BANKS v. DRETKE, DIRECTOR, TEXAS DEPART- MENT OF CRIMINAL JUSTICE, CORRECTIONAL INSTITUTIONS DIVISION

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668 OCTOBER TERM, 2003
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BANKS v. DRETKE, DIRECTOR, TEXAS DEPART-
MENT OF CRIMINAL JUSTICE, CORRECTIONAL
INSTITUTIONS DIVISION
certiorari to the united states court of appeals for
the fifth circuit
No. 02–8286. Argued December 8, 2003—Decided February 24, 2004
After police found a gun-shot corpse near Texarkana, Texas, Deputy Sher-
iff Willie Huff learned that the decedent had been seen with petitioner
Banks three days earlier. When a paid informant told Deputy Huff that
Banks was driving to Dallas to fetch a weapon, Deputy Huff followed
Banks to a residence there. On the return trip, police stopped Banks’s
vehicle, found a handgun, and arrested the car’s occupants. Returning
to the Dallas residence, Deputy Huff encountered Charles Cook and re-
covered a second gun, which Cook said Banks had left at the residence
several days earlier. On testing, the second gun proved to be the
murder weapon. Prior to Banks’s trial, the State advised defense coun-
sel that, without necessity of motions, the State would provide Banks
with all discovery to which he was entitled. Nevertheless, the State
withheld evidence that would have allowed Banks to discredit two es-
sential prosecution witnesses. At the trial’s guilt phase, Cook testified,
inter alia, that Banks admitted “kill[ing a] white boy.” On cross-
examination, Cook thrice denied talking to anyone about his testimony.
In fact, Deputy Huff and prosecutors intensively coached Cook about his
testimony during at least one pretrial session. The prosecution allowed
Cook’s misstatements to stand uncorrected. After Banks’s capital
murder conviction, the penalty-phase jury found that Banks would prob-
ably commit criminal acts of violence that would constitute a continuing
threat to society. One of the State’s two penalty-phase witnesses, Rob-
ert Farr, testified that Banks had retrieved a gun from Dallas in order
to commit robberies. According to Farr, Banks had said he would “take
care of it” if trouble arose during those crimes. Two defense witnesses
impeached Farr, but were, in turn, impeached. Banks testified, among
other things, that, although he had traveled to Dallas to obtain a gun,
he had no intent to participate in the robberies, which Farr alone
planned to commit. In summation, the prosecution suggested that
Banks had not traveled to Dallas only to supply Farr with a weapon.
Stressing Farr’s testimony that Banks said he would “take care” of
trouble arising during the robberies, the prosecution urged the jury to
find Farr credible. Farr’s admission that he used narcotics, the prose-

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669 Cite as: 540 U. S. 668 (2004)
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cution suggested, indicated that he had been open and honest in every
way. The State did not disclose that Farr was the paid informant who
told Deputy Huff about the Dallas trip. The judge sentenced Banks
to death.
Through Banks’s direct appeal, the State continued to hold secret
Farr’s and Cook’s links to the police. In a 1992 state-court postconvic-
tion motion, Banks alleged for the first time that the prosecution know-
ingly failed to turn over exculpatory evidence that would have revealed
Farr as a police informant and Banks’s arrest as a “set-up.” Banks also
alleged that during the trial’s guilt phase, the State deliberately with-
held information of a deal prosecutors made with Cook, which would
have been critical to the jury’s assessment of Cook’s credibility. Banks
asserted that the State’s actions violated Brady v. Maryland, 373 U. S.
83, 87, which held that the prosecution’s suppression of evidence re-
quested by and favorable to an accused violates due process where the
evidence is material to either guilt or punishment, irrespective of the
prosecution’s good or bad faith. The State denied Banks’s allegations,
and the state postconviction court rejected his claims.
In 1996, Banks filed the instant federal habeas petition, alleging, as
relevant, that the State had withheld material exculpatory evidence re-
vealing Farr to be a police informant and Banks’ arrest as a “set-up.”
Banks further alleged that the State had concealed Cook’s incentive to
testify in a manner favorable to the prosecution. Banks attached affi-
davits from Farr and Cook to a February 1999 motion seeking discovery
and an evidentiary hearing. Farr’s declaration stated that he had
agreed to help Deputy Huff with the murder investigation out of fear
Huff would arrest him on drug charges; that Huff had paid him $200;
and that Farr had “set [Banks] up” by convincing him to drive to Dallas
to retrieve Banks’s gun. Cook recalled that he had participated in prac-
tice sessions before the Banks trial at which prosecutors told him he
must either testify as they wanted or spend the rest of his life in prison.
In response to the Magistrate Judge’s disclosure order in the federal
habeas proceeding, the prosecution gave Banks a transcript of a Septem-
ber 1980 pretrial interrogation of Cook by police and prosecutors. This
transcript provided compelling evidence that Cook’s testimony had been
tutored, but did not bear on whether Cook had a deal with the prosecu-
tion. At the federal evidentiary hearing Huff acknowledged, for the
first time, that Farr was an informant paid for his involvement in
Banks’s case. A Banks trial prosecutor testified, however, that no deal
had been offered to gain Cook’s testimony. The Magistrate Judge rec-
ommended a writ of habeas corpus with respect to Banks’s death sen-
tence based on, inter alia, the State’s failure to disclose Farr’s informant
status. The judge did not recommend disturbing the guilt-phase ver-

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670 BANKS v. DRETKE
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dict, concluding in this regard that Banks had not properly pleaded a
Brady claim based on the September 1980 Cook interrogation tran-
script. The District Court adopted the Magistrate Judge’s report and
rejected Banks’s argument that the Cook transcript claim be treated as
if raised in the pleadings, under Federal Rule of Civil Procedure 15(b).
The Fifth Circuit reversed to the extent the District Court had
granted relief on Banks’s Farr Brady claim. The Court of Appeals rec-
ognized that, prior to federal habeas proceedings, the prosecution had
suppressed Farr’s informant status and his part in the Dallas trip. The
Fifth Circuit nonetheless concluded that Banks did not act diligently to
develop the facts underpinning his Farr Brady claim when he pursued
his 1992 state-court postconviction application. That lack of diligence,
the Court of Appeals held, rendered the evidence uncovered in the fed-
eral habeas proceeding procedurally barred. In any event, the Fifth
Circuit ruled, Farr’s status as an informant was not “material” for
Brady purposes. That was so, in the Fifth Circuit’s judgment, because
Banks had impeached Farr at trial by bringing out that he had been an
unreliable police informant in Arkansas, and because much of Farr’s
testimony was corroborated by other witnesses, including Banks him-
self, who had acknowledged his willingness to get a gun for Farr’s use
in robberies. The Fifth Circuit also denied a certificate of appealability
on Banks’s Cook Brady claim. In accord with the District Court, the
Court of Appeals rejected Banks’s assertion that, because his Cook
Brady claim had been aired by implied consent, Rule 15(b) required it
to be treated as if raised in the pleadings.
Held: The Fifth Circuit erred in dismissing Banks’s Farr Brady claim and
denying him a certificate of appealability on his Cook Brady claim.
When police or prosecutors conceal significant exculpatory or impeach-
ing material in the State’s possession, it is ordinarily incumbent on the
State to set the record straight. Pp. 689–706.
(a) Both of Banks’s Brady claims arose under the regime in place
prior to the Antiterrorism and Effective Death Penalty Act of 1996
(AEDPA). P. 689.
(b) Banks’s Farr Brady claim, as it trains on his death sentence, is
not barred. All three elements of a Brady claim are satisfied as to the
suppression of Farr’s informant status and its bearing on the reliability
of the jury’s verdict regarding punishment. Because Banks has also
demonstrated cause and prejudice, he is not precluded from gaining fed-
eral habeas relief by his failure to produce evidence in anterior state-
court proceedings. Pp. 690–703.
(1) Pre-AEDPA habeas law required Banks to exhaust available
state-court remedies in order to pursue federal-court relief. See, e. g.,

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Rose v. Lundy, 455 U. S. 509. Banks satisfied this requirement by alleg-
ing in his 1992 state-court habeas application that the prosecution know-
ingly failed to turn over exculpatory evidence about Farr. Banks,
however, failed to produce evidence in state postconviction court estab-
lishing that Farr had served as Deputy Sheriff Huff ’s informant. In
the federal habeas forum, Banks must show that he was not thereby
barred from producing evidence to substantiate his Farr Brady claim.
Banks would be entitled to a federal-court evidentiary hearing if he
could show both cause for his failure to develop facts in state court, and
actual prejudice resulting from that failure. Keeney v. Tamayo-Reyes,
504 U. S. 1, 11. A Brady prosecutorial misconduct claim has three es-
sential elements. Strickler v. Greene, 527 U. S. 263, 281–282. Beyond
debate, the first such element—that the evidence at issue be favorable
to the accused as exculpatory or impeaching—is satisfied here. Farr’s
paid informant status plainly qualifies as evidence advantageous to
Banks. Cause and prejudice in this case parallel the second and third
of the three Brady components. Corresponding to the second Brady
element—that the State suppressed the evidence at issue—a petitioner
shows cause when the reason for the failure to develop facts in state-
court proceedings was the State’s suppression of the relevant evidence.
Coincident with the third Brady component—that prejudice ensued—
prejudice within the compass of the “cause and prejudice” requirement
exists when suppressed evidence is “material” for Brady purposes.
Ibid. Thus, if Banks succeeds in demonstrating cause and prejudice,
he will also succeed in establishing the essential elements of his Farr
Brady claim. Pp. 690–691.
(2) Banks has shown cause for failing to present evidence in state
court capable of substantiating his Farr Brady claim. As Strickler
instructs, 527 U. S., at 289, three inquiries underlie the “cause” deter-
mination: (1) whether the prosecution withheld exculpatory evidence;
(2) whether the petitioner reasonably relied on the prosecution’s open
file policy as fulfilling the prosecution’s duty to disclose such evidence;
and (3) whether the State confirmed the petitioner’s reliance on that
policy by asserting during the state habeas proceedings that the peti-
tioner had already received everything known to the government. This
case is congruent with Strickler in all three respects. First, the State
knew of, but kept back, Farr’s arrangement with Deputy Huff. Cf.
Kyles v. Whitley, 514 U. S. 419, 437. Second, the State asserted, on
the eve of trial, that it would disclose all Brady material. Banks cannot
be faulted for relying on that representation. See Strickler, 527 U. S.,
at 283–284. Third, in its answer to Banks’s 1992 state habeas appli-
cation, the State denied Banks’s assertions that Farr was a police in-
formant and Banks’s arrest a “set-up.” The State thereby confirmed

