to the degree of the
harm inflicted on the victim, as well as to the degree of
the defendant’s blameworthiness.” Enmund, supra, at 815
(O’Connor, J., dissenting). We therefore have a “constitu-
tional obligation” to judge for ourselves whether the death
penalty is excessive punishment for a particular offense or
class of offenders. See Stanford, 492 U. S., at 382 (O’Con-
nor, J., concurring in part and concurring in judgment); see
also Enmund, supra, at 797 (“[I]t is for us ultimately to
judge whether the Eighth Amendment permits imposition of
the death penalty”).
B
Twice in the last two decades, the Court has applied these
principles in deciding whether the Eighth Amendment per-
mits capital punishment of adolescent offenders. In Thomp-
son v. Oklahoma, 487 U. S. 815 (1988), a plurality of four
Justices concluded that the Eighth Amendment barred capi-
tal punishment of an offender for a crime committed before
the age of 16. I concurred in that judgment on narrower
grounds. At the time, 32 state legislatures had “definitely
concluded that no 15-year-old should be exposed to the threat

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of execution,” and no legislature had affirmatively endorsed
such a practice. Id., at 849 (O’Connor, J., concurring in
judgment). While acknowledging that a national consensus
forbidding the execution of 15-year-old offenders “very
likely” did exist, I declined to adopt that conclusion as a mat-
ter of constitutional law without clearer evidentiary support.
Ibid. Nor, in my view, could the issue be decided based on
moral proportionality arguments of the type advanced by
the Court today. Granting the premise “that adolescents
are generally less blameworthy than adults who commit sim-
ilar crimes,” I wrote, “it does not necessarily follow that all
15-year-olds are incapable of the moral culpability that would
justify the imposition of capital punishment.” Id., at 853.
Similarly, we had before us no evidence “that 15-year-olds as
a class are inherently incapable of being deterred from major
crimes by the prospect of the death penalty.” Ibid. I de-
termined instead that, in light of the strong but inconclusive
evidence of a national consensus against capital punishment
of under-16 offenders, concerns rooted in the Eighth Amend-
ment required that we apply a clear statement rule. Be-
cause the capital punishment statute in Thompson did not
specify the minimum age at which commission of a capital
crime would be punishable by death, I concluded that the
statute could not be read to authorize the death penalty for
a 15-year-old offender. Id., at 857–858.
The next year, in Stanford v. Kentucky, supra, the Court
held that the execution of 16- or 17-year-old capital murder-
ers did not violate the Eighth Amendment. I again wrote
separately, concurring in part and concurring in the judg-
ment. At that time, 25 States did not permit the execution
of under-18 offenders, including 13 that lacked the death pen-
alty altogether. See id., at 370. While noting that “[t]he
day may come when there is such general legislative rejec-
tion of the execution of 16- or 17-year-old capital murderers
that a clear national consensus can be said to have devel-
oped,” I concluded that that day had not yet arrived. Id.,

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at 381–382. I reaffirmed my view that, beyond assessing
the actions of legislatures and juries, the Court has a con-
stitutional obligation to judge for itself whether capital
punishment is a proportionate response to the defendant’s
blameworthiness. Id., at 382. Nevertheless, I concluded
that proportionality arguments similar to those endorsed by
the Court today did not justify a categorical Eighth Amend-
ment rule against capital punishment of 16- and 17-year-old
offenders. See ibid. (citing Thompson, supra, at 853–854
(O’Connor, J., concurring in judgment)).
The Court has also twice addressed the constitutionality
of capital punishment of mentally retarded offenders. In
Penry v. Lynaugh, 492 U. S. 302 (1989), decided the same
year as Stanford, we rejected the claim that the Eighth
Amendment barred the execution of the mentally retarded.
At that time, only two States specifically prohibited the prac-
tice, while 14 others did not have capital punishment at all.
492 U. S., at 334. Much had changed when we revisited the
question three Terms ago in Atkins v. Virginia, 536 U. S.
304 (2002). In Atkins, the Court reversed Penry and held
that the Eighth Amendment forbids capital punishment of
mentally retarded offenders. 536 U. S., at 321. In the 13
years between Penry and Atkins, there had been a wave of
legislation prohibiting the execution of such offenders. By
the time we heard Atkins, 30 States barred the death pen-
alty for the mentally retarded, and even among those States
theoretically permitting such punishment, very few had exe-
cuted a mentally retarded offender in recent history. 536
U. S., at 314–316. On the basis of this evidence, the Court
determined that it was “fair to say that a national consensus
ha[d] developed against” the practice. Id., at 316.
But our decision in Atkins did not rest solely on this ten-
tative conclusion. Rather, the Court’s independent moral
judgment was dispositive. The Court observed that men-
tally retarded persons suffer from major cognitive and be-

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havioral deficits, i. e., “subaverage intellectual functioning”
and “significant limitations in adaptive skills such as commu-
nication, self-care, and self-direction that became manifest
before age 18.” Id., at 318. “Because of their impairments,
[such persons] by definition . . . have diminished capacities
to understand and process information, to communicate, to
abstract from mistakes and learn from experience, to engage
in logical reasoning, to control impulses, and to understand
the reactions of others.” Ibid. We concluded that these
deficits called into serious doubt whether the execution of
mentally retarded offenders would measurably contribute to
the principal penological goals that capital punishment is in-
tended to serve—retribution and deterrence. Id., at 319–
321. Mentally retarded offenders’ impairments so diminish
their personal moral culpability that it is highly unlikely that
such offenders could ever deserve the ultimate punishment,
even in cases of capital murder. Id., at 319. And these
same impairments made it very improbable that the threat
of the death penalty would deter mentally retarded persons
from committing capital crimes. Id., at 319–320. Having
concluded that capital punishment of the mentally retarded
is inconsistent with the Eighth Amendment, the Court
“ ‘le[ft] to the State[s] the task of developing appropriate
ways to enforce the constitutional restriction upon [their] ex-
ecution of sentences.’ ” Id., at 317 (quoting Ford v. Wain-
wright, 477 U. S. 399, 416–417 (1986)).
II
A
Although the general principles that guide our Eighth
Amendment jurisprudence afford some common ground, I
part ways with the Court in applying them to the case be-
fore us. As a preliminary matter, I take issue with the
Court’s failure to reprove, or even to acknowledge, the Su-
preme Court of Missouri’s unabashed refusal to follow our

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594 ROPER v. SIMMONS
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controlling decision in Stanford. The lower court concluded
that, despite Stanford’s clear holding and historical recency,
our decision was no longer binding authority because it was
premised on what the court deemed an obsolete assessment
of contemporary values. Quite apart from the merits of the
constitutional question, this was clear error.
Because the Eighth Amendment “draw[s] its meaning
from . . . evolving standards of decency,” Trop, 356 U. S., at
101 (plurality opinion), significant changes in societal mores
over time may require us to reevaluate a prior decision.
Nevertheless, it remains “this Court’s prerogative alone to
overrule one of its precedents.” State Oil Co. v. Khan, 522
U. S. 3, 20 (1997) (emphasis added). That is so even where
subsequent decisions or factual developments may appear to
have “significantly undermined” the rationale for our earlier
holding. United States v. Hatter, 532 U. S. 557, 567 (2001);
see also State Oil Co., supra, at 20; Rodriguez de Quijas v.
Shearson/American Express, Inc., 490 U. S. 477, 484 (1989).
The Eighth Amendment provides no exception to this rule.
On the contrary, clear, predictable, and uniform constitu-
tional standards are especially desirable in this sphere. By
affirming the lower court’s judgment without so much as a
slap on the hand, today’s decision threatens to invite frequent
and disruptive reassessments of our Eighth Amendment
precedents.
B
In determining whether the juvenile death penalty com-
ports with contemporary standards of decency, our in-
quiry begins with the “clearest and most reliable objec-
tive evidence of contemporary values”—the actions of
the Nation’s legislatures. Penry, supra, at 331. As the
Court emphasizes, the overall number of jurisdictions
that currently disallow the execution of under-18 offend-
ers is the same as the number that forbade the execution
of mentally retarded offenders when Atkins was decided.

