                 FOR PUBLICATION
 UNITED STATES COURT OF APPEALS
      FOR THE NINTH CIRCUIT

ANTON E. BARKER,                         No. 04-35911
             Petitioner-Appellant,
               v.                          D.C. No.
                                         CV-03-03134-EFS
GARY FLEMING,
                                            OPINION
            Respondent-Appellee.
                                     
       Appeal from the United States District Court
         for the Eastern District of Washington
        Edward F. Shea, District Judge, Presiding

                  Argued and Submitted
            June 8, 2005—Seattle, Washington

                 Filed September 8, 2005

     Before: Procter Hug, Jr., David R. Thompson, and
          M. Margaret McKeown, Circuit Judges.

               Opinion by Judge McKeown




                          12591
                     BARKER v. FLEMING               12595


                       COUNSEL

Professor Jacqueline McMurtrie, Lindsay L. Halm, Law Stu-
dent, & Lesli S. Wood, Law Student, Innocence Project
Northwest Clinic, University of Washington School of Law,
Seattle, Washington, for the appellant.

Gregory J. Rosen, Assistant Attorney General, Attorney Gen-
eral’s Office, Criminal Justice Division, Olympia, Washing-
ton, for the appellee.
12596                     BARKER v. FLEMING
                              OPINION

McKEOWN, Circuit Judge:

   This petition for a writ of habeas corpus presents the ques-
tion whether the prosecution in a robbery case suppressed evi-
dence in violation of Brady v. Maryland, 373 U.S. 83 (1963).
In analyzing this issue, the Washington Supreme Court failed
to consider the cumulative effect of the undisclosed evidence
and thus its decision was contrary to clearly established
Supreme Court precedent. 28 U.S.C. § 2254(d)(1) (permitting
grants of habeas corpus where the state court issued a decision
that was contrary to, or an unreasonable application of, clearly
established federal law); Kyles v. Whitley, 514 U.S. 419, 436-
37 & n.10 (1995) (holding that the State’s disclosure obliga-
tion under Brady turns on the cumulative effect of the with-
held evidence, not an item by item analysis). Even so, we
conclude on de novo review that the witness who would have
been impeached by the suppressed evidence was so severely
discredited and not so critical to the prosecution’s case that
there is no reasonable probability that the withheld evidence
would have affected the outcome. Accordingly, we affirm the
district court’s denial of the petition.1

            FACTUAL AND PROCEDURAL BACKGROUND

  Sheniece Brown was working as a clerk at Payless Shoe-
Source when a man, who had a handkerchief covering his
  1
    Barker also presents an uncertified issue with respect to admission of
expert testimony on eyewitness identification. We decline to expand the
Certificate of Appealability (“COA”) to reach this question because
Barker has failed to make a “substantial showing of the denial of a consti-
tutional right.” 28 U.S.C. § 2253(c)(2). Despite the fundamental right of
a defendant to offer the testimony of witnesses, Chambers v. Mississippi,
410 U.S. 284, 302 (1973), the exclusion of expert testimony on eyewitness
identification does not violate that right. See Jordan v. Ducharme, 983
F.2d 933, 939 (9th Cir. 1993) (“There is no federal authority that [expert
testimony on eyewitness identification] must be allowed.”)
                       BARKER v. FLEMING                   12597
nose and mouth and appeared to be bleeding, entered the
store. As Brown approached him, she realized that he was not
injured but instead had red marks drawn with makeup on the
backs of his hands and on the sides of his face. The man told
Brown that it was a holdup and forced her to open the cash
register and till by shoving a hard object into her back that felt
like a gun. As the man took the cash from the till, she stood
to his right side for a couple of minutes trying to memorize
his profile. She testified, “I stood back on the right side of the
register . . . about four feet away . . . and I was trying to mem-
orize his profile. And so he brought the handkerchief down
from his face . . . .” She saw that his face was covered with
brown foundation and that there was a blue circle painted on
one cheek along with some red marks on both sides of his
face.