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672 BANKS v. DRETKE
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Banks’s reliance on the prosecution’s representation that it had disclosed
all Brady material. In this regard, Banks’s case is stronger than was
the Strickler petitioner’s: Each time Farr misrepresented his dealings
with police, the prosecution allowed that testimony to stand uncor-
rected. Cf. Giglio v. United States, 405 U. S. 150, 153. Banks appro-
priately assumed police would not engage in improper litigation conduct
to obtain a conviction. None of the State’s arguments for distinguish-
ing Strickler on the “cause” issue accounts adequately for the State’s
concealment and misrepresentation of Farr’s link to Huff. In light of
those misrepresentations, Banks did not lack appropriate diligence in
pursuing the Farr Brady claim in state court. Nor is Banks at fault for
failing to move, in the 1992 state-court postconviction proceedings, for
investigative assistance so that he could inquire into Farr’s police con-
nections, for state law entitled him to no such aid. Further, Roviaro
v. United States, 353 U. S. 53, which concerned the Government’s obliga-
tion to reveal the identity of an informant it does not call as a witness,
does not support the State’s position. Pp. 692–698.
(3) The State’s suppression of Farr’s informant status is “material”
for Brady purposes. The materiality standard for Brady claims is met
when “the favorable evidence could reasonably be taken to put the
whole case in such a different light as to undermine confidence in the
verdict.” Kyles, 514 U. S., at 435. Farr was paid for a critical role in
the scenario that led to Banks’s indictment. Farr’s declaration, pre-
sented to the federal habeas court, asserts that Farr, not Banks, initi-
ated the proposal to obtain a gun to facilitate robberies. Had Farr not
instigated, upon Deputy Huff ’s request, the Dallas excursion to fetch
Banks’s gun, the prosecution would have had slim, if any, evidence that
Banks planned to continue committing violent acts. Farr’s admission
of his instigating role, moreover, would have dampened the prosecution’s
zeal in urging the jury to consider Banks’s acquisition of a gun to commit
robbery or his “planned violence.” Because Banks had no criminal rec-
ord, Farr’s testimony about Banks’s propensity to violence was crucial
to the prosecution. Without that testimony, the State could not have
underscored to the jury that Banks would use the gun fetched in Dallas
to “take care” of trouble arising during robberies. The stress placed
by the prosecution on this part of Farr’s testimony, uncorroborated by
any other witness, belies the State’s suggestion that Farr’s testimony
was adequately corroborated. The prosecution’s penalty-phase summa-
tion, moreover, left no doubt about the importance the State attached
to Farr’s testimony. In contrast to Strickler, where the Court found
“cause,” 527 U. S., at 289, but no “prejudice,” id., at 292–296, the exist-
ence of “prejudice” in this case is marked. Farr’s trial testimony was
the centerpiece of the Banks prosecution’s penalty-phase case. That

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testimony was cast in large doubt by the declaration Banks ultimately
obtained from Farr and introduced in the federal habeas proceeding.
Had jurors known of Farr’s continuing interest in obtaining Deputy
Huff ’s favor and his receipt of funds to set Banks up, they might well
have distrusted Farr’s testimony, and, insofar as it was uncorroborated,
disregarded it. The jury, moreover, did not benefit from customary,
truth-promoting precautions that generally accompany informant tes-
timony. Such testimony poses serious credibility questions. This
Court, therefore, has long allowed defendants broad latitude to cross-
examine informants and has counseled the use of careful instructions on
submission of the credibility issue to the jury. See, e. g., On Lee v.
United States, 343 U. S. 747, 757. The State’s argument that Farr’s
informant status was rendered cumulative by his impeachment at trial
is contradicted by the record. Neither witness called to impeach Farr
gave evidence directly relevant to Farr’s part in Banks’s prosecution.
The impeaching witnesses, moreover, were themselves impeached, as
the prosecution stressed on summation. Further, the prosecution
turned to its advantage remaining impeachment evidence by suggesting
that Farr’s admission of drug use demonstrated his openness and hon-
esty. Pp. 698–703.
(c) The lower courts wrongly denied Banks a certificate of appealabil-
ity with regard to his Brady claim resting on the prosecution’s suppres-
sion of the September 1980 Cook interrogation transcript. The Court
of Appeals rejected Banks’s contention that Rule 15(b) required the
claim to be treated as having been raised in the pleadings because the
transcript substantiating the claim had been aired at an evidentiary
hearing before the Magistrate Judge. The Fifth Circuit apparently re-
lied on the debatable view that Rule 15(b) is inapplicable in habeas pro-
ceedings. This Court has twice assumed that Rule’s application in such
proceedings. Harris v. Nelson, 394 U. S. 286, 294, n. 5; Withrow v. Wil-
liams, 507 U. S. 680, 696, and n. 7. The Withrow District Court had
granted habeas on a claim neither pleaded, considered at “an evidentiary
hearing,” nor “even argu[ed]” by the parties. Id., at 695. This Court
held that there had been no trial of the claim by implied consent; and
manifestly, the respondent warden was prejudiced by the lack of oppor-
tunity to present evidence bearing on the claim’s resolution. Id., at
696. Here, in contrast, the issue of the undisclosed Cook interrogation
transcript was aired at a hearing before the Magistrate Judge, and the
transcript was admitted into evidence without objection. The Fifth
Circuit’s view that an evidentiary hearing should not be aligned with a
trial for Rule 15(b) purposes is not well grounded. Nor does this Court
agree with the Court of Appeals that applying Rule 15(b) in habeas
proceedings would undermine the State’s exhaustion and procedural de-

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fault defenses. Ibid. Under pre-AEDPA law, no inconsistency arose
between Rule 15(b) and those defenses. Doubtless, that is why this
Court’s pre-AEDPA cases assumed Rule 15(b)’s application in habeas
proceedings. See, e. g., ibid. While AEDPA forbids a finding that ex-
haustion has been waived absent an express waiver by the State, 28
U. S. C. § 2254(b)(3), pre-AEDPA law allowed waiver of both defenses—
exhaustion and procedural default—based on the State’s litigation con-
duct, see, e. g., Gray v. Netherland, 518 U. S. 152, 166. To obtain a cer-
tificate of appealability, a prisoner must demonstrate that reasonable
jurists could disagree with the district court’s resolution of his constitu-
tional claims or that the issues presented warrant encouragement to
proceed further. Miller-El v. Cockrell, 537 U. S. 322, 327. This case
fits that description as to the application of Rule 15(b). Pp. 703–706.
48 Fed. Appx. 104, reversed and remanded.
Ginsburg, J., delivered the opinion of the Court, in which Rehnquist,
C. J., and Stevens, O’Connor, Kennedy, Souter, and Breyer, JJ.,
joined, and in which Scalia and Thomas, JJ., joined as to Part III.
Thomas, J., filed an opinion concurring in part and dissenting in part, in
which Scalia, J., joined, post, p. 706.
George H. Kendall argued the cause for petitioner. With
him on the briefs were Elaine R. Jones, Janai S. Nelson,
Miriam Gohara, and Clifton L. Holmes.
Gena Bunn, Assistant Attorney General of Texas, argued
the cause for respondent. With her on the brief were Greg
Abbott, Attorney General, Barry R. McBee, First Assistant
Attorney General, Jay Kimbrough, Deputy Attorney Gen-
eral, and Edward L. Marshall and Katherine D. Hayes, As-
sistant Attorneys General.*
Justice Ginsburg delivered the opinion of the Court.
Petitioner Delma Banks, Jr., was convicted of capital mur-
der and sentenced to death. Prior to trial, the State advised
*Briefs of amici curiae urging reversal were filed for William G. Broad-
dus et al. by William F. Sheehan; and for John J. Gibbons et al. by Peter
Buscemi and Brooke Clagett.
A. P. Carlton, Jr., Lynn R. Coleman, and Matthew W. S. Estes filed a
brief for the American Bar Association as amicus curiae.

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Banks’s attorney there would be no need to litigate discovery
issues, representing: “[W]e will, without the necessity of
motions[,] provide you with all discovery to which you are
entitled.” App. 361, n. 1; App. to Pet. for Cert. A4 (both
sources’ internal quotation marks omitted). Despite that
undertaking, the State withheld evidence that would have
allowed Banks to discredit two essential prosecution wit-
nesses. The State did not disclose that one of those wit-
nesses was a paid police informant, nor did it disclose a
pretrial transcript revealing that the other witness’ trial tes-
timony had been intensively coached by prosecutors and law
enforcement officers.
Furthermore, the prosecution raised no red flag when the
informant testified, untruthfully, that he never gave the po-
lice any statement and, indeed, had not talked to any police
officer about the case until a few days before the trial. In-
stead of correcting the informant’s false statements, the
prosecutor told the jury that the witness “ha[d] been open
and honest with you in every way,” App. 140, and that his
testimony was of the “utmost significance,” id., at 146. Sim-
ilarly, the prosecution allowed the other key witness to
convey, untruthfully, that his testimony was entirely unre-
hearsed. Through direct appeal and state collateral review
proceedings, the State continued to hold secret the key wit-
nesses’ links to the police and allowed their false statements
to stand uncorrected.
Ultimately, through discovery and an evidentiary hearing
authorized in a federal habeas corpus proceeding, the long-
suppressed evidence came to light. The District Court
granted Banks relief from the death penalty, but the Court
of Appeals reversed. In the latter court’s judgment, Banks
had documented his claims of prosecutorial misconduct too
late and in the wrong forum; therefore he did not qualify
for federal-court relief. We reverse that judgment. When
police or prosecutors conceal significant exculpatory or im-

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peaching material in the State’s possession, it is ordinarily
incumbent on the State to set the record straight.
I
On April 14, 1980, police found the corpse of 16-year-old
Richard Whitehead in Pocket Park, east of Nash, Texas, a
town in the vicinity of Texarkana. Id., at 8, 141.1 A prelim-
inary autopsy revealed that Whitehead had been shot three
times. Id., at 10. Bowie County Deputy Sheriff Willie
Huff, lead investigator of the death, learned from two wit-
nesses that Whitehead had been in the company of peti-
tioner, 21-year-old Delma Banks, Jr., late on the evening of
April 11. Id., at 11–15, 144; Banks v. State, 643 S. W. 2d 129,
131 (Tex. Crim. App. 1982) (en banc), cert. denied, 464 U. S.
904 (1983). On April 23, Huff received a call from a con-
fidential informant reporting that “Banks was coming to Dal-
las to meet an individual and get a weapon.” App. 15.
That evening, Huff and other officers followed Banks to
South Dallas, where Banks visited a residence. Ibid.; Brief
for Petitioner 3. Police stopped Banks’s vehicle en route
from Dallas, found a handgun in the car, and arrested the
car’s occupants. App. 16. Returning to the Dallas resi-
dence Banks had visited, Huff encountered and interviewed
Charles Cook and recovered a second gun, a weapon Cook
said Banks had left with him several days earlier. Ibid.
Tests later identified the second gun as the Whitehead mur-
der weapon. Id., at 17.
In a May 21, 1980, pretrial hearing, Banks’s counsel sought
information from Huff concerning the confidential informant
who told Huff that Banks would be driving to Dallas. Id.,
at 21. Huff was unresponsive. Ibid. Any information
that might reveal the identity of the informant, the prosecu-
1 Although a police officer testified Whitehead’s body was found on April
14, App. 8, the Texas Court of Criminal Appeals stated the body was
discovered on April 15. Banks v. State, 643 S. W. 2d 129, 131 (1982) (en
banc).

