UNITED STATES v. GRUBBS

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90 OCTOBER TERM, 2005
Syllabus
UNITED STATES v. GRUBBS
certiorari to the united states court of appeals for
the ninth circuit
No. 04–1414. Argued January 18, 2006—Decided March 21, 2006
A Magistrate Judge issued an “anticipatory” search warrant for respond
ent Grubbs’ house based on a federal officer’s affidavit. The affidavit
explained that the warrant would not be executed until a parcel contain
ing a videotape of child pornography—which Grubbs had ordered from
an undercover postal inspector—was received at, and physically taken
into, the residence. The affidavit also referred to two attachments
describing the residence and the items to be seized. After the package
was delivered and the search commenced, Grubbs was given a copy of
the warrant, which included the attachments but not the supporting
affidavit. When he admitted ordering the videotape, he was arrested,
and the videotape and other items were seized. Following his indict
ment for receiving child pornography, see 18 U. S. C. § 2252(a)(2), Grubbs
moved to suppress the seized evidence, arguing, inter alia, that the
warrant was invalid because it failed to list the triggering condition.
The District Court denied the motion, and Grubbs pleaded guilty. The
Ninth Circuit reversed, concluding that the warrant ran afoul of
the Fourth Amendment’s particularity requirement, which, under Cir
cuit precedent, applied to the conditions precedent to an anticipatory
warrant.
Held:
1. Anticipatory warrants are not categorically unconstitutional under
the Fourth Amendment’s provision that “no Warrants shall issue, but
upon probable cause.” Probable cause exists when “there is a fair prob
ability that contraband or evidence of a crime will be found in a par
ticular place.” Illinois v. Gates, 462 U. S. 213, 238. When an anticipa
tory warrant is issued, the fact that the contraband is not presently at
the place described is immaterial, so long as there is probable cause to
believe it will be there when the warrant is executed. Anticipatory
warrants are, therefore, no different in principle from ordinary war
rants: They require the magistrate to determine (1) that it is now proba
ble that (2) contraband, evidence of a crime, or a fugitive will be on
the described premises (3) when the warrant is executed. Where the
anticipatory warrant places a condition (other than the mere passage of
time) upon its execution, the first of these determinations goes not

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Syllabus
merely to what will probably be found if the condition is met, but also
to the likelihood that the condition will be met, and thus that a proper
object of seizure will be on the described premises. Here, the occur
rence of the triggering condition—successful delivery of the videotape—
would plainly establish probable cause for the search, and the affidavit
established probable cause to believe the triggering condition would be
satisfied. Pp. 94–97.
2. The warrant at issue did not violate the Fourth Amendment’s
particularity requirement. The Amendment specifies only two mat
ters that the warrant must “particularly describ[e]”: “the place to be
searched” and “the persons or things to be seized.” That language is
decisive here; the particularity requirement does not include the condi
tions precedent to execution of the warrant. Cf. Dalia v. United States,
441 U. S. 238, 255, 257. Respondent’s two policy rationales—that set
ting forth the triggering condition in the warrant itself is necessary
(1) to delineate the limits of the executing officer’s power and (2) to
allow the individual whose property is searched or seized to police the
officer’s conduct—find no basis in either the Fourth Amendment or Fed
eral Rule of Criminal Procedure 41. Pp. 97–99.
377 F. 3d 1072 and 389 F. 3d 1306, reversed and remanded.
Scalia, J., delivered the opinion of the Court, in which Roberts, C. J.,
and Kennedy, Thomas, and Breyer, JJ., joined, and in which Stevens,
Souter, and Ginsburg, JJ., joined as to Parts I and II. Souter, J., filed
an opinion concurring in part and concurring in the judgment, in which
Stevens and Ginsburg, JJ., joined, post, p. 99. Alito, J., took no part
in the consideration or decision of the case.
Deputy Solicitor General Dreeben argued the cause for
the United States. With him on the briefs were Solicitor
General Clement, Assistant Attorney General Fisher, and
Dan Himmelfarb.
Mark J. Reichel argued the cause for respondent. With
him on the brief were Linda C. Harter and Jeffrey T. Green.*
*Daniel L. Kaplan and Jeffrey L. Fisher filed a brief for the National
Association of Criminal Defense Lawyers et al. as amici curiae urging
affirmance.
Ric Simmons filed a brief for the National Association of Federal De
fenders as amicus curiae.