   Brown initially provided a general description of the assail-
ant, but without a name or identification of a specific individ-
ual, the police had no leads. The so-called “clown robber”
became the subject of media headlines. A few days later,
Brown talked about the robbery with two of her co-workers,
Maria Diaz and Amber Trainer. Based on her description,
Trainer and Diaz said they thought the robber was a man who
frequently visited the store but never bought anything. Trainer
told Brown what the suspicious customer looked like, noting
that he had several tattoos. Trainer and Brown put their heads
together and concluded that the robber’s makeup probably
was covering the tattoos.

  After her discussion with her colleagues, Brown called the
police and told a detective that the robber looked a lot like a
man who often came to the store. Although Brown had never
seen the suspicious customer before, she described him and
emphasized that he had tattoos on his hands and neck that she
thought were covered by the makeup. Upon hearing her
description, the detective said, “I think I know who that is.
This guy’s been in jail before.”
12598                  BARKER v. FLEMING
   Based on the additional information about the suspicious
customer, the police pursued the case. Brown identified
Barker from a photo montage of six men. When she first saw
Barker’s picture, it “took [her] breath away because . . . that’s
him.” Brown was confident in her identification because of
the suspect’s “medium-sized nose, his cheekbones, and he had
a moustache on the picture in this montage, even though he
didn’t that night, but I knew that was him.” After she identi-
fied Barker, she was shown a booking photograph and a pro-
file shot of Barker that made her even more certain that the
identification was correct.

   Barker was first tried in June 1999. Brown’s identification
was the centerpiece of the prosecution’s case because the
store security camera failed to produce a usable photograph of
the robber, and the police failed to obtain fingerprints. Barker
represented himself pro se and the trial ended in a hung jury.

   Between the first and second trials, the prosecution
obtained new evidence from a jailhouse snitch, Raul Abundiz.
At the second trial, Abundiz testified that Barker confessed to
committing the crime when the two of them were near a motel
in early April, 1999. Abundiz also testified that he and Barker
talked on June 14, 1999, around 10 a.m. when they were wait-
ing for their respective court appearances in a holding cell.

   Abundiz’s testimony, though, was not without warts. He
was impeached in all manner of ways, from admitting to
lying, to confessing to prior convictions, to acknowledging
that he was testifying only because he had received a deal
from the State. The image of Abundiz presented to the jury
was that of a chronic drug user willing to do anything to get
out of jail and anxious to capitalize on his knowledge about
Barker: The details of Abundiz’s deal were fully disclosed
and he admitted that he was testifying only because of the
agreement. The jury also heard testimony that Barker had
threatened to kill Abundiz and that Abundiz was looking for
Barker “to do some harm to him” with a pistol.
                          BARKER v. FLEMING                        12599
   The jury returned a conviction for second degree robbery,
and Barker was sentenced to life without parole. He appealed
to the Washington Court of Appeals, which affirmed his con-
viction. See State v. Barker, 14 P.3d 863 (Wash. Ct. App.
2000). The Washington Supreme Court denied review.

   After he exhausted his direct appeals, Barker pursued relief
via a Personal Restraint Petition (“PRP”), Washington State’s
mechanism for collateral challenges. An independent investi-
gation revealed several pieces of evidence that had not been
disclosed to the defense before trial. This evidence forms the
basis of Barker’s Brady claim.

  The first category of undisclosed evidence consists of four
misdemeanor convictions of Abundiz that occurred within the
year preceding the trial:

      1) June 15, 1999—conviction for obstructing the
      duties of a police officer and trespassing based on an
      incident that involved Abundiz lying about his iden-
      tity to the police.

      2) March 30, 1999—shoplifting conviction based on
      an incident that also involved possession of drug par-
      aphernalia.

      3) March 19, 1999—shoplifting conviction.