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tion urged, was privileged. Id., at 23. The trial court sus-
tained the State’s objection. Id., at 24. Several weeks
later, in a July 7, 1980, letter, the prosecution advised
Banks’s counsel that “[the State] will, without necessity of
motions provide you with all discovery to which you are enti-
tled.” Id., at 361, n. 1; App. to Pet. for Cert. A4 (both
sources’ internal quotation marks omitted).
The guilt phase of Banks’s trial spanned two days in Sep-
tember 1980. See Brief for Petitioner 2; App. to Pet. for
Cert. C3. Witnesses testified to seeing Banks and White-
head together on April 11 in Whitehead’s green Mustang,
and to hearing gunshots in Pocket Park at 4 a.m. on April
12. Banks v. State, 643 S. W. 2d, at 131. Charles Cook tes-
tified that Banks arrived in Dallas in a green Mustang at
about 8:15 a.m. on April 12, and stayed with Cook until April
14. App. 42–43, 47–53. Cook gave the following account of
Banks’s visit. On the morning of his arrival, Banks had
blood on his leg and told Cook “he [had] got into it on the
highway with a white boy.” Id., at 44. That night, Banks
confessed to having “kill[ed] the white boy for the hell of it
and take[n] his car and come to Dallas.” Id., at 48. During
their ensuing conversation, Cook first noticed that “[Banks]
had a pistol.” Id., at 49. Two days later, Banks left Dallas
by bus. Id., at 52–53. The next day, Cook abandoned the
Mustang in West Dallas and sold Banks’s gun to a neighbor.
Id., at 54. Cook further testified that, shortly before the
police arrived at his residence to question him, Banks had
revisited him and requested the gun. Id., at 57.
On cross-examination, Cook three times represented that
he had not talked to anyone about his testimony. Id., at 59.
In fact, however, Cook had at least one “pretrial practice
sessio[n]” at which Huff and prosecutors intensively coached
Cook for his appearance on the stand at Banks’s trial. Id.,
at 325, ¶ 10, 381–390; Joint Lodging Material 1–36 (transcript
of pretrial preparatory session). The prosecution allowed
Cook’s misstatements to stand uncorrected. In its guilt-

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phase summation, the prosecution told the jury “Cook
brought you absolute truth.” App. 84.
In addition to Cook, Robert Farr was a key witness for
the prosecution. Corroborating parts of Cook’s account,
Farr testified to traveling to Dallas with Banks to retrieve
Banks’s gun. Id., at 34–35. On cross-examination, defense
counsel asked Farr whether he had “ever taken any money
from some police officers,” or “give[n] any police officers a
statement.” Id., at 37–38. Farr answered no to both ques-
tions; he asserted emphatically that police officers had not
promised him anything and that he had “talked to no one
about this [case]” until a few days before trial. Ibid. These
answers were untrue, but the State did not correct them.
Farr was the paid informant who told Deputy Sheriff Huff
that Banks would travel to Dallas in search of a gun. Id.,
at 329; App. to Pet. for Cert. A4, A9. In a 1999 affidavit,
Farr explained:
“I assumed that if I did not help [Huff] with his investi-
gation of Delma that he would have me arrested for drug
charges. That’s why I agreed to help [Huff]. I was
afraid that if I didn’t help him, I would be arrested. . . .
“Willie Huff asked me to help him find Delma’s gun.
I told [Huff] that he would have to pay me money right
away for my help on the case. I think altogether he
gave me about $200.00 for helping him. He paid me
some of the money before I set Delma up. He paid me
the rest after Delma was arrested and charged with
murder. . . .
“In order to help Willie Huff, I had to set Delma up.
I told Delma that I wanted to rob a pharmacy to get
drugs and that I needed his gun to do it. I did not
really plan to commit a robbery but I told Delma this so
that he would give me his gun. . . . I convinced Delma
to drive to Dallas with me to get the gun.” App. 442–
443, ¶¶ 6–8.

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The defense presented no evidence. App. to Pet. for Cert.
A6. Banks was convicted of murder committed in the
course of a robbery, in violation of Tex. Penal Code Ann.
§ 19.03(a)(2) (1974). See App. to Pet. for Cert. C3.2
The penalty phase ran its course the next day. Ibid.
Governed by the Texas statutory capital murder scheme ap-
plicable in 1980, the jury decided Banks’s sentence by an-
swering three “special issues.” App. 142–143.3 “If the jury
unanimously answer[ed] ‘yes’ to each issue submitted, the
trial court [would be obliged to] sentence the defendant to
death.” Penry v. Lynaugh, 492 U. S. 302, 310 (1989) (con-
struing Texas’ sentencing scheme); Tex. Code Crim. Proc.
Ann., Arts. 37.071(c)–(e) (Vernon Supp. 1980). The critical
question at the penalty phase in Banks’s case was: “Do you
find from the evidence beyond a reasonable doubt that there
is a probability that the defendant, Delma Banks, Jr., would
commit criminal acts of violence that would constitute a con-
tinuing threat to society?” App. 143 (internal quotation
marks omitted).
On this question, the State offered two witnesses, Vetrano
Jefferson and Robert Farr. Id., at 104–113. Jefferson testi-
fied that, in early April 1980, Banks had struck him across
2 “A person commits an offense if he commits murder . . . and . . . the
person intentionally commits the murder in the course of committing or
attempting to commit kidnapping, burglary, robbery, aggravated rape, or
arson.” Tex. Penal Code Ann. § 19.03(a)(2) (1974).
3 As set forth in Texas law, the three special issues were:
“(1) whether the conduct of the defendant that caused the death of the
deceased was committed deliberately and with the reasonable expectation
that the death of the deceased or another would result;
“(2) whether there is a probability that the defendant would commit crimi-
nal acts of violence that would constitute a continuing threat to society;
and
“(3) if raised by the evidence, whether the conduct of the defendant in
killing the deceased was unreasonable in response to the provocation, if
any, by the deceased.” Tex. Code Crim. Proc. Ann., Arts. 37.071(b)(1)–(3)
(Vernon Supp. 1980).

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the face with a gun and threatened to kill him. Id., at 104–
106. Farr’s testimony focused once more on the trip to Dal-
las to fetch Banks’s gun. The gun was needed, Farr as-
serted, because “[w]e [Farr and Banks] were going to pull
some robberies.” Id., at 108. According to Farr, Banks
“said he would take care of it” if “there was any trouble
during these burglaries.” Id., at 109. When the prosecu-
tion asked: “How did [Banks] say he would take care of it?”
Farr responded: “[Banks] didn’t go into any specifics, but he
said it would be taken care of.” Ibid.
On cross-examination, defense counsel twice asked
whether Farr had told Deputy Sheriff Huff of the Dallas trip.
Ibid. The State remained silent as Farr twice perjuriously
testified: “No, I did not.” Ibid. Banks’s counsel also in-
quired whether Farr had previously attempted to obtain pre-
scription drugs by fraud, and, “up tight over that,” would
“testify to anything anybody want[ed] to hear.” Id., at 110.
Farr first responded: “Can you prove it?” Ibid. Instructed
by the court to answer defense counsel’s questions, Farr
again said: “No, I did not . . . .” Ibid.
Two defense witnesses impeached Farr, but were, in turn,
impeached themselves. James Kelley testified to Farr’s at-
tempts to obtain drugs by fraud; the prosecution impeached
Kelley by eliciting his close relationship to Banks’s girl-
friend. Id., at 124–129. Later, Kelley admitted to being
drunk while on the stand. App. to Pet. for Cert. A13. For-
mer Arkansas police officer Gary Owen testified that Farr,
as a police informant in Arkansas, had given false informa-
tion; the prosecution impeached Owen by bringing out his
pending application for employment by defense counsel’s pri-
vate investigator. App. 129–131.
Banks’s parents and acquaintances testified that Banks
was a “respectful, churchgoing young man.” App. to Pet.
for Cert. A7; App. 137–139. Thereafter, Banks took the
stand. He affirmed that he had “never before been con-

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victed of a felony.” Id., at 134.4 Banks admitted striking
Vetrano Jefferson in April 1980, and traveling to Dallas to
obtain a gun in late April 1980. Id., at 134–136. He denied,
however, any intent to participate in robberies, asserting
that Farr alone had planned to commit them. Id., at 136–
137. The prosecution suggested on cross-examination that
Banks had been willing “to supply [Farr] the means and pos-
sible death weapon in an armed robbery case.” Id., at 137.
Banks conceded as much. Ibid.
During summation, the prosecution intimated that Banks
had not been wholly truthful in this regard, suggesting that
“a man doesn’t travel two hundred miles, or whatever the
distance is from here [Texarkana] to Dallas, Texas, to supply
a person with a weapon.” Id., at 143. The State homed in
on Farr’s testimony that Banks said he would “take care” of
any trouble arising during the robbery:
“[Farr] said, ‘Man, you know, what i[f] there’s trouble?’
And [Banks] says, ‘Don’t worry about it. I’ll take care
of it.’ I think that speaks for itself, and I think you
know what that means. . . . I submit to you beyond a
reasonable doubt that the State has again met its burden
of proof, and that the answer to question number two
[propensity to commit violent criminal acts] should also
be yes.” Id., at 140, 144. See also id., at 146–147.
Urging Farr’s credibility, the prosecution called the jury’s
attention to Farr’s admission, at trial, that he used narcotics.
Id., at 36, 140. Just as Farr had been truthful about his
drug use, the prosecution suggested, he was also “open and
honest with [the jury] in every way” in his penalty-phase
testimony. Id., at 140. Farr’s testimony, the prosecution
emphasized, was “of the utmost significance” because it
4 Banks, in fact, had no criminal record at all. App. 255, ¶ 115; App. to
Pet. for Cert. C23. He also “had no history of violence or alcohol abuse
and seemed to possess a self-control that would suggest no particular risk
of future violence.” Ibid.

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showed “[Banks] is a danger to friends and strangers, alike.”
Id., at 146. Banks’s effort to impeach Farr was ineffective,
the prosecution further urged, because defense witness “Kel-
ley kn[ew] nothing about the murder,” and defense witness
Owen “wish[ed] to please his future employers.” Id., at 148.
The jury answered yes to the three special issues, and the
judge sentenced Banks to death. The Texas Court of Crimi-
nal Appeals denied Banks’s direct appeal. 643 S. W. 2d, at
135. Banks’s first two state postconviction motions raised
issues not implicated here; both were denied. Ex parte
Banks, No. 13568–01 (Tex. Crim. App. 1984); Ex parte
Banks, 769 S. W. 2d 539, 540 (Tex. Crim. App. 1989).
Banks’s third state postconviction motion, filed January 13,
1992, presented questions later advanced in federal court and
reiterated in the petition now before us. App. 150. Banks
alleged “upon information and belief ” that “the prosecution
knowingly failed to turn over exculpatory evidence as re-
quired by [Brady v. Maryland, 373 U. S. 83 (1963)]”; 5 the
withheld evidence, Banks asserted, “would have revealed
Robert Farr as a police informant and Mr. Banks’ arrest as a
set-up.” App. 180, ¶ 114 (internal quotation marks omitted).
In support of this third state-court postconviction plea,
Banks attached an unsigned affidavit from his girlfriend,
Farr’s sister-in-law Demetra Jefferson, which stated that
Farr “was well-connected to law enforcement people,” and
consequently managed to stay out of “trouble” for illegally
obtaining prescription drugs. Id., at 195, ¶ 7. Banks al-
leged as well that during the guilt phase of his trial, the
State deliberately withheld information “critical to the jury’s
assessment of Cook’s credibility,” including the “generous
5 Brady v. Maryland, 373 U. S. 83, 87 (1963), held that “the suppression
by the prosecution of evidence favorable to an accused upon request vio-
lates due process where the evidence is material either to guilt or to pun-
ishment, irrespective of the good faith or bad faith of the prosecution.”