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92 UNITED STATES v. GRUBBS
Opinion of the Court
Justice Scalia delivered the opinion of the Court.
Federal law enforcement officers obtained a search war
rant for respondent’s house on the basis of an affidavit
explaining that the warrant would be executed only after
a controlled delivery of contraband to that location. We
address two challenges to the constitutionality of this antic
ipatory warrant.
I
Respondent Jeffrey Grubbs purchased a videotape con
taining child pornography from a Web site operated by an
undercover postal inspector. Officers from the Postal In
spection Service arranged a controlled delivery of a package
containing the videotape to Grubbs’ residence. A postal
inspector submitted a search warrant application to a Mag
istrate Judge for the Eastern District of California, accom
panied by an affidavit describing the proposed operation in
detail. The affidavit stated:
“Execution of this search warrant will not occur unless
and until the parcel has been received by a person(s) and
has been physically taken into the residence . . . . At
that time, and not before, this search warrant will be
executed by me and other United States Postal in
spectors, with appropriate assistance from other law en
forcement officers in accordance with this warrant’s
command.” App. to Pet. for Cert. 72a.
In addition to describing this triggering condition, the affi
davit referred to two attachments, which described Grubbs’
residence and the items officers would seize. These attach
ments, but not the body of the affidavit, were incorporated
into the requested warrant. The affidavit concluded:
“Based upon the foregoing facts, I respectfully submit
there exists probable cause to believe that the items set
forth in Attachment B to this affidavit and the search
warrant, will be found [at Grubbs’ residence], which resi
dence is further described at Attachment A.” Ibid.

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Opinion of the Court
The Magistrate Judge issued the warrant as requested.
Two days later, an undercover postal inspector delivered the
package. Grubbs’ wife signed for it and took the unopened
package inside. The inspectors detained Grubbs as he left
his home a few minutes later, then entered the house and
commenced the search. Roughly 30 minutes into the search,
Grubbs was provided with a copy of the warrant, which in
cluded both attachments but not the supporting affidavit that
explained when the warrant would be executed. Grubbs
consented to interrogation by the postal inspectors and ad
mitted ordering the videotape. He was placed under arrest,
and various items were seized, including the videotape.
A grand jury for the Eastern District of California
indicted Grubbs on one count of receiving a visual depiction
of a minor engaged in sexually explicit conduct. See 18
U. S. C. § 2252(a)(2). He moved to suppress the evidence
seized during the search of his residence, arguing as relevant
here that the warrant was invalid because it failed to list
the triggering condition. After an evidentiary hearing, the
District Court denied the motion. Grubbs pleaded guilty,
but reserved his right to appeal the denial of his motion to
suppress.
The Court of Appeals for the Ninth Circuit reversed. 377
F. 3d 1072, amended, 389 F. 3d 1306 (2004). Relying on Cir
cuit precedent, it held that “the particularity requirement of
the Fourth Amendment applies with full force to the condi
tions precedent to an anticipatory search warrant.” 377
F. 3d, at 1077–1078 (citing United States v. Hotal, 143 F. 3d
1223, 1226 (CA9 1998)). An anticipatory warrant defective
for that reason may be “cur[ed]” if the conditions precedent
are set forth in an affidavit that is incorporated in the war
rant and “presented to the person whose property is being
searched.” 377 F. 3d, at 1079. Because the postal inspec
tors “failed to present the affidavit—the only document in
which the triggering conditions were listed”—to Grubbs or

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his wife, the “warrant was . . . inoperative, and the search
was illegal.” Ibid. We granted certiorari. 545 U. S. 1164
(2005).
II
Before turning to the Ninth Circuit’s conclusion that the
warrant at issue here ran afoul of the Fourth Amendment’s
particularity requirement, we address the antecedent ques
tion whether anticipatory search warrants are categorically
unconstitutional.1 An anticipatory warrant is “a warrant
based upon an affidavit showing probable cause that at some
future time (but not presently) certain evidence of crime will
be located at a specified place.” 2 W. LaFave, Search and
Seizure § 3.7(c), p. 398 (4th ed. 2004). Most anticipatory war
rants subject their execution to some condition precedent
other than the mere passage of time—a so-called “triggering
condition.” The affidavit at issue here, for instance, ex
plained that “[e]xecution of th[e] search warrant will not
occur unless and until the parcel [containing child pornogra
phy] has been received by a person(s) and has been physically
taken into the residence.” App. to Pet. for Cert. 72a. If
the government were to execute an anticipatory warrant
before the triggering condition occurred, there would be no
reason to believe the item described in the warrant could be
found at the searched location; by definition, the triggering
condition which establishes probable cause has not yet been
satisfied when the warrant is issued. Grubbs argues that
for this reason anticipatory warrants contravene the Fourth
1 This issue is “predicate to an intelligent resolution of the question pre
sented.” Ohio v. Robinette, 519 U. S. 33, 38 (1996) (internal quotation
marks omitted). It makes little sense to address what the Fourth Amend
ment requires of anticipatory search warrants if it does not allow them
at all. Cf. Wilkinson v. Austin, 545 U. S. 209, 221 (2005) (addressing
whether inmates had a liberty interest in avoiding assignment to a “Super
max” prison, despite the State’s concession that they did, because “[w]e
need reach the question of what process is due only if the inmates establish
a constitutionally protected liberty interest”).