      4) August 18, 1998—false reporting conviction
      based on an incident that involved providing false
      information to the police.

All four of these crimes are considered crimes of dishonesty
in Washington.2
  2
    The two convictions for false reporting involve dishonesty. The other
two were for shoplifting, which is a crime of dishonesty in Washington.
See State v. Ray, 806 P.2d 1220, 1228 (Wash. 1991) (en banc) (“[C]rimes
of theft involve dishonesty and are per se admissible for impeachment pur-
poses.”).
12600                 BARKER v. FLEMING
  The second group of undisclosed evidence revolves around
a charge for residential burglary that Abundiz faced in June
1999, at the same time that Barker’s first trial occurred.
Barker identifies three pieces of evidence:

    1) Documentation that a court found probable cause
    to believe that Abundiz committed residential bur-
    glary. Barker points to a June 14, 1999, Superior
    Court of Yakima County Order finding probable
    cause and setting bail at $20,000 and to a transcript
    of Abundiz’s probable cause hearing.

    2) A police report documenting a June 14, 1999,
    meeting between the same detective with whom
    Brown spoke and Abundiz during which they dis-
    cussed the residential burglary charge. The report
    states that the prosecutor’s office concluded there
    was not enough evidence to prove the case. The
    report does not mention Abundiz’s robbery of a JC
    Penny store, which occurred a few days earlier, or
    his conversation with Barker, which allegedly
    occurred that morning. The report makes no mention
    that Abundiz had information about the robbery of
    Payless.

    3) A June 16, 1999, order releasing Abundiz and
    stating that the State decided not to charge him with
    residential burglary. The order was signed by a dep-
    uty prosecutor “for Ken Ramm,” who was the prose-
    cutor in Barker’s first trial.

   Barker first raised his claim that the prosecution withheld
the above evidence in the PRP he filed in the Washington
Court of Appeals, which dismissed his petition. The Washing-
ton Supreme Court, through its Commissioner, denied discre-
tionary review in a thorough opinion. The court itself adopted
the Commissioner’s decision by denying a motion to modify
the ruling. The Washington Supreme Court held that Barker
                          BARKER v. FLEMING                         12601
failed to show that suppression of the evidence caused him
prejudice because Abundiz’s credibility was so thoroughly
destroyed that the withheld convictions would not have mat-
tered. The court went on to note that the alleged residential
burglary deal was speculative and that any evidence indicat-
ing a deal was cumulative because the jury already knew
Abundiz received benefits for his testimony.

   Barker filed a federal petition for a writ of habeas corpus
in the district court, which reviewed the Washington Court of
Appeals’ decision and denied relief.

                              DISCUSSION

I.       STANDARDS AND SCOPE OF REVIEW

   In a habeas corpus petition, two standards of review are at
play. See, e.g., Lambert v. Blodgett, 393 F.3d 943, 964-65
(9th Cir. 2004). The first standard is the straightforward de
novo standard we employ to evaluate the district court’s deci-
sion to deny the petition. E.g., Beardslee v. Woodford, 358
F.3d 560, 568 (9th Cir. 2004) (as amended). The standard that
governs review of the state court’s decision is established by
the Antiterrorism and Effective Death Penalty Act of 1996
(“AEDPA”), which prohibits a federal court from granting
habeas relief “with respect to any claim that was adjudicated
on the merits in State court proceedings unless the adjudica-
tion of the claim resulted in a decision that was contrary to,
or involved an unreasonable application of, clearly established
Federal law, as determined by the Supreme Court of the
United States.” 28 U.S.C. § 2254(d)(1).