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‘deal’ [Cook had] cut with the prosecutors.” Id., at 152, ¶ 2,
180, ¶ 114.6
The State’s reply to Banks’s pleading, filed October 6, 1992,
“denie[d] each and every allegation of fact made by [Banks],
except those supported by official court records and those
specifically admitted.” Id., at 234; Tr. of Oral Arg. 32.
“[N]othing was kept secret from the defense,” the State rep-
resented. App. 234. While the reply specifically asserted
that the State had made “no deal with Cook,” ibid., the State
said nothing specific about Farr. Affidavits from Deputy
Sheriff Huff and prosecutors accompanied the reply. Id., at
241–243. The affiants denied any “deal, secret or otherwise,
with Charles Cook,” but they, too, like the State’s pleading
they supported, remained silent about Farr. Ibid.
In February and July 1993 orders, the state postconviction
court rejected Banks’s claims. App. to Pet. for Cert. E1–E9,
G1–G7. The court found that “there was no agreement be-
tween the State and the witness Charles Cook,” but made
no findings concerning Farr. Id., at G2. In a January 10,
1996, one-page per curiam order, the Texas Court of Crimi-
nal Appeals upheld the lower court’s disposition of Banks’s
motion. Id., at D1.
On March 7, 1996, Banks filed the instant petition for a
writ of habeas corpus in the United States District Court
for the Eastern District of Texas. App. 248. He alleged
multiple violations of his federal constitutional rights. App.
to Pet. for Cert. C5–C7. Relevant here, Banks reasserted
that the State had withheld material exculpatory evi-
6 Banks also alleged ineffective assistance of counsel at both the guilt
and penalty phases; insufficient evidence on the second penalty-phase spe-
cial issue (Banks’s propensity to commit violent criminal acts); and the
exclusion of minority jurors in violation of Swain v. Alabama, 380 U. S.
202 (1965). App. to Pet. for Cert. C5–C7. Banks filed two further state
postconviction motions; both were denied. Brief for Respondent 6–7,
nn. 6 and 7 (citing Ex parte Banks, No. 13568–03 (Tex. Crim. App. 1993)
(per curiam), and Ex parte Banks, No. 13568–06 (Tex. Crim. App.), cert.
denied, 538 U. S. 990 (2003)).

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dence “reveal[ing] Robert Farr as a police informant and
Mr. Banks’ arrest as a set-up.” App. 260, ¶ 152 (internal
quotation marks omitted). Banks also asserted that the
State had concealed “Cook’s enormous incentive to testify in
a manner favorable to the [prosecution].” Id., at 260, ¶ 153;
App. to Pet. for Cert. C6–C7.7 In June 1998, Banks moved
for discovery and an evidentiary hearing to gain information
from the State on the roles played and trial testimony pro-
vided by Farr and Cook. App. 262–266, 282–283, 286. The
superintending Magistrate Judge allowed limited discovery
regarding Cook, but found insufficient justification for inquir-
ies concerning Farr. Id., at 294–295.
Banks renewed his discovery and evidentiary hearing re-
quests in February 1999. Id., at 2, 300–331. This time,
he proffered affidavits from both Farr and Cook to back up
his claims that, as to each of these two key witnesses, the
prosecution had wrongly withheld crucial exculpatory and
impeaching evidence. Id., at 322–331. Farr’s affidavit af-
firmed that Farr had “set Delma up” by proposing the drive
to Dallas and informing Deputy Sheriff Huff of the trip. Id.,
at 329, ¶ 8, 442–443, ¶ 8; supra, at 678. Accounting for his
unavailability earlier, Farr stated that less than a year after
the Banks trial, he had left Texarkana, first for Oklahoma,
then for California, because his police-informant work endan-
gered his life. App. 330–331, 444; Pet. for Cert. 27, n. 12.
Cook recalled that in preparation for his Banks trial testi-
mony, he had participated in “three or four . . . practice ses-
sions” at which prosecutors told him to testify “as they
wanted [him] to, and that [he] would spend the rest of [his]
life in prison if [he] did not.” App. 325, ¶¶ 10–11.
On March 4, 1999, the Magistrate Judge issued an order
establishing issues for an evidentiary hearing, id., at 340,
346, at which she would consider Banks’s claims that the
State had withheld “crucial exculpatory and impeaching evi-
7 We hereinafter refer to these claims as the Farr Brady and Cook
Brady claims respectively. See supra, at 682, n. 5.

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dence” concerning “two of the [S]tate’s essential witnesses,
Charles Cook and Robert Farr,” id., at 340, 345 (internal
quotation marks omitted). In anticipation of the hearing,
the Magistrate Judge ordered disclosure of the Bowie
County District Attorney’s files. Brief for Petitioner 37–38;
Tr. of June 7–8, 1999, Federal Evidentiary Hearing (ED
Tex.), p. 30 (hereinafter Federal Evidentiary Hearing).
One item lodged in the District Attorney’s files, turned
over to Banks pursuant to the Magistrate Judge’s disclosure
order, was a 74-page transcript of a Cook interrogation.
App. to Pet. for Cert. A10. The interrogation, conducted
by Bowie County law enforcement officials and prosecutors,
occurred in September 1980, shortly before the Banks trial.
Ibid. The transcript revealed that the State’s representa-
tives had closely rehearsed Cook’s testimony. In particular,
the officials told Cook how to reconcile his testimony with
affidavits to which he had earlier subscribed recounting
Banks’s visits to Dallas. See, e. g., Joint Lodging Material
24 (“Your [April 1980] statement is obviously screwed
up.”); id., at 26 (“[T]he way this statement should read is
that . . . .”); id., at 32 (“[L]et me tell you how this is going to
work.”); id., at 36 (“That’s not in your [earlier] statement.”).
Although the transcript did not bear on Banks’s claim that
the prosecution had a deal with Cook, it provided compelling
evidence that Cook’s testimony had been tutored by Banks’s
prosecutors. Without objection at the hearing, the Magis-
trate Judge admitted the September 1980 transcript into evi-
dence. Brief for Petitioner 39; Federal Evidentiary Hear-
ing 75–76.
Testifying at the evidentiary hearing, Deputy Sheriff Huff
acknowledged, for the first time, that Farr was an informant
and that he had been paid $200 for his involvement in the
case. App. to Pet. for Cert. C43. As to Cook, a Banks trial
prosecutor testified, in line with the State’s consistent posi-
tion, that no deal had been offered to gain Cook’s trial tes-
timony. Id., at C45; Federal Evidentiary Hearing 52–53.

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Defense counsel questioned the prosecutor about the Sep-
tember 1980 transcript, calling attention to discrepancies be-
tween the transcript and Cook’s statements at trial. Id., at
65–68. In a posthearing brief and again in proposed find-
ings of fact and conclusions of law, Banks emphasized the
suppression of the September 1980 transcript, noting the
prosecution’s obligation to disclose material, exculpatory evi-
dence, and the assurance in this case that Banks would re-
ceive “all [the] discovery to which [Banks was] entitled.”
App. 360–361, and n. 1, 378–379 (internal quotation marks
omitted); supra, at 677.
In a May 11, 2000, report and recommendation, the Magis-
trate Judge recommended a writ of habeas corpus with
respect to Banks’s death sentence, but not his conviction.
App. to Pet. for Cert. C54. “[T]he State’s failure to disclose
Farr’s informant status, coupled with trial counsel’s dismal
performance during the punishment phase,” the Magistrate
Judge concluded, “undermined the reliability of the jury’s
verdict regarding punishment.” Id., at C44. Finding no
convincing evidence of a deal between the State and Cook,
however, she recommended that the guilt-phase verdict re-
main undisturbed. Id., at C46.
Banks moved to alter or amend the Magistrate Judge’s
report on the ground that it left unresolved a fully aired
question, i. e., whether Banks’s rights were violated by the
State’s failure to disclose to the defense the prosecution’s
eve-of-trial interrogation of Cook. App. 398. That interro-
gation, Banks observed, could not be reconciled with Cook’s
insistence at trial that he had talked to no one about his
testimony. Id., at 400, n. 17; see supra, at 677.
The District Court adopted the Magistrate Judge’s report
and denied Banks’s motion to amend the report. App. to
Pet. for Cert. B6; App. 421–424. Concerning the Cook
Brady transcript-suppression claim, the District Court rec-
ognized that Banks had filed his federal petition in 1996,
three years before he became aware of the September 1980

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transcript. App. 422–423. When the transcript surfaced in
response to the Magistrate Judge’s 1999 disclosure order,
Banks raised that newly discovered, long withheld document
in his proposed findings of fact and conclusions of law and,
again, in his objections to the Magistrate Judge’s report.
Id., at 423. The District Court concluded, however, that
Banks had not properly pleaded a Brady claim predicated on
the withheld Cook rehearsal transcript. App. 422. When
that Brady claim came to light, the District Court reasoned,
Banks should have moved to amend or supplement his 1996
federal habeas petition specifically to include the 1999 discov-
ery as a basis for relief. App. 423. Banks urged that a
Brady claim based on the September 1980 transcript had
been aired by implied consent; under Federal Rule of Civil
Procedure 15(b), he contended, the claim should have been
treated as if raised in the pleadings. App. 433.8 Banks
sought, and the District Court denied, a certificate of appeal-
ability on this question. Id., at 433, 436.
In an August 20, 2003, unpublished per curiam opinion,
the Court of Appeals for the Fifth Circuit reversed the judg-
ment of the District Court to the extent that it granted relief
on the Farr Brady claim and denied a certificate of appeal-
ability on the Cook Brady claim. App. to Pet. for Cert. A2,
judgt. order reported at 48 Fed. Appx. 104 (2002).9 The
8 Federal Rule of Civil Procedure 15(b) provides: “When issues not
raised by the pleadings are tried by express or implied consent of the
parties, they shall be treated in all respects as if they had been raised in
the pleadings. Such amendment of the pleadings as may be necessary to
cause them to conform to the evidence and to raise these issues may be
made upon motion of any party at any time . . . .” Rule 11 of the Rules
Governing Section 2254 Cases in the United States District Courts pro-
vides that the Federal Rules of Civil Procedure apply “to the extent that
they are not inconsistent with [habeas] rules.”
9 The Fifth Circuit noted correctly that under Lindh v. Murphy, 521
U. S. 320, 336–337 (1997), the standards of the Antiterrorism and Effective
Death Penalty Act of 1996 (AEDPA), 110 Stat. 1214, do not apply to
Banks’s petition. See App. to Pet. for Cert. A14–A15.