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Ante, at 564. At present, 12 States and the District of
Columbia do not have the death penalty, while an additional
18 States and the Federal Government authorize capital pun-
ishment but prohibit the execution of under-18 offenders.
See ante, at 580–581 (Appendix A). And here, as in At-
kins, only a very small fraction of the States that permit
capital punishment of offenders within the relevant class
has actually carried out such an execution in recent his-
tory: Six States have executed under-18 offenders in the 16
years since Stanford, while five States had executed men-
tally retarded offenders in the 13 years prior to Atkins. See
Atkins, 536 U. S., at 316; V. Streib, The Juvenile Death
Penalty Today: Death Sentences and Executions for Juve-
nile Crimes, January 1, 1973–December 31, 2004, No. 76,
pp. 15–23 (2005), available at http://www.law.onu.edu/faculty/
streib/documents/JuvDeathDec2004.pdf (last updated Jan.
31, 2005) (as visited Feb. 25, 2005, and available in Clerk of
Court’s case file) (hereinafter Streib). In these respects, the
objective evidence in this case is, indeed, “similar, and in
some respects parallel to,” the evidence upon which we re-
lied in Atkins. Ante, at 564.
While the similarities between the two cases are undeni-
able, the objective evidence of national consensus is margin-
ally weaker here. Most importantly, in Atkins there was
significant evidence of opposition to the execution of the
mentally retarded, but there was virtually no countervailing
evidence of affirmative legislative support for this practice.
Cf. Thompson, 487 U. S., at 849 (O’Connor, J., concurring
in judgment) (attributing significance to the fact that “no
legislature in this country has affirmatively and unequivo-
cally endorsed” capital punishment of 15-year-old offenders).
The States that permitted such executions did so only be-
cause they had not enacted any prohibitory legislation.
Here, by contrast, at least seven States have current statutes
that specifically set 16 or 17 as the minimum age at which

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commission of a capital crime can expose the offender to the
death penalty. See ante, at 579–580 (Appendix A).* Five
of these seven States presently have one or more juvenile
offenders on death row (six if respondent is included in the
count), see Streib 24–31, and four of them have executed at
least one under-18 offender in the past 15 years, see id., at
15–23. In all, there are currently over 70 juvenile offenders
on death row in 12 different States (13 including respondent).
See id., at 11, 24–31. This evidence suggests some measure
of continuing public support for the availability of the death
penalty for 17-year-old capital murderers.
Moreover, the Court in Atkins made clear that it was “not
so much the number of [States forbidding execution of the
mentally retarded] that [was] significant, but the consistency
of the direction of change.” 536 U. S., at 315. In contrast
to the trend in Atkins, the States have not moved uniformly
toward abolishing the juvenile death penalty. Instead, since
our decision in Stanford, two States have expressly reaf-
firmed their support for this practice by enacting statutes
setting 16 as the minimum age for capital punishment. See
Mo. Rev. Stat. § 565.020.2 (2000); Va. Code Ann. § 18.2–10(a)
(Lexis 2004). Furthermore, as the Court emphasized in At-
kins itself, 536 U. S., at 315, n. 18, the pace of legislative
action in this context has been considerably slower than it
was with regard to capital punishment of the mentally re-
*In 12 other States that have capital punishment, under-18 offenders
can be subject to the death penalty as a result of transfer statutes that
permit such offenders to be tried as adults for certain serious crimes.
See ante, at 579–580 (Appendix A). As I observed in Thompson v. Okla-
homa, 487 U. S. 815, 850–852 (1988) (opinion concurring in judgment):
“There are many reasons, having nothing whatsoever to do with capital
punishment, that might motivate a legislature to provide as a general mat-
ter for some [minors] to be channeled into the adult criminal justice proc-
ess.” Accordingly, while these 12 States clearly cannot be counted as op-
posing capital punishment of under-18 offenders, the fact that they permit
such punishment through this indirect mechanism does not necessarily
show affirmative and unequivocal legislative support for the practice.
See ibid.

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tarded. In the 13 years between our decisions in Penry and
Atkins, no fewer than 16 States banned the execution of
mentally retarded offenders. See Atkins, supra, at 314–
315. By comparison, since our decision 16 years ago in Stan-
ford, only four States that previously permitted the execu-
tion of under-18 offenders, plus the Federal Government,
have legislatively reversed course, and one additional State’s
high court has construed the State’s death penalty statute
not to apply to under-18 offenders, see State v. Furman, 122
Wash. 2d 440, 458, 858 P. 2d 1092, 1103 (1993) (en banc). The
slower pace of change is no doubt partially attributable, as
the Court says, to the fact that 12 States had already im-
posed a minimum age of 18 when Stanford was decided.
See ante, at 566–567. Nevertheless, the extraordinary wave
of legislative action leading up to our decision in Atkins pro-
vided strong evidence that the country truly had set itself
against capital punishment of the mentally retarded. Here,
by contrast, the halting pace of change gives reason for
pause.
To the extent that the objective evidence supporting to-
day’s decision is similar to that in Atkins, this merely high-
lights the fact that such evidence is not dispositive in either
of the two cases. After all, as the Court today confirms,
ante, at 563, 574–575, the Constitution requires that “ ‘in the
end our own judgment . . . be brought to bear’ ” in deciding
whether the Eighth Amendment forbids a particular punish-
ment, Atkins, supra, at 312 (quoting Coker, 433 U. S., at 597
(plurality opinion)). This judgment is not merely a rubber
stamp on the tally of legislative and jury actions. Rather,
it is an integral part of the Eighth Amendment inquiry—and
one that is entitled to independent weight in reaching our
ultimate decision.
Here, as in Atkins, the objective evidence of a national
consensus is weaker than in most prior cases in which the
Court has struck down a particular punishment under the
Eighth Amendment. See Coker, supra, at 595–596 (plural-
ity opinion) (striking down death penalty for rape of an adult

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woman, where only one jurisdiction authorized such punish-
ment); Enmund, 458 U. S., at 792 (striking down death pen-
alty for certain crimes of aiding and abetting felony-murder,
where only eight jurisdictions authorized such punishment);
Ford v. Wainwright, 477 U. S., at 408 (striking down capital
punishment of the insane, where no jurisdiction permitted
this practice). In my view, the objective evidence of na-
tional consensus, standing alone, was insufficient to dictate
the Court’s holding in Atkins. Rather, the compelling moral
proportionality argument against capital punishment of men-
tally retarded offenders played a decisive role in persuading
the Court that the practice was inconsistent with the Eighth
Amendment. Indeed, the force of the proportionality argu-
ment in Atkins significantly bolstered the Court’s confidence
that the objective evidence in that case did, in fact, herald
the emergence of a genuine national consensus. Here, by
contrast, the proportionality argument against the juvenile
death penalty is so flawed that it can be given little, if any,
analytical weight—it proves too weak to resolve the linger-
ing ambiguities in the objective evidence of legislative con-
sensus or to justify the Court’s categorical rule.
C
Seventeen-year-old murderers must be categorically ex-
empted from capital punishment, the Court says, because
they “cannot with reliability be classified among the worst
offenders.” Ante, at 569. That conclusion is premised on
three perceived differences between “adults,” who have al-
ready reached their 18th birthdays, and “juveniles,” who
have not. See ante, at 569–570. First, juveniles lack matu-
rity and responsibility and are more reckless than adults.
Second, juveniles are more vulnerable to outside influences
because they have less control over their surroundings.
And third, a juvenile’s character is not as fully formed as
that of an adult. Based on these characteristics, the Court
determines that 17-year-old capital murderers are not as

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blameworthy as adults guilty of similar crimes; that 17-
year-olds are less likely than adults to be deterred by the
prospect of a death sentence; and that it is difficult to con-
clude that a 17-year-old who commits even the most heinous
of crimes is “irretrievably depraved.” Ante, at 570–572.
The Court suggests that “a rare case might arise in which a
juvenile offender has sufficient psychological maturity, and
at the same time demonstrates sufficient depravity, to merit
a sentence of death.” Ante, at 572. However, the Court
argues that a categorical age-based prohibition is justified as
a prophylactic rule because “[t]he differences between juve-
nile and adult offenders are too marked and well understood
to risk allowing a youthful person to receive the death pen-
alty despite insufficient culpability.” Ante, at 572–573.
It is beyond cavil that juveniles as a class are generally
less mature, less responsible, and less fully formed than
adults, and that these differences bear on juveniles’ com-
parative moral culpability. See, e. g., Johnson v. Texas, 509
U. S. 350, 367 (1993) (“There is no dispute that a defendant’s
youth is a relevant mitigating circumstance”); id., at 376
(O’Connor, J., dissenting) (“[T]he vicissitudes of youth bear
directly on the young offender’s culpability and responsibil-
ity for the crime”); Eddings, 455 U. S., at 115–116 (“Our his-
tory is replete with laws and judicial recognition that minors,
especially in their earlier years, generally are less mature
and responsible than adults”). But even accepting this
premise, the Court’s proportionality argument fails to sup-
port its categorical rule.
First, the Court adduces no evidence whatsoever in sup-
port of its sweeping conclusion, see ante, at 572, that it is
only in “rare” cases, if ever, that 17-year-old murderers are
sufficiently mature and act with sufficient depravity to war-
rant the death penalty. The fact that juveniles are gener-
ally less culpable for their misconduct than adults does not
necessarily mean that a 17-year-old murderer cannot be suf-
ficiently culpable to merit the death penalty. At most, the

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Court’s argument suggests that the average 17-year-old
murderer is not as culpable as the average adult murderer.
But an especially depraved juvenile offender may neverthe-
less be just as culpable as many adult offenders considered
bad enough to deserve the death penalty. Similarly, the fact
that the availability of the death penalty may be less likely
to deter a juvenile from committing a capital crime does not
imply that this threat cannot effectively deter some 17-year-
olds from such an act. Surely there is an age below which
no offender, no matter what his crime, can be deemed to have
the cognitive or emotional maturity necessary to warrant the
death penalty. But at least at the margins between adoles-
cence and adulthood—and especially for 17-year-olds such as
respondent—the relevant differences between “adults” and
“juveniles” appear to be a matter of degree, rather than of
kind. It follows that a legislature may reasonably conclude
that at least some 17-year-olds can act with sufficient moral
culpability, and can be sufficiently deterred by the threat of
execution, that capital punishment may be warranted in an
appropriate case.
Indeed, this appears to be just such a case. Christopher
Simmons’ murder of Shirley Crook was premeditated, wan-
ton, and cruel in the extreme. Well before he committed
this crime, Simmons declared that he wanted to kill someone.
On several occasions, he discussed with two friends (ages 15
and 16) his plan to burglarize a house and to murder the
victim by tying the victim up and pushing him from a bridge.
Simmons said they could “ ‘get away with it’ ” because they
were minors. Brief for Petitioner 3. In accord with this
plan, Simmons and his 15-year-old accomplice broke into
Mrs. Crook’s home in the middle of the night, forced her from
her bed, bound her, and drove her to a state park. There,
they walked her to a railroad trestle spanning a river, “hog-
tied” her with electrical cable, bound her face completely
with duct tape, and pushed her, still alive, from the trestle.
She drowned in the water below. Id., at 4. One can