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Amendment’s provision that “no Warrants shall issue, but
upon probable cause.”
We reject this view, as has every Court of Appeals to con
front the issue, see, e. g., United States v. Loy, 191 F. 3d 360,
364 (CA3 1999) (collecting cases). Probable cause exists
when “there is a fair probability that contraband or evidence
of a crime will be found in a particular place.” Illinois v.
Gates, 462 U. S. 213, 238 (1983). Because the probable-cause
requirement looks to whether evidence will be found when
the search is conducted, all warrants are, in a sense, “antici
patory.” In the typical case where the police seek permis
sion to search a house for an item they believe is already
located there, the magistrate’s determination that there is
probable cause for the search amounts to a prediction that
the item will still be there when the warrant is executed.
See People v. Glen, 30 N. Y. 2d 252, 258, 282 N. E. 2d 614,
617 (1972) (“[P]resent possession is only probative of the like
lihood of future possession”).2 The anticipatory nature of
warrants is even clearer in the context of electronic surveil
lance. See, e. g., Katz v. United States, 389 U. S. 347 (1967).
When police request approval to tap a telephone line, they
do so based on the probability that, during the course of the
surveillance, the subject will use the phone to engage in
crime-related conversations. The relevant federal provision
requires a judge authorizing “interception of wire, oral, or
electronic communications” to determine that “there is prob
2 For this reason, probable cause may cease to exist after a warrant is
issued. The police may learn, for instance, that contraband is no longer
located at the place to be searched. See, e. g., United States v. Bowling,
900 F. 2d 926, 932 (CA6 1990) (recognizing that a fruitless consent search
could “dissipat[e] the probable cause that justified a warrant”). Or the
probable-cause showing may have grown “stale” in view of the time that
has passed since the warrant was issued. See United States v. Wagner,
989 F. 2d 69, 75 (CA2 1993) (“[T]he facts in an affidavit supporting a search
warrant must be sufficiently close in time to the issuance of the warrant
and the subsequent search conducted so that probable cause can be said
to exist as of the time of the search and not simply as of some time in the
past”); see also Sgro v. United States, 287 U. S. 206, 210–211 (1932).

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able cause for belief that particular communications con
cerning [one of various listed offenses] will be obtained
through such interception.” 18 U. S. C. § 2518(3)(b) (empha
sis added); see also United States v. Ricciardelli, 998 F. 2d
8, 11, n. 3 (CA1 1993) (“[T]he magistrate issues the warrant
on the basis of a substantial probability that crime-related
conversations will ensue”). Thus, when an anticipatory war
rant is issued, “the fact that the contraband is not presently
located at the place described in the warrant is immaterial,
so long as there is probable cause to believe that it will be
there when the search warrant is executed.” United States
v. Garcia, 882 F. 2d 699, 702 (CA2 1989) (quoting United
States v. Lowe, 575 F. 2d 1193, 1194 (CA6 1978); internal quo
tation marks omitted).
Anticipatory warrants are, therefore, no different in prin
ciple from ordinary warrants. They require the magistrate
to determine (1) that it is now probable that (2) contraband,
evidence of a crime, or a fugitive will be on the described
premises (3) when the warrant is executed. It should be
noted, however, that where the anticipatory warrant places
a condition (other than the mere passage of time) upon its
execution, the first of these determinations goes not merely
to what will probably be found if the condition is met. (If
that were the extent of the probability determination, an an
ticipatory warrant could be issued for every house in the
country, authorizing search and seizure if contraband should
be delivered—though for any single location there is no like
lihood that contraband will be delivered.) Rather, the prob
ability determination for a conditioned anticipatory warrant
looks also to the likelihood that the condition will occur, and
thus that a proper object of seizure will be on the described
premises. In other words, for a conditioned anticipatory
warrant to comply with the Fourth Amendment’s require
ment of probable cause, two prerequisites of probability must
be satisfied. It must be true not only that if the triggering
condition occurs “there is a fair probability that contraband
or evidence of a crime will be found in a particular place,”