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Court of Appeals observed that in his 1992 state-court post-
conviction application, Banks had not endeavored to develop
the facts underpinning the Farr Brady claim. App. to Pet.
for Cert. A19–A20. For that reason, the court held, the evi-
dentiary proceeding ordered by the Magistrate Judge was
unwarranted. Ibid. The Court of Appeals expressed no
doubt that the prosecution had suppressed, prior to the fed-
eral habeas proceeding, Farr’s informant status and his part
in the fateful trip to Dallas. But Banks was not appropri-
ately diligent in pursuing his state-court application, the
Court of Appeals maintained. In the Fifth Circuit’s view,
Banks should have at that time attempted to locate Farr and
question him; similarly, he should have asked to interview
Deputy Sheriff Huff and other officers involved in investigat-
ing the crime. Id., at A19, A22. If such efforts had proved
unavailing, the Court of Appeals suggested, Banks might
have applied to the state court for assistance. Id., at A19.
Banks’s lack of diligence in pursuing his 1992 state-court
plea, the Court of Appeals concluded, rendered the evidence
uncovered in the federal habeas proceeding procedurally
barred. Id., at A22–A23.
In any event, the Fifth Circuit further concluded, Farr’s
status as an informant was not “materia[l]” for Brady pur-
poses. App. to Pet. for Cert. A32–A33. Banks had im-
peached Farr at trial by bringing out that he had been a
police informant in Arkansas, and an unreliable one at that.
Id., at A28, A32–A33; supra, at 680. Moreover, the Court
of Appeals said, other witnesses had corroborated much of
Farr’s testimony against Banks. App. to Pet. for Cert. A32.
Notably, Banks himself had acknowledged his willingness to
get a gun for Farr’s use in robberies. Ibid. In addition,
the Fifth Circuit observed, the Magistrate Judge had relied
on the cumulative effect of Brady error and the ineffective-
ness of Banks’s counsel at the penalty phase. App. to Pet.
for Cert. A44. Banks himself, however, had not urged that
position; he had argued Brady and ineffective assistance of

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counsel discretely, not cumulatively. App. to Pet. for Cert.
A46–A47. Finally, in accord with the District Court, the
Court of Appeals apparently regarded Rule 15(b) as inappli-
cable in habeas proceedings. App. to Pet. for Cert. A51–
A52. The Fifth Circuit accordingly denied a certificate of
appealability on the Cook Brady transcript-suppression
claim. App. to Pet. for Cert. A52, A78.
With an execution date set for March 12, 2003, Banks ap-
plied to this Court for a writ of certiorari, presenting four
issues: the tenability of his Farr Brady claim; a penalty-
phase ineffective-assistance-of-counsel claim; the question
whether, as to the Cook Brady transcript-suppression claim,
a certificate of appealability was wrongly denied; and a claim
of improper exclusion of minority jurors in violation of
Swain v. Alabama, 380 U. S. 202 (1965). Pet. for Cert. 23–
24. We stayed Banks’s execution on March 12, 2003, 538
U. S. 917, and, on April 21, 2003, granted his petition on all
questions other than his Swain claim. 538 U. S. 977. We
now reverse the Court of Appeals’ judgment dismissing
Banks’s Farr Brady claim and that Court’s denial of a cer-
tificate of appealability on his Cook Brady claim.10
II
We note, initially, that Banks’s Brady claims arose under
the regime in place prior to the Antiterrorism and Effective
Death Penalty Act of 1996 (AEDPA), 110 Stat. 1214. Turn-
ing to the tenability of those claims, we consider first Banks’s
Farr Brady claim as it trains on his death sentence, see App.
to Pet. for Cert. B6 (District Court granted habeas solely
with respect to the capital sentence), and next, Banks’s Cook
Brady claim.
10 Our disposition of the Farr Brady claim, and our conclusion that a writ
of habeas corpus should issue with respect to the death sentence, render
it unnecessary to address Banks’s claim of ineffective assistance of counsel
at the penalty phase; any relief he could obtain on that claim would be
cumulative.

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690 BANKS v. DRETKE
Opinion of the Court
A
To pursue habeas corpus relief in federal court, Banks first
had to exhaust “the remedies available in the courts of the
State.” 28 U. S. C. § 2254(b) (1994 ed.); see Rose v. Lundy,
455 U. S. 509, 520 (1982). Banks alleged in his January 1992
state-court application for a writ of habeas corpus that the
prosecution knowingly failed to turn over exculpatory evi-
dence involving Farr in violation of Banks’s due process
rights. App. 180. Banks thus satisfied the exhaustion re-
quirement as to the legal ground for his Farr Brady claim.11
In state postconviction court, however, Banks failed to
produce evidence establishing that Farr had served as a po-
lice informant in this case. As support for his Farr Brady
claim, Banks appended to his state-court application only De-
metra Jefferson’s hardly probative statement that Farr “was
well-connected to law enforcement people.” App. 195, ¶ 7;
see supra, at 682. In the federal habeas forum, therefore,
it was incumbent on Banks to show that he was not barred,
by reason of the anterior state proceedings, from produc-
ing evidence to substantiate his Farr Brady claim. Banks
“[would be] entitled to an evidentiary hearing [in federal
court] if he [could] show cause for his failure to develop the
11 Banks’s federal habeas petition, the Court of Appeals said, stated a
claim, only under Brady, that material exculpatory or impeachment evi-
dence had been suppressed, not a claim under Napue v. Illinois, 360 U. S.
264 (1959), and Giglio v. United States, 405 U. S. 150 (1972), that the prose-
cution had failed to correct Farr’s false testimony. App. to Pet. for Cert.
A29–A32; App. 259–260. In its view, the Court of Appeals explained, a
Brady claim is distinct from a Giglio claim, App. to Pet. for Cert. A30;
thus the two did not fit under one umbrella. But cf. United States v.
Bagley, 473 U. S. 667, 679–680, n. 8 (1985); United States v. Agurs, 427
U. S. 97, 103–104 (1976). On brief, the parties debate the issue. Brief for
Petitioner 23–25; Brief for Respondent 21–22, n. 21. Because we conclude
that Banks qualifies for relief under Brady, we need not decide whether a
Giglio claim, to warrant adjudication, must be separately pleaded.

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facts in state-court proceedings and actual prejudice result-
ing from that failure.” Keeney v. Tamayo-Reyes, 504 U. S.
1, 11 (1992).
Brady, we reiterate, held that “the suppression by the
prosecution of evidence favorable to an accused upon request
violates due process where the evidence is material either to
guilt or to punishment, irrespective of the good faith or bad
faith of the prosecution.” 373 U. S., at 87. We set out in
Strickler v. Greene, 527 U. S. 263, 281–282 (1999), the three
components or essential elements of a Brady prosecutorial
misconduct claim: “The evidence at issue must be favorable
to the accused, either because it is exculpatory, or because it
is impeaching; that evidence must have been suppressed by
the State, either willfully or inadvertently; and prejudice
must have ensued.” 527 U. S., at 281–282. “[C]ause and
prejudice” in this case “parallel two of the three components
of the alleged Brady violation itself.” Id., at 282. Cor-
responding to the second Brady component (evidence sup-
pressed by the State), a petitioner shows “cause” when the
reason for his failure to develop facts in state-court proceed-
ings was the State’s suppression of the relevant evidence;
coincident with the third Brady component (prejudice), prej-
udice within the compass of the “cause and prejudice” re-
quirement exists when the suppressed evidence is “material”
for Brady purposes. 527 U. S., at 282. As to the first
Brady component (evidence favorable to the accused), be-
yond genuine debate, the suppressed evidence relevant here,
Farr’s paid informant status, qualifies as evidence advanta-
geous to Banks. See App. to Pet. for Cert. A26 (Court of
Appeals’ recognition that “Farr’s being a paid informant
would certainly be favorable to Banks in attacking Farr’s
testimony”). Thus, if Banks succeeds in demonstrating
“cause and prejudice,” he will at the same time succeed in
establishing the elements of his Farr Brady death penalty
due process claim.

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692 BANKS v. DRETKE
Opinion of the Court
B
Our determination as to “cause” for Banks’s failure to de-
velop the facts in state-court proceedings is informed by
Strickler.12 In that case, Virginia prosecutors told the peti-
tioner, prior to trial, that “the prosecutor’s files were open
to the petitioner’s counsel,” thus “there was no need for
a formal [Brady] motion.” 527 U. S., at 276, n. 14 (quot-
ing App. in Strickler v. Greene, O. T. 1998, No. 98–5864,
pp. 212–213 (brackets in original)). The prosecution file
given to the Strickler petitioner, however, did not include
several documents prepared by an “importan[t]” prosecution
witness, recounting the witness’ initial difficulty recalling
the events to which she testified at the petitioner’s trial.
527 U. S., at 273–275, 290. Those absent-from-the-file docu-
ments could have been used to impeach the witness. Id., at
273. In state-court postconviction proceedings, the Strick-
ler petitioner had unsuccessfully urged ineffective assistance
of trial counsel based on counsel’s failure to move, pretrial,
for Brady material. Answering that plea, the State as-
serted that a Brady motion would have been superfluous, for
the prosecution had maintained an open file policy pursuant
to which it had disclosed all Brady material. 527 U. S., at
276, n. 14, 278.
This Court determined that in the federal habeas proceed-
ings, the Strickler petitioner had shown cause for his failure
to raise a Brady claim in state court. 527 U. S., at 289.
Three factors accounted for that determination:
“(a) the prosecution withheld exculpatory evidence;
(b) petitioner reasonably relied on the prosecution’s open
file policy as fulfilling the prosecution’s duty to disclose
such evidence; and (c) the [State] confirmed petitioner’s
reliance on the open file policy by asserting during state
12 Surprisingly, the Court of Appeals’ per curiam opinion did not refer
to Strickler v. Greene, 527 U. S. 263 (1999), the controlling precedent on
the issue of “cause.” App. to Pet. for Cert. A15–A33.

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habeas proceedings that petitioner had already received
everything known to the government.” Ibid. (internal
quotation marks omitted).13
This case is congruent with Strickler in all three respects.
First, the State knew of, but kept back, Farr’s arrangement
with Deputy Sheriff Huff. App. to Pet. for Cert. C43; Tr. of
Oral Arg. 33; cf. Kyles v. Whitley, 514 U. S. 419, 437 (1995)
(prosecutors are responsible for “any favorable evidence
known to the others acting on the government’s behalf in the
case, including the police”). Second, the State asserted, on
the eve of trial, that it would disclose all Brady material.
App. 361, n. 1; see supra, at 677. As Strickler instructs,
Banks cannot be faulted for relying on that representation.
See 527 U. S., at 283–284 (an “open file policy” is one factor
that “explain[s] why trial counsel did not advance [a Brady]
claim”).
Third, in his January 1992 state habeas application, Banks
asserted that Farr was a police informant and Banks’s arrest,
“a set-up.” App. 180, ¶ 114 (internal quotation marks omit-
ted). In its answer, the State denied Banks’s assertion.
Id., at 234; see supra, at 683. The State thereby “con-
firmed” Banks’s reliance on the prosecution’s representation
that it had fully disclosed all relevant information its file
contained. 527 U. S., at 289; see id., at 284 (state habeas
counsel, as well as trial counsel, could reasonably rely on the
State’s representations). In short, because the State per-
sisted in hiding Farr’s informant status and misleadingly
represented that it had complied in full with its Brady disclo-
sure obligations, Banks had cause for failing to investigate,
in state postconviction proceedings, Farr’s connections to
Deputy Sheriff Huff.
13 We left open the question “whether any one or two of these factors
would be sufficient to constitute cause.” Strickler, 527 U. S., at 289. We
need not decide that question today.