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scarcely imagine the terror that this woman must have suf-
fered throughout the ordeal leading to her death. Whatever
can be said about the comparative moral culpability of 17-
year-olds as a general matter, Simmons’ actions unquestion-
ably reflect “ ‘a consciousness materially more “depraved”
than that of ’ . . . the average murderer.” Atkins, 536 U. S.,
at 319 (quoting Godfrey v. Georgia, 446 U. S. 420, 433 (1980)).
And Simmons’ prediction that he could murder with impu-
nity because he had not yet turned 18—though inaccurate—
suggests that he did take into account the perceived risk
of punishment in deciding whether to commit the crime.
Based on this evidence, the sentencing jury certainly had
reasonable grounds for concluding that, despite Simmons’
youth, he “ha[d] sufficient psychological maturity” when
he committed this horrific murder, and “at the same time
demonstrate[d] sufficient depravity, to merit a sentence of
death.” Ante, at 572.
The Court’s proportionality argument suffers from a sec-
ond and closely related defect: It fails to establish that the
differences in maturity between 17-year-olds and young
“adults” are both universal enough and significant enough to
justify a bright-line prophylactic rule against capital punish-
ment of the former. The Court’s analysis is premised on
differences in the aggregate between juveniles and adults,
which frequently do not hold true when comparing individu-
als. Although it may be that many 17-year-old murderers
lack sufficient maturity to deserve the death penalty, some
juvenile murderers may be quite mature. Chronological age
is not an unfailing measure of psychological development,
and common experience suggests that many 17-year-olds are
more mature than the average young “adult.” In short, the
class of offenders exempted from capital punishment by
today’s decision is too broad and too diverse to warrant a
categorical prohibition. Indeed, the age-based line drawn
by the Court is indefensibly arbitrary—it quite likely will
protect a number of offenders who are mature enough to

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deserve the death penalty and may well leave vulnerable
many who are not.
For purposes of proportionality analysis, 17-year-olds as
a class are qualitatively and materially different from the
mentally retarded. “Mentally retarded” offenders, as we
understood that category in Atkins, are defined by precisely
the characteristics which render death an excessive punish-
ment. A mentally retarded person is, “by definition,” one
whose cognitive and behavioral capacities have been proved
to fall below a certain minimum. See Atkins, 536 U. S., at
318; see also id., at 308, n. 3 (discussing characteristics of
mental retardation); id., at 317, and n. 22 (leaving to the
States the development of mechanisms to determine which
offenders fall within the class exempt from capital punish-
ment). Accordingly, for purposes of our decision in Atkins,
the mentally retarded are not merely less blameworthy for
their misconduct or less likely to be deterred by the death
penalty than others. Rather, a mentally retarded offender
is one whose demonstrated impairments make it so highly
unlikely that he is culpable enough to deserve the death pen-
alty or that he could have been deterred by the threat of
death, that execution is not a defensible punishment. There
is no such inherent or accurate fit between an offender’s
chronological age and the personal limitations which the
Court believes make capital punishment excessive for 17-
year-old murderers. Moreover, it defies common sense to
suggest that 17-year-olds as a class are somehow equivalent
to mentally retarded persons with regard to culpability or
susceptibility to deterrence. Seventeen-year-olds may, on
average, be less mature than adults, but that lesser maturity
simply cannot be equated with the major, lifelong impair-
ments suffered by the mentally retarded.
The proportionality issues raised by the Court clearly im-
plicate Eighth Amendment concerns. But these concerns
may properly be addressed not by means of an arbitrary,
categorical age-based rule, but rather through individualized

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sentencing in which juries are required to give appropriate
mitigating weight to the defendant’s immaturity, his suscep-
tibility to outside pressures, his cognizance of the conse-
quences of his actions, and so forth. In that way the consti-
tutional response can be tailored to the specific problem it is
meant to remedy. The Eighth Amendment guards against
the execution of those who are “insufficient[ly] culpab[le],”
see ante, at 573, in significant part, by requiring sentencing
that “reflect[s] a reasoned moral response to the defendant’s
background, character, and crime.” California v. Brown,
479 U. S. 538, 545 (1987) (O’Connor, J., concurring). Ac-
cordingly, the sentencer in a capital case must be permitted
to give full effect to all constitutionally relevant mitigating
evidence. See Tennard v. Dretke, 542 U. S. 274, 283–285
(2004); Lockett v. Ohio, 438 U. S. 586, 604 (1978) (plurality
opinion). A defendant’s youth or immaturity is, of course, a
paradigmatic example of such evidence. See Eddings, 455
U. S., at 115–116.
Although the prosecutor’s apparent attempt to use re-
spondent’s youth as an aggravating circumstance in this case
is troubling, that conduct was never challenged with speci-
ficity in the lower courts and is not directly at issue here.
As the Court itself suggests, such “overreaching” would best
be addressed, if at all, through a more narrowly tailored rem-
edy. See ante, at 573. The Court argues that sentencing
juries cannot accurately evaluate a youthful offender’s matu-
rity or give appropriate weight to the mitigating characteris-
tics related to youth. But, again, the Court presents no real
evidence—and the record appears to contain none—support-
ing this claim. Perhaps more importantly, the Court fails to
explain why this duty should be so different from, or so much
more difficult than, that of assessing and giving proper effect
to any other qualitative capital sentencing factor. I would
not be so quick to conclude that the constitutional safe-
guards, the sentencing juries, and the trial judges upon

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which we place so much reliance in all capital cases are inad-
equate in this narrow context.
D
I turn, finally, to the Court’s discussion of foreign and in-
ternational law. Without question, there has been a global
trend in recent years toward abolishing capital punishment
for under-18 offenders. Very few, if any, countries other
than the United States now permit this practice in law or in
fact. See ante, at 576–577. While acknowledging that the
actions and views of other countries do not dictate the out-
come of our Eighth Amendment inquiry, the Court asserts
that “the overwhelming weight of international opinion
against the juvenile death penalty . . . does provide respected
and significant confirmation for [its] own conclusions. ”
Ante, at 578. Because I do not believe that a genuine na-
tional consensus against the juvenile death penalty has yet
developed, and because I do not believe the Court’s moral
proportionality argument justifies a categorical, age-based
constitutional rule, I can assign no such confirmatory role
to the international consensus described by the Court. In
short, the evidence of an international consensus does not
alter my determination that the Eighth Amendment does
not, at this time, forbid capital punishment of 17-year-old
murderers in all cases.
Nevertheless, I disagree with Justice Scalia’s conten-
tion, post, at 622–628 (dissenting opinion), that foreign and
international law have no place in our Eighth Amendment
jurisprudence. Over the course of nearly half a century, the
Court has consistently referred to foreign and international
law as relevant to its assessment of evolving standards of
decency. See Atkins, supra, at 317, n. 21; Thompson, 487
U. S., at 830–831, and n. 31 (plurality opinion); Enmund, 458
U. S., at 796–797, n. 22; Coker, 433 U. S., at 596, n. 10 (plural-
ity opinion); Trop, 356 U. S., at 102–103 (plurality opinion).
This inquiry reflects the special character of the Eighth

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605 Cite as: 543 U. S. 551 (2005)
O’Connor, J., dissenting
Amendment, which, as the Court has long held, draws its
meaning directly from the maturing values of civilized soci-
ety. Obviously, American law is distinctive in many re-
spects, not least where the specific provisions of our Consti-
tution and the history of its exposition so dictate. Cf. post,
at 624–625 (Scalia, J., dissenting) (discussing distinctively
American rules of law related to the Fourth Amendment
and the Establishment Clause). But this Nation’s evolving
understanding of human dignity certainly is neither wholly
isolated from, nor inherently at odds with, the values prevail-
ing in other countries. On the contrary, we should not be
surprised to find congruence between domestic and interna-
tional values, especially where the international community
has reached clear agreement—expressed in international law
or in the domestic laws of individual countries—that a partic-
ular form of punishment is inconsistent with fundamental
human rights. At least, the existence of an international
consensus of this nature can serve to confirm the reasonable-
ness of a consonant and genuine American consensus. The
instant case presents no such domestic consensus, however,
and the recent emergence of an otherwise global consensus
does not alter that basic fact.
* * *
In determining whether the Eighth Amendment permits
capital punishment of a particular offense or class of offend-
ers, we must look to whether such punishment is consistent
with contemporary standards of decency. We are obligated
to weigh both the objective evidence of societal values and
our own judgment as to whether death is an excessive sanc-
tion in the context at hand. In the instant case, the objec-
tive evidence is inconclusive; standing alone, it does not dem-
onstrate that our society has repudiated capital punishment
of 17-year-old offenders in all cases. Rather, the actions of
the Nation’s legislatures suggest that, although a clear and
durable national consensus against this practice may in time