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Gates, supra, at 238, but also that there is probable cause
to believe the triggering condition will occur. The support
ing affidavit must provide the magistrate with sufficient
information to evaluate both aspects of the probable-cause
determination. See Garcia, supra, at 703.
In this case, the occurrence of the triggering condition—
successful delivery of the videotape to Grubbs’ residence—
would plainly establish probable cause for the search. In
addition, the affidavit established probable cause to believe
the triggering condition would be satisfied. Although it is
possible that Grubbs could have refused delivery of the vid
eotape he had ordered, that was unlikely. The Magistrate
therefore “had a ‘substantial basis for . . . conclud[ing]’ that
probable cause existed.” Gates, supra, at 238–239 (quoting
Jones v. United States, 362 U. S. 257, 271 (1960)).
III
The Ninth Circuit invalidated the anticipatory search war
rant at issue here because the warrant failed to specify the
triggering condition. The Fourth Amendment’s particular
ity requirement, it held, “applies with full force to the con
ditions precedent to an anticipatory search warrant.” 377
F. 3d, at 1077–1078.
The Fourth Amendment, however, does not set forth some
general “particularity requirement.” It specifies only two
matters that must be “particularly describ[ed]” in the war
rant: “the place to be searched” and “the persons or things
to be seized.” We have previously rejected efforts to ex
pand the scope of this provision to embrace unenumerated
matters. In Dalia v. United States, 441 U. S. 238 (1979), we
considered an order authorizing the interception of oral com
munications by means of a “bug” installed by the police in
the petitioner’s office. The petitioner argued that, if a co
vert entry is necessary to install such a listening device, the
authorizing order must “explicitly set forth its approval of
such entries before the fact.” Id., at 255. This argument
fell before the “ ‘precise and clear’ ” words of the Fourth

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Amendment: “Nothing in the language of the Constitution or
in this Court’s decisions interpreting that language suggests
that, in addition to the [requirements set forth in the text],
search warrants also must include a specification of the pre
cise manner in which they are to be executed.” Ibid. (quot
ing Stanford v. Texas, 379 U. S. 476, 481 (1965)); 441 U. S., at
257. The language of the Fourth Amendment is likewise
decisive here; its particularity requirement does not include
the conditions precedent to execution of the warrant.
Respondent, drawing upon the Ninth Circuit’s analysis
below, relies primarily on two related policy rationales.
First, he argues, setting forth the triggering condition in the
warrant itself is necessary “to delineate the limits of the exe
cuting officer’s power.” Brief for Respondent 20. This is
an application, respondent asserts, of the following principle:
“[I]f there is a precondition to the valid exercise of executive
power, that precondition must be particularly identified on
the face of the warrant.” Id., at 23. That principle is not
to be found in the Constitution. The Fourth Amendment
does not require that the warrant set forth the magistrate’s
basis for finding probable cause, even though probable cause
is the quintessential “precondition to the valid exercise of
executive power.” Much less does it require description of
a triggering condition.
Second, respondent argues that listing the triggering
condition in the warrant is necessary to “ ‘assur[e] the indi
vidual whose property is searched or seized of the lawful
authority of the executing officer, his need to search, and the
limits of his power to search.’ ” Id., at 19 (quoting United
States v. Chadwick, 433 U. S. 1, 9 (1977)). The Ninth Circuit
went even further, asserting that if the property owner were
not informed of the triggering condition, he “would ‘stand
[no] real chance of policing the officers’ conduct.’ ” 377 F. 3d,
at 1079 (quoting Ramirez v. Butte-Silver Bow County, 298
F. 3d 1022, 1027 (CA9 2002)). This argument assumes that
the executing officer must present the property owner with