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On the question of “cause,” moreover, Banks’s case is
stronger than was the petitioner’s in Strickler in a notable
respect. As a prosecution witness in the guilt and penalty
phases of Banks’s trial, Farr repeatedly misrepresented his
dealings with police; each time Farr responded untruthfully,
the prosecution allowed his testimony to stand uncorrected.
See supra, at 678–680. Farr denied taking money from or
being promised anything by police officers, App. 37; he twice
denied speaking with police officers, id., at 38, and twice de-
nied informing Deputy Sheriff Huff about Banks’s trip to
Dallas, id., at 109. It has long been established that the
prosecution’s “deliberate deception of a court and jurors by
the presentation of known false evidence is incompatible
with rudimentary demands of justice.” Giglio v. United
States, 405 U. S. 150, 153 (1972) (quoting Mooney v. Holohan,
294 U. S. 103, 112 (1935) (per curiam) (internal quotation
marks omitted)). If it was reasonable for Banks to rely on
the prosecution’s full disclosure representation, it was also
appropriate for Banks to assume that his prosecutors would
not stoop to improper litigation conduct to advance prospects
for gaining a conviction. See Berger v. United States, 295
U. S. 78, 88 (1935); Strickler, 527 U. S., at 284.14
The State presents three main arguments for distinguish-
ing Strickler on the issue of “cause,” two of them endorsed
14 In addition, Banks could have expected disclosure of Farr’s informant
status as a matter of state law if Farr in fact acted in that capacity.
Under Texas law applicable at the time of Banks’s trial, the State had an
obligation to disclose the identity of an informant when “the informant . . .
was present at the time of the offense or arrest . . . [or] was otherwise
shown to be a material witness to the transaction . . . .” Kemner v. State,
589 S. W. 2d 403, 408 (Tex. Crim. App. 1979) (quoting Carmouche v. State,
540 S. W. 2d 701, 703 (Tex. Crim. App. 1976)); cf. Tex. Rule Evid. 508(c)(1)
(2003) (“No privilege exists [for the identity of an informer] . . . if the
informer appears as a witness for the public entity.”). Farr was present
when Banks was arrested. App. 443, ¶ 10. Further, as the prosecution
noted in its penalty-phase summation, Farr’s testimony was not only ma-
terial, but “of the utmost significance.” Id., at 146.

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by the Court of Appeals. Brief for Respondent 15–20; App.
to Pet. for Cert. A19, A22–A23; see supra, at 687–688. We
conclude that none of these arguments accounts adequately
for the State’s concealment and misrepresentation regarding
Farr’s link to Deputy Sheriff Huff. The State first suggests
that Banks’s failure, during state postconviction proceedings,
to “attempt to locate Farr and ascertain his true status,” or
to “interview the investigating officers, such as Deputy Huff,
to ascertain Farr’s status,” undermines a finding of cause;
the Fifth Circuit agreed. App. to Pet. for Cert. A22; Brief
for Respondent 18–20. In the State’s view, “[t]he question
[of cause] revolves around Banks’s conduct,” particularly his
lack of appropriate diligence in pursuing the Farr Brady
claim before resorting to federal court. Brief for Respond-
ent 14.15
We rejected a similar argument in Strickler. There, the
State contended that examination of a witness’ trial testi-
mony, alongside a letter the witness published in a local
newspaper, should have alerted the petitioner to the exist-
ence of undisclosed interviews of the witness by the police.
527 U. S., at 284, and n. 26. We found this contention insub-
stantial. In light of the State’s open file policy, we noted, “it
is especially unlikely that counsel would have suspected that
additional impeaching evidence was being withheld.” Id.,
at 285. Our decisions lend no support to the notion that
defendants must scavenge for hints of undisclosed Brady ma-
terial when the prosecution represents that all such material
has been disclosed. As we observed in Strickler, defense
counsel has no “procedural obligation to assert constitutional
error on the basis of mere suspicion that some prosecutorial
15 The Court of Appeals also stated that, because “the State did not
respond” to Banks’s “Farr-was-an-informant contention” in its answer to
the January 1992 state habeas application, Banks should have “further
investigate[d].” App. to Pet. for Cert. A22. The Fifth Circuit’s error in
this regard is apparent. As earlier recounted, see supra, at 683, the
State’s answer indeed did deny Banks’s allegation.

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misstep may have occurred.” 527 U. S., at 286–287. The
“cause” inquiry, we have also observed, turns on events or
circumstances “external to the defense.” Amadeo v. Zant,
486 U. S. 214, 222 (1988) (quoting Murray v. Carrier, 477
U. S. 478, 488 (1986)).
The State here nevertheless urges, in effect, that “the
prosecution can lie and conceal and the prisoner still has the
burden to . . . discover the evidence,” Tr. of Oral Arg. 35, so
long as the “potential existence” of a prosecutorial miscon-
duct claim might have been detected, id., at 36. A rule thus
declaring “prosecutor may hide, defendant must seek,” is not
tenable in a system constitutionally bound to accord defend-
ants due process. “Ordinarily, we presume that public offi-
cials have properly discharged their official duties.” Bracy
v. Gramley, 520 U. S. 899, 909 (1997) (quoting United States
v. Chemical Foundation, Inc., 272 U. S. 1, 14–15 (1926) (in-
ternal quotation marks omitted)). We have several times
underscored the “special role played by the American prose-
cutor in the search for truth in criminal trials.” Strickler,
527 U. S., at 281; accord Kyles, 514 U. S., at 439–440; United
States v. Bagley, 473 U. S. 667, 675, n. 6 (1985); Berger, 295
U. S., at 88. See also Olmstead v. United States, 277 U. S.
438, 484 (1928) (Brandeis, J., dissenting). Courts, litigants,
and juries properly anticipate that “obligations [to refrain
from improper methods to secure a conviction] . . . plainly
rest[ing] upon the prosecuting attorney, will be faithfully
observed.” Berger, 295 U. S., at 88. Prosecutors’ dishon-
est conduct or unwarranted concealment should attract no
judicial approbation. See Kyles, 514 U. S., at 440 (“The
prudence of the careful prosecutor should not . . . be
discouraged.”).
The State’s second argument is a variant of the first. Spe-
cifically, the State argues, and the Court of Appeals ac-
cepted, that Banks cannot show cause because in the 1992
state-court postconviction proceedings, he failed to move for
investigative assistance enabling him to inquire into Farr’s

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police connections, connections he then alleged, but failed to
prove. Brief for Respondent 15–16; App. to Pet. for Cert.
A19; see 1977 Tex. Gen. Laws ch. 789, § 2(d) (as amended)
(instructing postconviction court to “designat[e] the issues of
fact to be resolved,” and giving the court discretion to “order
affidavits, depositions, interrogatories, and hearings”).
Armed in 1992 only with Demetra Jefferson’s declaration
that Farr was “well-connected to law enforcement people,”
App. 195, ¶ 7; see supra, at 682, Banks had little to proffer
in support of a request for assistance from the state post-
conviction court. We assign no overriding significance to
Banks’s failure to invoke state-court assistance to which he
had no clear entitlement. Cf. Strickler, 527 U. S., at 286
(“Proper respect for state procedures counsels against a re-
quirement that all possible claims be raised in state collateral
proceedings, even when no known facts support them.”).16
Finally, relying on Roviaro v. United States, 353 U. S. 53
(1957), the State asserts that “disclosure [of an informant’s
identity] is not automatic,” and, “[c]onsequently, it was
Banks’s duty to move for disclosure of otherwise privileged
material.” Brief for Respondent 17–18, n. 15. We need not
linger over this argument. The issue of evidentiary law in
Roviaro was whether (or when) the Government is obliged
to reveal the identity of an undercover informer the Govern-
ment does not call as a trial witness. 353 U. S., at 55–56.
The Court there stated that no privilege obtains “[w]here
the disclosure of an informer’s identity, or of the contents of
his communication, is relevant and helpful to the defense of
an accused.” Id., at 60–61. Accordingly, even though the
informer in Roviaro did not testify, we held that disclosure
16 Furthermore, rather than conceding the need for factual development
of the Farr Brady claim in state postconviction court, the State asserted
that Banks’s prosecutorial misconduct claims were meritless and procedur-
ally barred in that tribunal. App. 234, 240. Having taken that position
in 1992, the State can hardly fault Banks now for failing earlier to request
assistance the State certainly would have opposed.

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of his identity was necessary because he could have “ampli-
f[ied] or contradict[ed] the testimony of government wit-
nesses.” Id., at 64.
Here, the State elected to call Farr as a witness. Indeed,
he was a key witness at both guilt and punishment phases of
Banks’s capital trial. Farr’s status as a paid informant was
unquestionably “relevant”; similarly beyond doubt, disclo-
sure of Farr’s status would have been “helpful to [Banks’s]
defense.” Id., at 60–61. Nothing in Roviaro, or any other
decision of this Court, suggests that the State can examine
an informant at trial, withholding acknowledgment of his in-
formant status in the hope that defendant will not catch on,
so will make no disclosure motion.
In summary, Banks’s prosecutors represented at trial and
in state postconviction proceedings that the State had held
nothing back. Moreover, in state postconviction court, the
State’s pleading denied that Farr was an informant. App.
234; supra, at 683. It was not incumbent on Banks to prove
these representations false; rather, Banks was entitled to
treat the prosecutor’s submissions as truthful. Accordingly,
Banks has shown cause for failing to present evidence in
state court capable of substantiating his Farr Brady claim.
C
Unless suppressed evidence is “material for Brady pur-
poses, [its] suppression [does] not give rise to sufficient prej-
udice to overcome [a] procedural default.” Strickler, 527
U. S., at 282 (internal quotation marks omitted). Our touch-
stone on materiality is Kyles v. Whitley, 514 U. S. 419 (1995).
Kyles instructed that the materiality standard for Brady
claims is met when “the favorable evidence could reasonably
be taken to put the whole case in such a different light as
to undermine confidence in the verdict.” 514 U. S., at 435.
See also id., at 434–435 (“A defendant need not demonstrate
that after discounting the inculpatory evidence in light of the
undisclosed evidence, there would not have been enough left

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to convict.”); accord Strickler, 527 U. S., at 290. In short,
Banks must show a “reasonable probability of a different
result.” Kyles, 514 U. S., at 434 (internal quotation marks
omitted) (citing Bagley, 473 U. S., at 678).
As the State acknowledged at oral argument, Farr was
“paid for a critical role in the scenario that led to the indict-
ment.” Tr. of Oral Arg. 34. Farr’s declaration, presented
to the federal habeas court, asserts that Farr, not Banks,
initiated the proposal to obtain a gun to facilitate the com-
mission of robberies. See App. 442–443, ¶¶ 7–8; supra, at
678. Had Farr not instigated, upon Deputy Sheriff Huff ’s
request, the Dallas excursion to fetch Banks’s gun, the pros-
ecution would have had slim, if any, evidence that Banks
planned to “continue” committing violent acts. App. 147.17
Farr’s admission of his instigating role, moreover, would
have dampened the prosecution’s zeal in urging the jury to
bear in mind Banks’s “planning and acquisition of a gun to
commit robbery,” or Banks’s “planned violence.” Ibid.; see
Tr. of Oral Arg. 50.18
17 It bears reiteration here that Banks had no criminal record, id., at
255, ¶ 115, “no history of violence or alcohol abuse,” nothing indicative of
“[any] particular risk of future violence,” App. to Pet. for Cert. C23.
It also appears that the remaining prosecution witness in the penalty
phase, Vetrano Jefferson, had omitted crucial details from his 1980 testi-
mony. In his September 1980 testimony, Vetrano Jefferson said that
Banks had struck him with a pistol in early April 1980. App. 104–105;
supra, at 679–680. In the federal habeas proceeding, Vetrano Jefferson
elaborated that he, not Banks, had initiated that incident by making “dis-
respectful comments” about Demetra Jefferson, Banks’s girlfriend. App.
337, ¶ 4. Vetrano Jefferson recounted that he “grew angry” when Banks
objected to the comments, and only then did a fight ensue, in the course
of which Banks struck Vetrano Jefferson. Ibid.
18 On brief and at oral argument, the State suggests that “the damaging
evidence was Banks’s willing abetment of Farr’s commission of a violent
crime, not Banks’s own intent to commit such an act.” Brief for Respond-
ent 25 (emphasis in original); Tr. of Oral Arg. 50. See also post, at 707–708
(Thomas, J., concurring in part and dissenting in part). In the penalty-
phase summation, however, the prosecution highlighted Banks’s propen-