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606 ROPER v. SIMMONS
O’Connor, J., dissenting
emerge, that day has yet to arrive. By acting so soon after
our decision in Stanford, the Court both pre-empts the dem-
ocratic debate through which genuine consensus might de-
velop and simultaneously runs a considerable risk of invit-
ing lower court reassessments of our Eighth Amendment
precedents.
To be sure, the objective evidence supporting today’s deci-
sion is similar to (though marginally weaker than) the evi-
dence before the Court in Atkins. But Atkins could not
have been decided as it was based solely on such evidence.
Rather, the compelling proportionality argument against
capital punishment of the mentally retarded played a deci-
sive role in the Court’s Eighth Amendment ruling. More-
over, the constitutional rule adopted in Atkins was tailored
to this proportionality argument: It exempted from capital
punishment a defined group of offenders whose proven im-
pairments rendered it highly unlikely, and perhaps impossi-
ble, that they could act with the degree of culpability neces-
sary to deserve death. And Atkins left to the States the
development of mechanisms to determine which individual
offenders fell within this class.
In the instant case, by contrast, the moral proportionality
arguments against the juvenile death penalty fail to support
the rule the Court adopts today. There is no question that
“the chronological age of a minor is itself a relevant mitigat-
ing factor of great weight,” Eddings, 455 U. S., at 116, and
that sentencing juries must be given an opportunity care-
fully to consider a defendant’s age and maturity in deciding
whether to assess the death penalty. But the mitigating
characteristics associated with youth do not justify an abso-
lute age limit. A legislature can reasonably conclude, as
many have, that some 17-year-old murderers are mature
enough to deserve the death penalty in an appropriate case.
And nothing in the record before us suggests that sentencing
juries are so unable accurately to assess a 17-year-old de-

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607 Cite as: 543 U. S. 551 (2005)
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fendant’s maturity, or so incapable of giving proper weight
to youth as a mitigating factor, that the Eighth Amendment
requires the bright-line rule imposed today. In the end, the
Court’s flawed proportionality argument simply cannot bear
the weight the Court would place upon it.
Reasonable minds can differ as to the minimum age at
which commission of a serious crime should expose the de-
fendant to the death penalty, if at all. Many jurisdictions
have abolished capital punishment altogether, while many
others have determined that even the most heinous crime, if
committed before the age of 18, should not be punishable by
death. Indeed, were my office that of a legislator, rather
than a judge, then I, too, would be inclined to support legisla-
tion setting a minimum age of 18 in this context. But a
significant number of States, including Missouri, have de-
cided to make the death penalty potentially available for 17-
year-old capital murderers such as respondent. Without a
clearer showing that a genuine national consensus forbids
the execution of such offenders, this Court should not substi-
tute its own “inevitably subjective judgment” on how best
to resolve this difficult moral question for the judgments
of the Nation’s democratically elected legislatures. See
Thompson, 487 U. S., at 854 (O’Connor, J., concurring in
judgment). I respectfully dissent.
Justice Scalia, with whom The Chief Justice and
Justice Thomas join, dissenting.
In urging approval of a constitution that gave life-tenured
judges the power to nullify laws enacted by the people’s rep-
resentatives, Alexander Hamilton assured the citizens of
New York that there was little risk in this, since “[t]he judi-
ciary . . . ha[s] neither FORCE nor WILL but merely judg-
ment.” The Federalist No. 78, p. 465 (C. Rossiter ed. 1961).
But Hamilton had in mind a traditional judiciary, “bound
down by strict rules and precedents which serve to define

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608 ROPER v. SIMMONS
Scalia, J., dissenting
and point out their duty in every particular case that comes
before them.” Id., at 471. Bound down, indeed. What a
mockery today’s opinion makes of Hamilton’s expectation,
announcing the Court’s conclusion that the meaning of our
Constitution has changed over the past 15 years—not, mind
you, that this Court’s decision 15 years ago was wrong, but
that the Constitution has changed. The Court reaches this
implausible result by purporting to advert, not to the origi-
nal meaning of the Eighth Amendment, but to “the evolving
standards of decency,” ante, at 561 (internal quotation marks
omitted), of our national society. It then finds, on the flim-
siest of grounds, that a national consensus which could not
be perceived in our people’s laws barely 15 years ago now
solidly exists. Worse still, the Court says in so many words
that what our people’s laws say about the issue does not, in
the last analysis, matter: “[I]n the end our own judgment
will be brought to bear on the question of the acceptability
of the death penalty under the Eighth Amendment.” Ante,
at 563 (internal quotation marks omitted). The Court thus
proclaims itself sole arbiter of our Nation’s moral stand-
ards—and in the course of discharging that awesome respon-
sibility purports to take guidance from the views of foreign
courts and legislatures. Because I do not believe that the
meaning of our Eighth Amendment, any more than the
meaning of other provisions of our Constitution, should be
determined by the subjective views of five Members of this
Court and like-minded foreigners, I dissent.
I
In determining that capital punishment of offenders who
committed murder before age 18 is “cruel and unusual”
under the Eighth Amendment, the Court first considers, in
accordance with our modern (though in my view mistaken)
jurisprudence, whether there is a “national consensus,” ibid.
(internal quotation marks omitted), that laws allowing such

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609 Cite as: 543 U. S. 551 (2005)
Scalia, J., dissenting
executions contravene our modern “standards of decency,” 1
Trop v. Dulles, 356 U. S. 86, 101 (1958). We have held that
this determination should be based on “objective indicia that
reflect the public attitude toward a given sanction”—namely,
“statutes passed by society’s elected representatives. ”
Stanford v. Kentucky, 492 U. S. 361, 370 (1989) (internal quo-
tation marks omitted). As in Atkins v. Virginia, 536 U. S.
304, 312 (2002), the Court dutifully recites this test and
claims halfheartedly that a national consensus has emerged
since our decision in Stanford, because 18 States—or 47% of
States that permit capital punishment—now have legislation
prohibiting the execution of offenders under 18, and because
all of 4 States have adopted such legislation since Stanford.
See ante, at 565.
Words have no meaning if the views of less than 50% of
death penalty States can constitute a national consensus.
See Atkins, supra, at 342–345 (Scalia, J., dissenting). Our
previous cases have required overwhelming opposition to a
challenged practice, generally over a long period of time. In
Coker v. Georgia, 433 U. S. 584, 595–596 (1977), a plurality
concluded the Eighth Amendment prohibited capital punish-
ment for rape of an adult woman where only one jurisdiction
authorized such punishment. The plurality also observed
that “[a]t no time in the last 50 years ha[d] a majority of
1 The Court ignores entirely the threshold inquiry in determining
whether a particular punishment complies with the Eighth Amendment:
whether it is one of the “modes or acts of punishment that had been consid-
ered cruel and unusual at the time that the Bill of Rights was adopted.”
Ford v. Wainwright, 477 U. S. 399, 405 (1986). As we have noted in prior
cases, the evidence is unusually clear that the Eighth Amendment was not
originally understood to prohibit capital punishment for 16- and 17-year-
old offenders. See Stanford v. Kentucky, 492 U. S. 361, 368 (1989). At
the time the Eighth Amendment was adopted, the death penalty could
theoretically be imposed for the crime of a 7-year-old, though there was a
rebuttable presumption of incapacity to commit a capital (or other) felony
until the age of 14. See ibid. (citing 4 W. Blackstone, Commentaries *23–
*24; 1 M. Hale, Pleas of the Crown 24–29 (1800)).

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610 ROPER v. SIMMONS
Scalia, J., dissenting
States authorized death as a punishment for rape.” Id., at
593. In Ford v. Wainwright, 477 U. S. 399, 408 (1986), we
held execution of the insane unconstitutional, tracing the
roots of this prohibition to the common law and noting that
“no State in the union permits the execution of the insane.”
In Enmund v. Florida, 458 U. S. 782, 792 (1982), we invali-
dated capital punishment imposed for participation in a rob-
bery in which an accomplice committed murder, because 78%
of all death penalty States prohibited this punishment.
Even there we expressed some hesitation, because the legis-
lative judgment was “neither ‘wholly unanimous among state
legislatures,’ . . . nor as compelling as the legislative judg-
ments considered in Coker. ” Id., at 793. By contrast,
agreement among 42% of death penalty States in Stanford,
which the Court appears to believe was correctly decided at
the time, ante, at 574, was insufficient to show a national
consensus. See Stanford, supra, at 372.
In an attempt to keep afloat its implausible assertion of
national consensus, the Court throws overboard a proposi-
tion well established in our Eighth Amendment jurispru-
dence. “It should be observed,” the Court says, “that the
Stanford Court should have considered those States that had
abandoned the death penalty altogether as part of the
consensus against the juvenile death penalty . . . ; a State’s
decision to bar the death penalty altogether of necessity
demonstrates a judgment that the death penalty is inappro-
priate for all offenders, including juveniles.” Ante, at 574.
The insinuation that the Court’s new method of counting con-
tradicts only “the Stanford Court” is misleading. None of
our cases dealing with an alleged constitutional limitation
upon the death penalty has counted, as States supporting a
consensus in favor of that limitation, States that have elimi-
nated the death penalty entirely. See Ford, supra, at 408,
n. 2; Enmund, supra, at 789; Coker, supra, at 594. And with
good reason. Consulting States that bar the death penalty
concerning the necessity of making an exception to the pen-