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Opinion of Souter, J.
a copy of the warrant before conducting his search. See 377
F. 3d, at 1079, n. 9. In fact, however, neither the Fourth
Amendment nor Federal Rule of Criminal Procedure 41 im
poses such a requirement. See Groh v. Ramirez, 540 U. S.
551, 562, n. 5 (2004). “The absence of a constitutional re
quirement that the warrant be exhibited at the outset of the
search, or indeed until the search has ended, is . . . evidence
that the requirement of particular description does not pro
tect an interest in monitoring searches.” United States v.
Stefonek, 179 F. 3d 1030, 1034 (CA7 1999) (citations omitted).
The Constitution protects property owners not by giving
them license to engage the police in a debate over the basis
for the warrant, but by interposing, ex ante, the “deliberate,
impartial judgment of a judicial officer . . . between the
citizen and the police,” Wong Sun v. United States, 371 U. S.
471, 481–482 (1963), and by providing, ex post, a right to sup
press evidence improperly obtained and a cause of action
for damages.
* * *
Because the Fourth Amendment does not require that the
triggering condition for an anticipatory search warrant be
set forth in the warrant itself, the Court of Appeals erred in
invalidating the warrant at issue here. The judgment of the
Court of Appeals is reversed, and the case is remanded for
further proceedings consistent with this opinion.
It is so ordered.
Justice Alito took no part in the consideration or deci
sion of this case.
Justice Souter, with whom Justice Stevens and Jus
tice Ginsburg join, concurring in part and concurring in
the judgment.
I agree with the Court that anticipatory warrants are con
stitutional for the reasons stated in Part II of the Court’s

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opinion, and I join in the disposition of this case. But I
would qualify some points made in Part III.
The Court notes that a warrant’s failure to specify the
place to be searched and the objects sought violates an
express textual requirement of the Fourth Amendment,
whereas the text says nothing about a condition placed by
the issuing magistrate on the authorization to search (here,
delivery of the package of contraband). That textual differ
ence is, however, no authority for neglecting to specify the
point or contingency intended by the magistrate to trigger
authorization, and the government should beware of banking
on the terms of a warrant without such specification. The
notation of a starting date was an established feature even of
the objectionable 18th-century writs of assistance, see, e. g.,
Massachusetts Writs of Assistance Bill, 1762, reprinted in
M. Smith, The Writs of Assistance Case 567–568 (1978); Writ
of Assistance (English) of George III, 1761, reprinted in id.,
at 524–527. And it is fair to say that the very word “war
rant” in the Fourth Amendment means a statement of au
thority that sets out the time at which (or, in the case of
anticipatory warrants, the condition on which) the authoriza
tion begins.*
An issuing magistrate’s failure to mention that condition
can lead to several untoward consequences with constitu
tional significance. To begin with, a warrant that fails to
tell the truth about what a magistrate authorized cannot in
form the police officer’s responsibility to respect the limits
of authorization, see Groh v. Ramirez, 540 U. S. 551, 560–563,
and n. 4 (2004), a failing assuming real significance when the
warrant is not executed by the official who applied for it and
happens to know the unstated condition. The peril is that
if an officer simply takes such a warrant on its face and
makes the ostensibly authorized search before the unstated
*Federal Rule of Criminal Procedure 41(e)(2)(A) in fact requires that an
issued warrant command the executing officer to “execute the warrant
within a specified time no longer than 10 days.”

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condition has been met, the search will be held unreasonable.
It is true that we have declined to apply the exclusionary
rule when a police officer reasonably relies on the product of
a magistrate’s faulty judgment or sloppy practice, see Mas
sachusetts v. Sheppard, 468 U. S. 981, 987–991 (1984). But
when a government officer obtains what the magistrate says
is an anticipatory warrant, he must know or should realize
when it omits the condition on which authorization depends,
and it is hard to see why the government should not be held
to the condition despite the unconditional face of the war
rant. Cf. Groh v. Ramirez, supra, at 554–555, 563, and n. 6
(declaring unconstitutional a search conducted pursuant to a
warrant failing to specify the items the government asked
the magistrate permission to seize in part because “officers
leading a search team must ‘make sure that they have a
proper warrant that in fact authorizes the search and seizure
they are about to conduct’ ” (brackets omitted)).
Nor does an incomplete anticipatory warrant address an
owner’s interest in an accurate statement of the govern
ment’s authority to search property. To be sure, the extent
of that interest is yet to be settled; in Groh v. Ramirez,
supra, the Court was careful to note that the right of an
owner to demand to see a copy of the warrant before making
way for the police had not been determined, id., at 562, n. 5,
and it remains undetermined today. But regardless of any
right on the owner’s part, showing an accurate warrant reli
ably “assures the individual whose property is searched or
seized of the lawful authority of the executing officer, his
need to search, and the limits of his power to search.”
United States v. Chadwick, 433 U. S. 1, 9 (1977), quoted in
Groh v. Ramirez, supra, at 561. And if a later case holds
that the homeowner has a right to inspect the warrant on
request, a statement of the condition of authorization would
give the owner a right to correct any misapprehension on
the police’s part that the condition had been met when in
fact it had not been. If the police were then to enter any

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way without a reasonable (albeit incorrect) justification, the
search would certainly be open to serious challenge as unrea
sonable within the meaning of the Fourth Amendment.