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Because Banks had no criminal record, Farr’s testimony
about Banks’s propensity to commit violent acts was crucial
to the prosecution. Without that testimony, the State could
not have underscored, as it did three times in the penalty
phase, that Banks would use the gun fetched in Dallas to
“take care” of trouble arising during the robberies. App.
140, 144, 146–147; see supra, at 681. The stress placed by
the prosecution on this part of Farr’s testimony, uncorrobo-
rated by any other witness, belies the State’s suggestion that
“Farr’s testimony was adequately corroborated.” Brief for
Respondent 22–25. The prosecution’s penalty-phase sum-
mation, moreover, left no doubt about the importance the
State attached to Farr’s testimony. What Farr told the jury,
the prosecution urged, was “of the utmost significance” to
show “[Banks] is a danger to friends and strangers, alike.”
App. 146.
In Strickler, 527 U. S., at 289, although the Court found
“cause” for the petitioner’s procedural default of a Brady
claim, it found the requisite “prejudice” absent, 527 U. S.,
at 292–296. Regarding “prejudice,” the contrast between
Strickler and Banks’s case is marked. The witness whose
impeachment was at issue in Strickler gave testimony that
was in the main cumulative, id., at 292, and hardly significant
sity to commit violent criminal acts, see App. 140, 144, 146–147, not his
facilitation of others’ criminal acts, see id., at 141 (“[Banks] says, ‘I thought
I would give [the gun] to them so they could do the robberies.’ I don’t
believe you [the jury] believe that.”); id., at 143 (“a man doesn’t travel two
hundred miles . . . to supply [another] person with a weapon”). The spe-
cial issue the prosecution addressed focused on what acts Banks would
commit, not what harms he might facilitate: “Do you find from the evi-
dence beyond a reasonable doubt that there is a probability that the de-
fendant, Delma Banks, Jr., would commit criminal acts of violence that
would constitute a continuing threat to society?” Ibid. (internal quota-
tion marks omitted and emphasis added). It is therefore unsurprising
that the prosecution did not rest on Banks’s facilitation of others’ criminal
acts in urging the jury to answer the second special issue (propensity to
commit violent criminal acts) in the affirmative.

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to one of the “two predicates for capital murder: [armed]
robbery,” id., at 294. Other evidence in the record, the
Court found, provided strong support for the conviction even
if the witness’ testimony had been excluded entirely: Unlike
the Banks prosecution, in Strickler, “considerable forensic
and other physical evidence link[ed] [the defendant] to the
crime” and supported the capital murder conviction. Id., at
293. Most tellingly, the witness’ testimony in Strickler “did
not relate to [the petitioner’s] eligibility for the death sen-
tence”; it “was not relied upon by the prosecution at all dur-
ing its closing argument at the penalty phase.” Id., at 295.
In contrast, Farr’s testimony was the centerpiece of Banks’s
prosecution’s penalty-phase case.
Farr’s trial testimony, critical at the penalty phase, was
cast in large doubt by the declaration Banks ultimately ob-
tained from Farr and introduced in the federal habeas pro-
ceeding. See supra, at 678, 684. In the guilt phase of
Banks’s trial, Farr had acknowledged his narcotics use.
App. 36. In the penalty phase, Banks’s counsel asked Farr
if, “drawn up tight over” previous drug-related activity, he
would “testify to anything anybody want[ed] to hear”; Farr
denied this. Id., at 110; supra, at 680. Farr’s declaration
supporting Banks’s federal habeas petition, however, vividly
contradicts that denial: “I assumed that if I did not help
[Huff] . . . he would have me arrested for drug charges.”
App. 442, ¶ 6. Had jurors known of Farr’s continuing inter-
est in obtaining Deputy Sheriff Huff ’s favor, in addition to
his receipt of funds to “set [Banks] up,” id., at 442, ¶ 7, they
might well have distrusted Farr’s testimony, and, insofar as
it was uncorroborated, disregarded it.
The jury, moreover, did not benefit from customary, truth-
promoting precautions that generally accompany the testi-
mony of informants. This Court has long recognized the
“serious questions of credibility” informers pose. On Lee v.
United States, 343 U. S. 747, 757 (1952). See also Trott,
Words of Warning for Prosecutors Using Criminals as Wit-

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nesses, 47 Hastings L. J. 1381, 1385 (1996) (“Jurors suspect
[informants’] motives from the moment they hear about them
in a case, and they frequently disregard their testimony alto-
gether as highly untrustworthy and unreliable . . . .”). We
have therefore allowed defendants “broad latitude to probe
[informants’] credibility by cross-examination” and have
counseled submission of the credibility issue to the jury
“with careful instructions.” On Lee, 343 U. S., at 757; accord
Hoffa v. United States, 385 U. S. 293, 311–312 (1966). See
also 1A K. O’Malley, J. Grenig, & W. Lee, Federal Jury Prac-
tice and Instructions, Criminal § 15.02 (5th ed. 2000) ( jury
instructions from the First, Fifth, Sixth, Seventh, Eighth,
Ninth, and Eleventh Circuits on special caution appropriate
in assessing informant testimony).
The State argues that “Farr was heavily impeached [at
trial],” rendering his informant status “merely cumulative.”
Tr. of Oral Arg. 49; see Brief for Respondent 26–28; post, at
709, n. 3. The record suggests otherwise. Neither witness
called to impeach Farr gave evidence directly relevant to
Farr’s part in Banks’s trial. App. 124–133; id., at 129 (pro-
secutor noted that Kelley lacked “personal knowledge with
regard to this case on trial”). The impeaching witnesses,
Kelley and Owen, moreover, were themselves impeached, as
the prosecution stressed on summation. See id., at 141, 148;
supra, at 680, 682. Further, the prosecution turned to its
advantage remaining impeachment evidence concerning
Farr’s drug use. On summation, the prosecution suggested
that Farr’s admission “that he used dope, that he shot,” dem-
onstrated that Farr had been “open and honest with [the
jury] in every way.” App. 140; supra, at 681.
At least as to the penalty phase, in sum, one can hardly be
confident that Banks received a fair trial, given the jury’s
ignorance of Farr’s true role in the investigation and trial of
the case. See Kyles, 514 U. S., at 434 (“The question is not
whether the defendant would more likely than not have re-
ceived a different verdict with the evidence, but whether in

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its absence he received a fair trial, understood as a trial re-
sulting in a verdict worthy of confidence.”). On the record
before us, one could not plausibly deny the existence of the
requisite “reasonable probability of a different result” had
the suppressed information been disclosed to the defense.
Ibid. (internal quotation marks omitted) (citing Bagley, 473
U. S., at 678); Strickler, 527 U. S., at 290. Accordingly, as to
the suppression of Farr’s informant status and its bearing on
“the reliability of the jury’s verdict regarding punishment,”
App. to Pet. for Cert. C44; supra, at 686, all three elements
of a Brady claim are satisfied.
III
Both the District Court and the Court of Appeals denied
Banks a certificate of appealability with regard to his Cook
Brady claim, which rested on the prosecution’s suppression
of the September 1980 Cook interrogation transcript. App.
422–423; App. to Pet. for Cert. A52, A78; supra, at 687, 689.
See also Joint Lodging Material 1–36. The District Court
and the Fifth Circuit concluded that Banks had not properly
pleaded this claim because he had not sought leave to amend
his petition, but had stated the claim only in other submis-
sions, i. e., in his proposed findings of fact and conclusions of
law, and, again, in his objections to the Magistrate Judge’s
report. App. 422–423, 432–433; App. to Pet. for Cert. A51–
A52; supra, at 687, 689. Banks contended, unsuccessfully,
that evidence substantiating the Cook Brady claim had been
aired before the Magistrate Judge; therefore the claim
should have been treated as if raised in the pleadings, as
Federal Rule of Civil Procedure 15(b) instructs. See App.
to Pet. for Cert. A51–A52; supra, at 687, n. 8 (setting out
text of Rule 15(b)). The Fifth Circuit stated its position on
this point somewhat obliquely, but appears to have viewed
Rule 15(b) as inapplicable in habeas proceedings; the State
now concedes, however, that the question whether Rule 15(b)
extends to habeas proceedings is one “jurists of reason would

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find . . . debatable.” Compare App. to Pet. for Cert. A52
(quoting Slack v. McDaniel, 529 U. S. 473, 484 (2000)), with
Tr. of Oral Arg. 45–46. We conclude that a certificate of
appealability should have issued.
We have twice before referenced Rule 15(b)’s application
in federal habeas proceedings. In Harris v. Nelson, 394
U. S. 286, 294, n. 5 (1969), we noted that Rule 15(b)’s use
in habeas proceedings is “noncontroversial.” In Withrow v.
Williams, 507 U. S. 680, 696, and n. 7 (1993), we similarly
assumed Rule 15(b)’s application to habeas petitions. There,
however, the District Court had granted a writ of habeas
corpus on a claim neither pleaded, considered at “an eviden-
tiary hearing,” nor “even argu[ed]” by the parties. Id., at
695. Given those circumstances, we held that there had
been no trial of the claim by implied consent; the respondent
warden, we observed, “was manifestly prejudiced by the Dis-
trict Court’s failure to afford her an opportunity to present
evidence bearing on th[e] claim’s resolution.” Id., at 696.
Here, in contrast, the issue of the undisclosed Cook interro-
gation transcript was indeed aired before the Magistrate
Judge, and the transcript itself was admitted into evidence
without objection. See supra, at 685.19
The Court of Appeals found no authority for equating “an
evidentiary hearing . . . with a trial” for Rule 15(b) purposes.
App. to Pet. for Cert. A52. We see no reason why an evi-
dentiary hearing should not qualify so long as the respondent
gave “any sort of consent” and had a full and fair “opportu-
19 See Federal Evidentiary Hearing 56–73. Examining one of Banks’s
prosecutors, counsel for Banks twice asked if Cook had been “instructed
. . . on how to testify.” Id., at 56. See also id., at 63–64 (“Texarkana law
enforcement did not instruct Mr. Cook how to testify in this case. Is that
your testimony today?”). To show that Cook had been coached, Banks’s
counsel called attention to discrepancies between portions of the Septem-
ber 1980 transcript and Cook’s trial testimony. Id., at 65–68. Conclud-
ing his examination, Banks’s counsel emphasized the prosecution’s duty to
disclose the September 1980 transcript once Cook, while on the stand,
stated that he had not been coached. Id., at 73–74; App. 59; supra, at 677.