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611 Cite as: 543 U. S. 551 (2005)
Scalia, J., dissenting
alty for offenders under 18 is rather like including old-order
Amishmen in a consumer-preference poll on the electric car.
Of course they don’t like it, but that sheds no light whatever
on the point at issue. That 12 States favor no executions
says something about consensus against the death penalty,
but nothing—absolutely nothing—about consensus that
offenders under 18 deserve special immunity from such a
penalty. In repealing the death penalty, those 12 States
considered none of the factors that the Court puts forth as
determinative of the issue before us today—lower culpability
of the young, inherent recklessness, lack of capacity for con-
sidered judgment, etc. What might be relevant, perhaps, is
how many of those States permit 16- and 17-year-old offend-
ers to be treated as adults with respect to noncapital of-
fenses. (They all do; 2 indeed, some even require that juve-
niles as young as 14 be tried as adults if they are charged
with murder.3 ) The attempt by the Court to turn its re-
markable minority consensus into a faux majority by count-
ing Amishmen is an act of nomological desperation.
Recognizing that its national-consensus argument was
weak compared with our earlier cases, the Atkins Court
found additional support in the fact that 16 States had pro-
hibited execution of mentally retarded individuals since
2 See Alaska Stat. § 47.12.030 (Lexis 2002); Haw. Rev. Stat. § 571–22
(1999); Iowa Code § 232.45 (2003); Me. Rev. Stat. Ann., Tit. 15, § 3101(4)
(West 2003); Mass. Gen. Laws Ann., ch. 119, § 74 (West 2003); Mich. Comp.
Laws Ann. § 764.27 (West 2000); Minn. Stat. § 260B.125 (2004); N. D. Cent.
Code § 27–20–34 (Lexis Supp. 2003); R. I. Gen. Laws § 14–1–7 (Lexis 2002);
Vt. Stat. Ann., Tit. 33, § 5516 (Lexis 2001); W. Va. Code § 49–5–10 (Lexis
2004); Wis. Stat. § 938.18 (2003–2004); see also National Center for Juvenile
Justice, Trying and Sentencing Juveniles as Adults: An Analysis of State
Transfer and Blended Sentencing Laws 1 (Oct. 2003). The District of
Columbia is the only jurisdiction without a death penalty that specifically
exempts under-18 offenders from its harshest sanction—life imprisonment
without parole. See D. C. Code § 22–2104 (West 2001).
3 See Mass. Gen. Laws Ann., ch. 119, § 74 (West 2003); N. D. Cent. Code
§ 27–20–34 (Lexis Supp. 2003); W. Va. Code § 49–5–10 (Lexis 2004).

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612 ROPER v. SIMMONS
Scalia, J., dissenting
Penry v. Lynaugh, 492 U. S. 302 (1989). Atkins, 536 U. S.,
at 314–316. Indeed, the Atkins Court distinguished Stan-
ford on that very ground, explaining that “[a]lthough we de-
cided Stanford on the same day as Penry, apparently only
two state legislatures have raised the threshold age for impo-
sition of the death penalty.” 536 U. S., at 315, n. 18 (empha-
sis added). Now, the Court says a legislative change in four
States is “significant” enough to trigger a constitutional pro-
hibition.4 Ante, at 566. It is amazing to think that this
subtle shift in numbers can take the issue entirely off the
table for legislative debate.
I also doubt whether many of the legislators who voted to
change the laws in those four States would have done so if
they had known their decision would (by the pronouncement
of this Court) be rendered irreversible. After all, legislative
support for capital punishment, in any form, has surged
and ebbed throughout our Nation’s history. As Justice
O’Connor has explained:
“The history of the death penalty instructs that there
is danger in inferring a settled societal consensus from
statistics like those relied on in this case. In 1846,
Michigan became the first State to abolish the death
penalty . . . . In succeeding decades, other American
States continued the trend towards abolition . . . .
Later, and particularly after World War II, there ensued
a steady and dramatic decline in executions . . . . In
the 1950’s and 1960’s, more States abolished or radically
restricted capital punishment, and executions ceased
completely for several years beginning in 1968. . . .
4 As the Court notes, Washington State’s decision to prohibit executions
of offenders under 18 was made by a judicial, not legislative, decision.
State v. Furman, 122 Wash. 2d 440, 459, 858 P. 2d 1092, 1103 (1993), con-
strued the State’s death penalty statute—which did not set any age
limit—to apply only to persons over 18. The opinion found that construc-
tion necessary to avoid what it considered constitutional difficulties, and
did not purport to reflect popular sentiment. It is irrelevant to the ques-
tion of changed national consensus.

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Scalia, J., dissenting
“In 1972, when this Court heard arguments on the
constitutionality of the death penalty, such statistics
might have suggested that the practice had become a
relic, implicitly rejected by a new societal consensus. . . .
We now know that any inference of a societal consensus
rejecting the death penalty would have been mistaken.
But had this Court then declared the existence of such
a consensus, and outlawed capital punishment, legisla-
tures would very likely not have been able to revive it.
The mistaken premise of the decision would have been
frozen into constitutional law, making it difficult to re-
fute and even more difficult to reject.” Thompson v.
Oklahoma, 487 U. S. 815, 854–855 (1988) (opinion concur-
ring in judgment).
Relying on such narrow margins is especially inappropri-
ate in light of the fact that a number of legislatures and
voters have expressly affirmed their support for capital pun-
ishment of 16- and 17-year-old offenders since Stanford.
Though the Court is correct that no State has lowered its
death penalty age, both the Missouri and Virginia Legisla-
tures—which, at the time of Stanford, had no minimum age
requirement—expressly established 16 as the minimum.
Mo. Rev. Stat. § 565.020.2 (2000); Va. Code Ann. § 18.2–10(a)
(Lexis 2004). The people of Arizona 5 and Florida 6 have
5 In 1996, Arizona’s Ballot Proposition 102 exposed under-18 murderers
to the death penalty by automatically transferring them out of juvenile
courts. The statute implementing the proposition required the county
attorney to “bring a criminal prosecution against a juvenile in the same
manner as an adult if the juvenile is fifteen, sixteen or seventeen years of
age and is accused of . . . first degree murder.” Ariz. Rev. Stat. Ann.
§ 13–501 (West 2001). The Arizona Supreme Court has added to this
scheme a constitutional requirement that there be an individualized as-
sessment of the juvenile’s maturity at the time of the offense. See State
v. Davolt, 207 Ariz. 191, 214–216, 84 P. 3d 456, 479–481 (2004).
6 Florida voters approved an amendment to the State Constitution,
which changed the wording from “cruel or unusual” to “cruel and un-
usual,” Fla. Const., Art. I, § 17 (2003). See Commentary to 1998 Amend-
ment, 25B Fla. Stat. Ann., p. 180 (West 2004). This was a response to a

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614 ROPER v. SIMMONS
Scalia, J., dissenting
done the same by ballot initiative. Thus, even States that
have not executed an under-18 offender in recent years un-
questionably favor the possibility of capital punishment in
some circumstances.
The Court’s reliance on the infrequency of executions for
under-18 murderers, ante, at 564–565, 567, credits an argu-
ment that this Court considered and explicitly rejected in
Stanford. That infrequency is explained, we accurately
said, both by “the undisputed fact that a far smaller percent-
age of capital crimes are committed by persons under 18 than
over 18,” 492 U. S., at 374, and by the fact that juries are
required at sentencing to consider the offender’s youth as a
mitigating factor, see Eddings v. Oklahoma, 455 U. S. 104,
115–116 (1982). Thus, “it is not only possible, but over-
whelmingly probable, that the very considerations which in-
duce [respondent] and [his] supporters to believe that death
should never be imposed on offenders under 18 cause prose-
cutors and juries to believe that it should rarely be imposed.”
Stanford, supra, at 374.
It is, furthermore, unclear that executions of the relevant
age group have decreased since we decided Stanford. Be-
tween 1990 and 2003, 123 of 3,599 death sentences, or 3.4%,
were given to individuals who committed crimes before
reaching age 18. V. Streib, The Juvenile Death Penalty
Today: Death Sentences and Executions for Juvenile Crimes,
January 1, 1973–September 30, 2004, No. 75, p. 9 (Table 3)
(last updated Oct. 5, 2004), http://www.law.onu.edu/faculty/
streib/documents/JuvDeathSept302004.pdf (all Internet ma-
terials as visited Jan. 12, 2005, and available in Clerk of
Court’s case file) (hereinafter Juvenile Death Penalty Today).
Florida Supreme Court ruling that “cruel or unusual” excluded the death
penalty for a defendant who committed murder when he was younger than
17. See Brennan v. State, 754 So. 2d 1, 5 (1999). By adopting the federal
constitutional language, Florida voters effectively adopted our decision in
Stanford v. Kentucky, 492 U. S. 361 (1989). See Weaver, Word May Allow
Execution of 16-Year-Olds, Miami Herald, Nov. 7, 2002, p. 7B.