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nity to present evidence bearing on th[e] claim’s resolution.”
Withrow, 507 U. S., at 696. Nor do we find convincing the
Fifth Circuit’s view that applying Rule 15(b) in habeas pro-
ceedings would undermine the State’s exhaustion and proce-
dural default defenses. Ibid. Under pre-AEDPA law,
there was no inconsistency between Rule 15(b) and those
defenses. That is doubtless why this Court’s pre-AEDPA
cases assumed Rule 15(b)’s application in habeas proceed-
ings. See ibid.; Harris, 394 U. S., at 294, n. 5.20 We note in
this regard that, while AEDPA forbids a finding that exhaus-
tion has been waived unless the State expressly waives the
requirement, 28 U. S. C. § 2254(b)(3), under pre-AEDPA law,
exhaustion and procedural default defenses could be waived
based on the State’s litigation conduct. See Gray v. Nether-
land, 518 U. S. 152, 166 (1996) (failure to raise procedural
default in federal habeas court means the defense is lost);
Granberry v. Greer, 481 U. S. 129, 135 (1987) (“if a full trial
has been held in the district court and it is evident that a
miscarriage of justice has occurred, it may . . . be appropriate
for the court of appeals to hold that the nonexhaustion de-
fense has been waived”).
To obtain a certificate of appealability, a prisoner must
“demonstrat[e] that jurists of reason could disagree with the
district court’s resolution of his constitutional claims or that
jurists could conclude the issues presented are adequate to
deserve encouragement to proceed further.” Miller-El v.
Cockrell, 537 U. S. 322, 327 (2003). At least as to the appli-
cation of Rule 15(b), this case surely fits that description. A
certificate of appealability, therefore, should have issued.
* * *
For the reasons stated, the judgment of the United States
Court of Appeals for the Fifth Circuit is reversed, and the
20 Banks’s case provides no occasion to consider Rule 15(b)’s application
under the AEDPA regime.

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706 BANKS v. DRETKE
Opinion of Thomas, J.
case is remanded for further proceedings consistent with
this opinion.
It is so ordered.
Justice Thomas, with whom Justice Scalia joins, con-
curring in part and dissenting in part.
I join Part III of the Court’s opinion, and respectfully dis-
sent from Part II, which holds that Banks’ claim under
Brady v. Maryland, 373 U. S. 83 (1963), relating to the non-
disclosure of evidence that Farr accepted money from a po-
lice officer during the course of the investigation, warrants
habeas relief. Although I find it to be a very close question,
I cannot conclude that the nondisclosure of Farr’s informant
status was prejudicial under Kyles v. Whitley, 514 U. S. 419
(1995), and Brady.1
To demonstrate prejudice, Banks must show that “the fa-
vorable evidence could reasonably be taken to put the whole
case in such a different light as to undermine confidence in
the verdict.” Kyles, supra, at 435. The undisclosed mate-
rial consisted of evidence that “Willie Huff asked [Farr] to
help him find [Banks’] gun,” and that Huff “gave [Farr] about
$200.00 for helping him.” App. 442 (Farr Declaration).
Banks contends that if Farr’s receipt of $200 from Huff had
been revealed to the defense, there would have been a “rea-
sonable probability,” Kyles, supra, at 434, that the jury
would not have found “beyond a reasonable doubt that there
1 I do not address the possible application of the standard enunciated in
Giglio v. United States, 405 U. S. 150 (1972), since I agree with the Court
of Appeals that the issue was not properly raised below, and since address-
ing this issue would go beyond the question on which certiorari was
granted. See Brief for Petitioner (i) (stating the question presented as
whether “the Fifth Circuit commit[ted] legal error in rejecting Banks’
Brady claim—that the prosecution suppressed material witness impeach-
ment evidence that prejudiced him in the penalty phase of his trial—on
the grounds that: . . . the suppressed evidence was immaterial to Banks’
death sentence”).

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707 Cite as: 540 U. S. 668 (2004)
Opinion of Thomas, J.
[was] a probability that the defendant, Delma Banks, Jr.,
would commit criminal acts of violence that would constitute
a continuing threat to society.” App. 143 (the second spe-
cial issue presented to the jury) (internal quotation marks
omitted).
I do not believe that there is a reasonable probability that
the jury would have altered its finding. The jury was pre-
sented with the facts of a horrible crime. Banks, after
meeting the victim, Richard Whitehead, a 16-year-old boy
who had the misfortune of owning a car that Banks wanted,
decided “to kill the person for the hell of it” and take his car.
Banks v. State, 643 S. W. 2d 129, 131 (Tex. Crim. App. 1982)
(en banc), cert. denied, 464 U. S. 904 (1983). Banks pro-
ceeded to shoot Whitehead three times, twice in the head
and once in the upper back. Banks fired one of the shots
only 18 to 24 inches away from Whitehead. The jury was
thus presented with evidence showing that Banks, appar-
ently on a whim, executed Whitehead simply to get his car.
The jury was also presented with evidence, in the form of
Banks’ own testimony, that he was willing to abet another
individual in obtaining a gun, with the full knowledge that
this gun would aid future armed robberies. The colloquy
between a prosecuting attorney and Banks makes it clear
what Banks thought he was doing:
“Q: You were going to supply him [Farr] your gun so
he could do armed robberies?
“A: No, not supply him my gun. A gun.
“Q: In other words you didn’t care if it was yours or
whose, but you were going to be the man who got the
gun to do armed robberies. Is that correct?
“A: He was going to do it.
“Q: I understand, but you were going to supply him
the means and possible death weapon in an armed rob-
bery case. Is that correct?
“A: Yes.” App. 137 (cross-examination of Banks).

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708 BANKS v. DRETKE
Opinion of Thomas, J.
Accordingly, the jury was also presented with Banks’ will-
ingness to assist others in committing deadly crimes. In-
deed, the prosecution referenced this very fact at one point
during its closing argument in its attempt to convince the
jury that Banks posed a threat to commit violent acts in
the future:
“The testimony of Vetrano Jefferson and Robert Farr is
of the utmost significance. Vetrano brought before you
the scar on his face, put there by Delma Banks. . . . He
also corroborates or supports the testimony of Robert
Farr. You don’t have to believe just Robert in order to
find that Delma went to Dallas to get a pistol so that
somebody could do some robberies. Marcus Jefferson
told you that, too.” Id., at 146 (emphasis added).2
The jury also heard testimony that Banks had violently
pistol-whipped and threatened to kill his brother-in-law one
week before the murder. Banks now claims that this evi-
dence should be discounted because his trial counsel failed
to uncover that the brother-in-law was “responsible for the
fight.” Brief for Petitioner 33. But even if it is appropriate
to mix-and-match the prejudice analysis of the Brady claim
and the claim under Strickland v. Washington, 466 U. S. 668
(1984) (rather than to evaluate them independently, as dis-
tinct potential constitutional violations), Banks’ response
was vastly disproportional to his brother-in-law’s actions.
In sum, the jury knew that Banks had murdered a 16-
year-old on a whim, had violently attacked and threatened a
relative shortly before the murder, and was willing to assist
another individual in committing armed robberies by provid-
ing the “means and possible death weapon” for these robber-
ies. App. 137. Even if the jury were to discredit entirely
2 Admittedly, the prosecution used more of its closing argument trying
to convince the jury to believe Farr’s testimony that Banks himself was
planning more robberies. See ante, at 699–700, n. 18. This fact is one of
the reasons I find the materiality question to be a close one.

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709 Cite as: 540 U. S. 668 (2004)
Opinion of Thomas, J.
Farr’s testimony that Banks was planning more robberies,3
in all likelihood the jury still would have found “beyond
a reasonable doubt” that there “[was] a probability that
[Banks] would commit criminal acts of violence that would
constitute a continuing threat to society.” Id., at 143 (inter-
nal quotation marks omitted). The randomness and wanton-
ness of the murder would perhaps, standing alone, mandate
such a finding. Accordingly, I cannot find that the nondisclo-
sure of the evidence was prejudicial.
Because Banks cannot show prejudice, I do not resolve
whether he has cause to excuse his failure to present his Farr
Brady evidence in state court, Keeney v. Tamayo-Reyes, 504
U. S. 1, 11–12 (1992). But there are reasons to doubt the
Court’s conclusion that Banks can show cause. For instance,
the Court concludes that “[t]his case is congruent with
Strickler [v. Greene, 527 U. S. 263 (1999)],” ante, at 693, rely-
ing in part on the State’s general denial of all of Banks’ fac-
tual allegations contained in his January 1992 state habeas
application. But, in the relevant state postconviction pro-
ceeding in Strickler, the State alleged that the petitioner had
already received “ ‘everything known to the government,’ ”
a statement that federal habeas proceedings established was
clearly not true. 527 U. S., at 289 (emphasis added). In the
instant case, the particular allegation raised in Banks’ state
habeas application and denied by the State was that “the
3 It is quite possible that the jury already discredited this aspect of
Farr’s testimony. The jury knew, from the testimony of witnesses James
Kelley and Officer Gary Owen, that Farr was generally dishonest, as it
heard how he had lied about getting into an altercation with a doctor over
false prescriptions, and had lied about his status as an informant for an
Arkansas officer in other cases. The Court suggests that the witnesses
providing this information were themselves “impeached.” Ante, at 702.
At best, though, they were only slightly impeached. The prosecution
merely intimated that Owen was slanting his testimony in the hopes of
being hired by the defense counsel’s private investigator, App. 131, and
that Kelley was doing the same as he was a “friend of [Banks’] family,”
id., at 141.

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710 BANKS v. DRETKE
Opinion of Thomas, J.
prosecution knowingly failed to turn over exculpatory evi-
dence as required by Brady v. Maryland, 373 U. S. 83
(1963).” App. 180 (emphasis added). The State, then, could
have been denying only that the prosecution knowingly
failed to turn over the evidence (there is, incidentally, very
little evidence in the record tending to show that any prose-
cutor had actual knowledge of Huff ’s payment to Farr). Or,
the State could have been denying only that it had failed to
turn over evidence in violation of Brady, i. e., that any evi-
dence the prosecution did not turn over was not material (a
position advanced by the State throughout the federal ha-
beas process), see Strickler, supra, at 281 (“[S]trictly speak-
ing, there is never a real ‘Brady violation’ unless the nondis-
closure was so serious that there is a reasonable probability
that the suppressed evidence would have produced a differ-
ent verdict”). Either way, Strickler does not clearly con-
trol, and the Court’s reliance on it is less than compelling.
Because of the Court’s disposition of Banks’ Farr Brady
claim, it does not address his claim of ineffective assistance
of counsel, concluding that “any relief he could obtain on that
claim would be cumulative.” Ante, at 689, n. 10. As I
would affirm the Court of Appeals on the Farr Brady claim,
I briefly discuss this ineffective-assistance claim. Although
I find the Farr Brady claim a close call, I do not find this to
be so as to the ineffective-assistance claim. Banks comes
nowhere close to satisfying the prejudice prong of Strick-
land v. Washington, supra. The conclusory and uncorrobo-
rated claims of some level of physical abuse, the allegations
that a bad skin condition negatively affected his childhood
development, the evidence that he was a slow learner and
possessed a willingness to please others, and the claim that
Banks’ brother-in-law was responsible for his own pistol-
whipping and receipt of a death threat, are so unpersuasive
that there is no reasonable probability that the jury would
have come to the opposite conclusion with respect to the fu-

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711 Cite as: 540 U. S. 668 (2004)
Opinion of Thomas, J.
ture dangerousness special issue, even if presented with
this evidence.
I therefore conclude that the Court of Appeals did not err
when it denied relief to Banks based on his Farr Brady claim
and his Strickland claim. I would reverse the Court of Ap-
peals only insofar as it did not grant a certificate of appeal-
ability on the Cook Brady claim.