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By contrast, only 2.1% of those sentenced to death between
1982 and 1988 committed the crimes when they were under
18. See Stanford, supra, at 373 (citing V. Streib, Imposition
of Death Sentences for Juvenile Offenses, January 1, 1982,
Through April 1, 1989, p. 2 (paper for Cleveland-Marshall
College of Law, April 5, 1989)). As for actual executions of
under-18 offenders, they constituted 2.4% of the total exe-
cutions since 1973. Juvenile Death Penalty Today 4. In
Stanford, we noted that only 2% of the executions between
1642 and 1986 were of under-18 offenders and found that that
lower number did not demonstrate a national consensus
against the penalty. 492 U. S., at 373–374 (citing V. Streib,
Death Penalty for Juveniles 55, 57 (1987)). Thus, the num-
bers of under-18 offenders subjected to the death penalty,
though low compared with adults, have either held steady or
slightly increased since Stanford. These statistics in no
way support the action the Court takes today.
II
Of course, the real force driving today’s decision is not the
actions of four state legislatures, but the Court’s “ ‘ “own
judgment” ’ ” that murderers younger than 18 can never be
as morally culpable as older counterparts. Ante, at 563
(quoting Atkins, 536 U. S., at 312 (in turn quoting Coker, 433
U. S., at 597 (plurality opinion))). The Court claims that this
usurpation of the role of moral arbiter is simply a “retur[n]
to the rul[e] established in decisions predating Stanford,”
ante, at 563. That supposed rule—which is reflected solely
in dicta and never once in a holding that purports to sup-
plant the consensus of the American people with the Justices’
views 7
—was repudiated in Stanford for the very good rea-
7 See, e. g., Enmund v. Florida, 458 U. S. 782, 801 (1982) (“[W]e have no
reason to disagree with th[e] judgment [of the state legislatures] for pur-
poses of construing and applying the Eighth Amendment”); Coker v. Geor-
gia, 433 U. S. 584, 597 (1977) (plurality opinion) (“[T]he legislative rejec-
tion of capital punishment for rape strongly confirms our own judgment”).

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son that it has no foundation in law or logic. If the Eighth
Amendment set forth an ordinary rule of law, it would indeed
be the role of this Court to say what the law is. But the
Court having pronounced that the Eighth Amendment is an
ever-changing reflection of “the evolving standards of de-
cency” of our society, it makes no sense for the Justices then
to prescribe those standards rather than discern them from
the practices of our people. On the evolving-standards hy-
pothesis, the only legitimate function of this Court is to iden-
tify a moral consensus of the American people. By what
conceivable warrant can nine lawyers presume to be the au-
thoritative conscience of the Nation? 8
The reason for insistence on legislative primacy is obvious
and fundamental: “ ‘[I]n a democratic society legislatures, not
courts, are constituted to respond to the will and conse-
quently the moral values of the people.’ ” Gregg v. Georgia,
428 U. S. 153, 175–176 (1976) ( joint opinion of Stewart, Pow-
ell, and Stevens, JJ.) (quoting Furman v. Georgia, 408 U. S.
238, 383 (1972) (Burger, C. J., dissenting)). For a similar rea-
son we have, in our determination of society’s moral stand-
ards, consulted the practices of sentencing juries: Juries
“ ‘maintain a link between contemporary community values
and the penal system’ ” that this Court cannot claim for itself.
Gregg, supra, at 181 (quoting Witherspoon v. Illinois, 391
U. S. 510, 519, n. 15 (1968)).
Today’s opinion provides a perfect example of why judges
are ill equipped to make the type of legislative judgments
the Court insists on making here. To support its opinion
that States should be prohibited from imposing the death
8 Justice O’Connor agrees with our analysis that no national consensus
exists here, ante, at 594–598 (dissenting opinion). She is nonetheless pre-
pared (like the majority) to override the judgment of America’s legisla-
tures if it contradicts her own assessment of “moral proportionality,” ante,
at 598. She dissents here only because it does not. The votes in today’s
case demonstrate that the offending of selected lawyers’ moral sentiments
is not a predictable basis for law—much less a democratic one.

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penalty on anyone who committed murder before age 18, the
Court looks to scientific and sociological studies, picking and
choosing those that support its position. It never explains
why those particular studies are methodologically sound;
none was ever entered into evidence or tested in an adver-
sarial proceeding. As The Chief Justice has explained:
“[M]ethodological and other errors can affect the relia-
bility and validity of estimates about the opinions and
attitudes of a population derived from various sampling
techniques. Everything from variations in the survey
methodology, such as the choice of the target population,
the sampling design used, the questions asked, and the
statistical analyses used to interpret the data can skew
the results.” Atkins, supra, at 326–327 (dissenting
opinion) (citing R. Groves, Survey Errors and Survey
Costs (1989); 1 C. Turner & E. Martin, Surveying Sub-
jective Phenomena (1984)).
In other words, all the Court has done today, to borrow from
another context, is to look over the heads of the crowd and
pick out its friends. Cf. Conroy v. Aniskoff, 507 U. S. 511,
519 (1993) (Scalia, J., concurring in judgment).
We need not look far to find studies contradicting the
Court’s conclusions. As petitioner points out, the American
Psychological Association (APA), which claims in this case
that scientific evidence shows persons under 18 lack the abil-
ity to take moral responsibility for their decisions, has pre-
viously taken precisely the opposite position before this very
Court. In its brief in Hodgson v. Minnesota, 497 U. S. 417
(1990), the APA found a “rich body of research” showing that
juveniles are mature enough to decide whether to obtain an
abortion without parental involvement. Brief for APA as
Amicus Curiae, O. T. 1989, No. 88–805 etc., p. 18. The APA
brief, citing psychology treatises and studies too numerous
to list here, asserted: “[B]y middle adolescence (age 14–15)
young people develop abilities similar to adults in reasoning

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618 ROPER v. SIMMONS
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about moral dilemmas, understanding social rules and laws,
[and] reasoning about interpersonal relationships and in-
terpersonal problems.” Id., at 19–20 (citations omitted).
Given the nuances of scientific methodology and conflicting
views, courts—which can only consider the limited evidence
on the record before them—are ill equipped to determine
which view of science is the right one. Legislatures “are
better qualified to weigh and ‘evaluate the results of statisti-
cal studies in terms of their own local conditions and with a
flexibility of approach that is not available to the courts.’ ”
McCleskey v. Kemp, 481 U. S. 279, 319 (1987) (quoting Gregg,
supra, at 186).
Even putting aside questions of methodology, the studies
cited by the Court offer scant support for a categorical prohi-
bition of the death penalty for murderers under 18. At
most, these studies conclude that, on average, or in most
cases, persons under 18 are unable to take moral responsibil-
ity for their actions. Not one of the cited studies opines that
all individuals under 18 are unable to appreciate the nature
of their crimes.
Moreover, the cited studies describe only adolescents who
engage in risky or antisocial behavior, as many young people
do. Murder, however, is more than just risky or antisocial
behavior. It is entirely consistent to believe that young peo-
ple often act impetuously and lack judgment, but, at the
same time, to believe that those who commit premeditated
murder are—at least sometimes—just as culpable as adults.
Christopher Simmons, who was only seven months shy of his
18th birthday when he murdered Shirley Crook, described
to his friends beforehand—“[i]n chilling, callous terms,” as
the Court puts it, ante, at 556—the murder he planned to
commit. He then broke into the home of an innocent
woman, bound her with duct tape and electrical wire, and
threw her off a bridge alive and conscious. Ante, at 556–
557. In their amici brief, the States of Alabama, Delaware,
Oklahoma, Texas, Utah, and Virginia offer additional exam-

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ples of murders committed by individuals under 18 that in-
volve truly monstrous acts. In Alabama, two 17-year-olds,
one 16-year-old, and one 19-year-old picked up a female
hitchhiker, threw bottles at her, and kicked and stomped her
for approximately 30 minutes until she died. They then sex-
ually assaulted her lifeless body and, when they were fin-
ished, threw her body off a cliff. They later returned to the
crime scene to mutilate her corpse. See Brief for Alabama
et al. as Amici Curiae 9–10; see also Loggins v. State, 771
So. 2d 1070, 1074–1075 (Ala. Crim. App. 1999); Duncan v.
State, 827 So. 2d 838, 840–841 (Ala. Crim. App. 1999). Other
examples in the brief are equally shocking. Though these
cases are assuredly the exception rather than the rule, the
studies the Court cites in no way justify a constitutional im-
perative that prevents legislatures and juries from treating
exceptional cases in an exceptional way—by determining
that some murders are not just the acts of happy-go-lucky
teenagers, but heinous crimes deserving of death.
That “almost every State prohibits those under 18 years
of age from voting, serving on juries, or marrying without
parental consent,” ante, at 569, is patently irrelevant—and
is yet another resurrection of an argument that this Court
gave a decent burial in Stanford. (What kind of Equal Jus-
tice under Law is it that—without so much as a “Sorry about
that”—gives as the basis for sparing one person from execu-
tion arguments explicitly rejected in refusing to spare an-
other?) As we explained in Stanford, 492 U. S., at 374, it is
“absurd to think that one must be mature enough to drive
carefully, to drink responsibly, or to vote intelligently, in
order to be mature enough to understand that murdering
another human being is profoundly wrong, and to conform
one’s conduct to that most minimal of all civilized standards.”
Serving on a jury or entering into marriage also involve deci-
sions far more sophisticated than the simple decision not to
take another’s life.

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Moreover, the age statutes the Court lists “set the appro-
priate ages for the operation of a system that makes its de-
terminations in gross, and that does not conduct individual-
ized maturity tests.” Ibid. The criminal justice system, by
contrast, provides for individualized consideration of each
defendant. In capital cases, this Court requires the sen-
tencer to make an individualized determination, which in-
cludes weighing aggravating factors and mitigating factors,
such as youth. See Eddings, 455 U. S., at 115–117. In
other contexts where individualized consideration is pro-
vided, we have recognized that at least some minors will be
mature enough to make difficult decisions that involve moral
considerations. For instance, we have struck down abortion
statutes that do not allow minors deemed mature by courts
to bypass parental notification provisions. See, e. g., Bel-
lotti v. Baird, 443 U. S. 622, 643–644 (1979) (opinion of Pow-
ell, J.); Planned Parenthood of Central Mo. v. Danforth, 428
U. S. 52, 74–75 (1976). It is hard to see why this context
should be any different. Whether to obtain an abortion is
surely a much more complex decision for a young person than
whether to kill an innocent person in cold blood.
The Court concludes, however, ante, at 572–573, that ju-
ries cannot be trusted with the delicate task of weighing a
defendant’s youth along with the other mitigating and aggra-
vating factors of his crime. This startling conclusion under-
mines the very foundations of our capital sentencing sys-
tem, which entrusts juries with “mak[ing] the difficult and
uniquely human judgments that defy codification and that
‘buil[d] discretion, equity, and flexibility into a legal sys-
tem.’ ” McCleskey, supra, at 311 (quoting H. Kalven & H.
Zeisel, The American Jury 498 (1966)). The Court says,
ante, at 573, that juries will be unable to appreciate the sig-
nificance of a defendant’s youth when faced with details of a
brutal crime. This assertion is based on no evidence; to the
contrary, the Court itself acknowledges that the execution of
under-18 offenders is “infrequent” even in the States “with-

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out a formal prohibition on executing juveniles,” ante, at 564,
suggesting that juries take seriously their responsibility to
weigh youth as a mitigating factor.
Nor does the Court suggest a stopping point for its reason-
ing. If juries cannot make appropriate determinations in
cases involving murderers under 18, in what other kinds of
cases will the Court find jurors deficient? We have already
held that no jury may consider whether a mentally deficient
defendant can receive the death penalty, irrespective of his
crime. See Atkins, 536 U. S., at 321. Why not take other
mitigating factors, such as considerations of childhood abuse
or poverty, away from juries as well? Surely jurors “over-
power[ed]” by “the brutality or cold-blooded nature” of a
crime, ante, at 573, could not adequately weigh these mitigat-
ing factors either.
The Court’s contention that the goals of retribution and
deterrence are not served by executing murderers under 18
is also transparently false. The argument that “[r]etribu-
tion is not proportional if the law’s most severe penalty is
imposed on one whose culpability or blameworthiness is di-
minished,” ante, at 571, is simply an extension of the earlier,
false generalization that youth always defeats culpability.
The Court claims that “juveniles will be less susceptible to
deterrence,” ibid., because “ ‘[t]he likelihood that the teenage
offender has made the kind of cost-benefit analysis that at-
taches any weight to the possibility of execution is so remote
as to be virtually nonexistent,’ ” ante, at 572 (quoting
Thompson, 487 U. S., at 837). The Court unsurprisingly
finds no support for this astounding proposition, save its own
case law. The facts of this very case show the proposition
to be false. Before committing the crime, Simmons encour-
aged his friends to join him by assuring them that they could
“get away with it” because they were minors. State ex rel.
Simmons v. Roper, 112 S. W. 3d 397, 419 (Mo. 2003) (Price,
J., dissenting). This fact may have influenced the jury’s de-
cision to impose capital punishment despite Simmons’ age.

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622 ROPER v. SIMMONS
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Because the Court refuses to entertain the possibility that
its own unsubstantiated generalization about juveniles could
be wrong, it ignores this evidence entirely.
III
Though the views of our own citizens are essentially irrele-
vant to the Court’s decision today, the views of other coun-
tries and the so-called international community take center
stage.
The Court begins by noting that “Article 37 of the United
Nations Convention on the Rights of the Child, [1577
U. N. T. S. 3, 28 I. L. M. 1448, 1468–1470, entered into force
Sept. 2, 1990,] which every country in the world has ratified
save for the United States and Somalia, contains an express
prohibition on capital punishment for crimes committed by
juveniles under 18.” Ante, at 576 (emphasis added). The
Court also discusses the International Covenant on Civil and
Political Rights (ICCPR), December 19, 1966, 999 U. N. T. S.
175, ante, at 567, 576, which the Senate ratified only subject
to a reservation that reads:
“The United States reserves the right, subject to its
Constitutional constraints, to impose capital punishment
on any person (other than a pregnant woman) duly con-
victed under existing or future laws permitting the im-
position of capital punishment, including such punish-
ment for crimes committed by persons below eighteen
years of age.” Senate Committee on Foreign Relations,
International Covenant on Civil and Political Rights,
S. Exec. Rep. No. 102–23, p. 11 (1992).
Unless the Court has added to its arsenal the power to join
and ratify treaties on behalf of the United States, I cannot
see how this evidence favors, rather than refutes, its posi-
tion. That the Senate and the President—those actors our
Constitution empowers to enter into treaties, see Art. II,
§ 2—have declined to join and ratify treaties prohibiting

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execution of under-18 offenders can only suggest that our
country has either not reached a national consensus on the
question, or has reached a consensus contrary to what the
Court announces. That the reservation to the ICCPR was
made in 1992 does not suggest otherwise, since the reserva-
tion still remains in place today. It is also worth noting
that, in addition to barring the execution of under-18 offend-
ers, the United Nations Convention on the Rights of the
Child prohibits punishing them with life in prison without
the possibility of release. If we are truly going to get in
line with the international community, then the Court’s reas-
surance that the death penalty is really not needed, since
“the punishment of life imprisonment without the possibility
of parole is itself a severe sanction,” ante, at 572, gives lit-
tle comfort.
It is interesting that whereas the Court is not content to
accept what the States of our Federal Union say, but insists
on inquiring into what they do (specifically, whether they in
fact apply the juvenile death penalty that their laws allow),
the Court is quite willing to believe that every foreign na-
tion—of whatever tyrannical political makeup and with how-
ever subservient or incompetent a court system—in fact ad-
heres to a rule of no death penalty for offenders under 18.
Nor does the Court inquire into how many of the countries
that have the death penalty, but have forsworn (on paper at
least) imposing that penalty on offenders under 18, have
what no State of this country can constitutionally have: a
mandatory death penalty for certain crimes, with no possi-
bility of mitigation by the sentencing authority, for youth or
any other reason. I suspect it is most of them. See, e. g., R.
Simon & D. Blaskovich, A Comparative Analysis of Capital
Punishment: Statutes, Policies, Frequencies, and Public Atti-
tudes the World Over 25, 26, 29 (2002). To forbid the death
penalty for juveniles under such a system may be a good
idea, but it says nothing about our system, in which the sen-
tencing authority, typically a jury, always can, and almost

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624 ROPER v. SIMMONS
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always does, withhold the death penalty from an under-18
offender except, after considering all the circumstances, in
the rare cases where it is warranted. The foreign authori-
ties, in other words, do not even speak to the issue before
us here.
More fundamentally, however, the basic premise of the
Court’s argument—that American law should conform to the
laws of the rest of the world—ought to be rejected out of
hand. In fact the Court itself does not believe it. In many
significant respects the laws of most other countries differ
from our law—including not only such explicit provisions of
our Constitution as the right to jury trial and grand jury
indictment, but even many interpretations of the Constitu-
tion prescribed by this Court itself. The Court-pronounced
exclusionary rule, for example, is distinctively American.
When we adopted that rule in Mapp v. Ohio, 367 U. S. 643,
655 (1961), it was “unique to American jurisprudence.”
Bivens v. Six Unknown Fed. Narcotics Agents, 403 U. S. 388,
415 (1971) (Burger, C. J., dissenting). Since then a categori-
cal exclusionary rule has been “universally rejected” by
other countries, including those with rules prohibiting illegal
searches and police misconduct, despite the fact that none
of these countries “appears to have any alternative form of
discipline for police that is effective in preventing search vio-
lations.” Bradley, Mapp Goes Abroad, 52 Case W. Res.
L. Rev. 375, 399–400 (2001). England, for example, rarely
excludes evidence found during an illegal search or seizure
and has only recently begun excluding evidence from ille-
gally obtained confessions. See C. Slobogin, Criminal Pro-
cedure: Regulation of Police Investigation 550 (3d ed. 2002).
Canada rarely excludes evidence and will only do so if admis-
sion will “bring the administration of justice into disrepute.”
Id., at 550–551 (internal quotation marks omitted). The
European Court of Human Rights has held that introduction
of illegally seized evidence does not violate the “fair trial”
requirement in Article 6, § 1, of the European Convention on

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Human Rights. See Slobogin, supra, at 551; Bradley, supra,
at 377–378.
The Court has been oblivious to the views of other coun-
tries when deciding how to interpret our Constitution’s re-
quirement that “Congress shall make no law respecting an
establishment of religion . . . .” Amdt. 1. Most other coun-
tries—including those committed to religious neutrality—
do not insist on the degree of separation between church
and state that this Court requires. For example, whereas
“we have recognized special Establishment Clause dangers
where the government makes direct money payments to sec-
tarian institutions,” Rosenberger v. Rector and Visitors of
Univ. of Va., 515 U. S. 819, 842 (1995) (citing cases), countries
such as the Netherlands, Germany, and Australia allow di-
rect government funding of religious schools on the ground
that “the state can only be truly neutral between secular and
religious perspectives if it does not dominate the provision
of so key a service as education, and makes it possible for
people to exercise their right of religious expression within
the context of public funding.” S. Monsma & J. Soper, The
Challenge of Pluralism: Church and State in Five Democra-
cies 207 (1997); see also id., at 67, 103, 176. England permits
the teaching of religion in state schools. Id., at 142. Even
in France, which is considered “America’s only rival in strict-
ness of church-state separation,” “[t]he practice of contract-
ing for educational services provided by Catholic schools
is very widespread.” C. Glenn, The Ambiguous Embrace:
Government and Faith-Based Schools and Social Agencies
110 (2000).
And let us not forget the Court’s abortion jurisprudence,
which makes us one of only six countries that allow abortion
on demand until the point of viability. See Larsen, Im-
porting Constitutional Norms from a “Wider Civilization”:
Lawrence and the Rehnquist Court’s Use of Foreign and
International Law in Domestic Constitutional Interpreta-
tion, 65 Ohio St. L. J. 1283, 1320 (2004); Center for Reproduc-

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626 ROPER v. SIMMONS
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tive Rights, The World’s Abortion Laws (June 2004), http://
www.reproductiverights.org/pub_fac_abortion_laws.html.
Though the Government and amici in cases following Roe
v. Wade, 410 U. S. 113 (1973), urged the Court to follow
the international community’s lead, these arguments fell
on deaf ears. See McCrudden, A Part of the Main? The
Physician-Assisted Suicide Cases and Comparative Law
Methodology in the United States Supreme Court, in Law at
the End of Life: The Supreme Court and Assisted Suicide
125, 129–130 (C. Schneider ed. 2000).
The Court’s special reliance on the laws of the United
Kingdom is perhaps the most indefensible part of its opinion.
It is of course true that we share a common history with the
United Kingdom, and that we often consult English sources
when asked to discern the meaning of a constitutional text
written against the backdrop of 18th-century English law
and legal thought. If we applied that approach today, our
task would be an easy one. As we explained in Harmelin
v. Michigan, 501 U. S. 957, 973–974 (1991), the “Cruell and
Unusuall Punishments” provision of the English Declaration
of Rights was originally meant to describe those punish-
ments “ ‘out of [the Judges’] Power’ ”—that is, those punish-
ments that were not authorized by common law or statute,
but that were nonetheless administered by the Crown or the
Crown’s judges. Under that reasoning, the death penalty
for under-18 offenders would easily survive this challenge.
The Court has, however—I think wrongly—long rejected a
purely originalist approach to our Eighth Amendment, and
that is certainly not the approach the Court takes today. In-
stead, the Court undertakes the majestic task of determining
(and thereby prescribing) our Nation’s current standards of
decency. It is beyond comprehension why we should look,
for that purpose, to a country that has developed, in the cen-
turies since the Revolutionary War—and with increasing
speed since the United Kingdom’s recent submission to the
jurisprudence of European courts dominated by continental

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jurists—a legal, political, and social culture quite different
from our own. If we took the Court’s directive seriously, we
would also consider relaxing our double jeopardy prohibition,
since the British Law Commission recently published a re-
port that would significantly extend the rights of the prose-
cution to appeal cases where an acquittal was the result of a
judge’s ruling that was legally incorrect. See Law Commis-
sion, Double Jeopardy and Prosecution Appeals, LAW COM
No. 267, Cm 5048, p. 6, ¶ 1.19 (Mar. 2001); J. Spencer, The
English System in European Criminal Procedures 142, 204,
and n. 239 (M. Delmas-Marty & J. Spencer eds. 2002). We
would also curtail our right to jury trial in criminal cases
since, despite the jury system’s deep roots in our shared com-
mon law, England now permits all but the most serious
offenders to be tried by magistrates without a jury. See
D. Feldman, England and Wales, in Criminal Procedure: A
Worldwide Study 91, 114–115 (C. Bradley ed. 1999).
The Court should either profess its willingness to recon-
sider all these matters in light of the views of foreigners, or
else it should cease putting forth foreigners’ views as part of
the reasoned basis of its decisions. To invoke alien law
when it agrees with one’s own thinking, and ignore it other-
wise, is not reasoned decisionmaking, but sophistry.9
9 Justice O’Connor asserts that the Eighth Amendment has a “special
character,” in that it “draws its meaning directly from the maturing values
of civilized society.” Ante, at 604–605. Nothing in the text reflects such
a distinctive character—and we have certainly applied the “maturing val-
ues” rationale to give brave new meaning to other provisions of the Con-
stitution, such as the Due Process Clause and the Equal Protection Clause.
See, e. g., Lawrence v. Texas, 539 U. S. 558, 571–573 (2003); United States
v. Virginia, 518 U. S. 515, 532–534 (1996); Planned Parenthood of South-
eastern Pa. v. Casey, 505 U. S. 833, 847–850 (1992). Justice O’Connor
asserts that an international consensus can at least “serve to confirm the
reasonableness of a consonant and genuine American consensus.” Ante,
at 605. Surely not unless it can also demonstrate the unreasonableness
of such a consensus. Either America’s principles are its own, or they
follow the world; one cannot have it both ways. Finally, Justice O’Con-
nor finds it unnecessary to consult foreign law in the present case because

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The Court responds that “[i]t does not lessen our fidelity
to the Constitution or our pride in its origins to acknowledge
that the express affirmation of certain fundamental rights by
other nations and peoples simply underscores the centrality
of those same rights within our own heritage of freedom.”
Ante, at 578. To begin with, I do not believe that approval
by “other nations and peoples” should buttress our commit-
ment to American principles any more than (what should log-
ically follow) disapproval by “other nations and peoples”
should weaken that commitment. More importantly, how-
ever, the Court’s statement flatly misdescribes what is going
on here. Foreign sources are cited today, not to underscore
our “fidelity” to the Constitution, our “pride in its origins,”
and “our own [American] heritage.” To the contrary, they
are cited to set aside the centuries-old American practice—
a practice still engaged in by a large majority of the relevant
States—of letting a jury of 12 citizens decide whether, in the
particular case, youth should be the basis for withholding the
death penalty. What these foreign sources “affirm,” rather
than repudiate, is the Justices’ own notion of how the world
ought to be, and their diktat that it shall be so henceforth
in America. The Court’s parting attempt to downplay the
significance of its extensive discussion of foreign law is un-
convincing. “Acknowledgment” of foreign approval has no
place in the legal opinion of this Court unless it is part of
the basis for the Court’s judgment—which is surely what it
parades as today.
IV
To add insult to injury, the Court affirms the Missouri Su-
preme Court without even admonishing that court for its
there is “no . . . domestic consensus” to be confirmed. Ibid. But since
she believes that the Justices can announce their own requirements of
“moral proportionality” despite the absence of consensus, why would for-
eign law not be relevant to that judgment? If foreign law is powerful
enough to supplant the judgment of the American people, surely it is pow-
erful enough to change a personal assessment of moral proportionality.

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flagrant disregard of our precedent in Stan ford. Until
today, we have always held that “it is this Court’s preroga-
tive alone to overrule one of its precedents.” State Oil Co.
v. Khan, 522 U. S. 3, 20 (1997). That has been true even
where “ ‘changes in judicial doctrine’ ha[ve] significantly un-
dermined” our prior holding, United States v. Hatter, 532
U. S. 557, 567 (2001) (quoting Hatter v. United States, 64 F. 3d
647, 650 (CA Fed. 1995)), and even where our prior holding
“appears to rest on reasons rejected in some other line of
decisions,” Rodriguez de Quijas v. Shearson/American Ex-
press, Inc., 490 U. S. 477, 484 (1989). Today, however, the
Court silently approves a state-court decision that blatantly
rejected controlling precedent.
One must admit that the Missouri Supreme Court’s action,
and this Court’s indulgent reaction, are, in a way, under-
standable. In a system based upon constitutional and statu-
tory text democratically adopted, the concept of “law” ordi-
narily signifies that particular words have a fixed meaning.
Such law does not change, and this Court’s pronouncement of
it therefore remains authoritative until (confessing our prior
error) we overrule. The Court has purported to make of
the Eighth Amendment, however, a mirror of the passing
and changing sentiment of American society regarding pe-
nology. The lower courts can look into that mirror as well
as we can; and what we saw 15 years ago bears no necessary
relationship to what they see today. Since they are not
looking at the same text, but at a different scene, why should
our earlier decision control their judgment?
However sound philosophically, this is no way to run a
legal system. We must disregard the new reality that, to
the extent our Eighth Amendment decisions constitute
something more than a show of hands on the current Jus-
tices’ current personal views about penology, they purport
to be nothing more than a snapshot of American public opin-
ion at a particular point in time (with the timeframes now
shortened to a mere 15 years). We must treat these deci-

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630 ROPER v. SIMMONS
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sions just as though they represented real law, real prescrip-
tions democratically adopted by the American people, as con-
clusively (rather than sequentially) construed by this Court.
Allowing lower courts to reinterpret the Eighth Amendment
whenever they decide enough time has passed for a new
snapshot leaves this Court’s decisions without any force—
especially since the “evolution” of our Eighth Amendment is
no longer determined by objective criteria. To allow lower
courts to behave as we do, “updating” the Eighth Amend-
ment as needed, destroys stability and makes our case law
an unreliable basis for the designing of laws by citizens and
their representatives, and for action by public officials. The
result will be to crown arbitrariness with chaos.