   Before we can apply AEDPA’s standards, we must identify
the state court decision that is appropriate for our review.
When more than one state court has adjudicated a claim, we
analyze the last reasoned decision. See Ylst v. Nunnemaker,
501 U.S. 797, 803-04 (1991);3 Avila v. Galaza, 297 F.3d 911,
     3
   Although the Court in Ylst was concerned with determining whether
the state court had lifted a procedural bar to a claim by reaching the mer-
12602                      BARKER v. FLEMING
918 (9th Cir. 2002) (“In determining whether a state court
decision is contrary to federal law, we look to the state’s last
reasoned decision.”). Here, the last reasoned state decision is
the Washington Supreme Court’s denial of discretionary
review of the PRP dismissal. The Court, through its Commis-
sioner, issued a seven-page order that explained in detail why
review was denied and specifically examined the substance of
Barker’s Brady claim.

   Determining that the Supreme Court’s decision is the last
reasoned decision does not resolve the question whether it is
the proper decision to review. We must still decide whether
it is “an adjudication on the merits” because 28 U.S.C.
§ 2254(d) applies only to those claims that have been adjudi-
cated on the merits. 28 U.S.C. § 2254(d). The requirement of
an adjudication on the merits does not mandate a hearing or
other judicial process beyond rendering a decision; rather it
means that the court must finally resolve the rights of the par-
ties on the substance of the claim, rather than on the basis of
a procedural or other rule precluding state review of the mer-
its. Lambert, 393 F.3d at 969. Under this definition of “adju-
dication on the merits,” in Lambert we concluded that a
Washington Supreme Court Ruling Denying Review, the
same kind of decision at issue here, was an adjudication on
the merits. Id. at 970 & n.17 (stating that the Washington
Supreme Court reached the merits of the petitioner’s claim
and deciding to review primarily the Supreme Court’s ruling).

  Lambert, then, settles that a Washington Supreme Court
order denying review of a PRP, when it is reasoned and dis-

its, the doctrine that a federal habeas court reviews the last reasoned state
decision has been extended beyond the context of procedural default. See,
e.g., Lambert, 393 F.3d at 970 n.17 (looking to last reasoned decision in
a case that did not involve procedural default); Bailey v. Rae, 339 F.3d
1107, 1112-13 (9th Cir. 2003) (explaining that, where procedural default
is not at issue, identifying the last explained decision is relevant only for
purposes of applying AEDPA).
                            BARKER v. FLEMING                          12603
cusses the merits, is an “adjudication on the merits” that may
be reviewed by federal courts under AEDPA. Even before
Lambert fleshed out the meaning of “adjudication on the mer-
its” under AEDPA we reviewed Washington Supreme Court
denials of review. See Riley v. Payne, 352 F.3d 1313, 1316,
1322 (9th Cir. 2003).4 Thus, we travel well charted territory
when we consider the Washington Supreme Court’s order as
an adjudication on the merits that we may review under
AEDPA.

   The State urges us to review the decisions of the Washing-
ton Court of Appeals and Supreme Court together as a collec-
tive whole. This argument relies both on language in 28
U.S.C. § 2254(d) referring to “state court proceedings,” plu-
ral, and on Ninth Circuit cases that have reviewed multiple
state court decisions together. Neither source persuades us
that collective review is appropriate in this case.

   The text of 28 U.S.C. § 2254(d)(1) is at best ambiguous as
to whether we may review multiple state court judgments at
once. Habeas relief, under § 2254(d)(1), is prohibited with
respect to “any claim that was adjudicated on the merits in
State court proceedings unless the adjudication of the claim
resulted in a decision that was contrary to, or involved an
unreasonable application of, clearly established Federal law,
as determined by the Supreme Court of the United States.”
Obviously, the provision employs the plural “State court pro-
ceedings,” which could indicate that Congress intended all
state proceedings to be considered as a whole. Equally likely,
however, is that “proceedings” is used here in a generic sense
and not as a reference to multiple final adjudications. Signifi-
  4
    In one instance, the Riley opinion refers to the Washington Supreme
Court decision as “affirm[ing]” the Court of Appeals’ denial of the PRP,
rather than as denying review of the Court of Appeals’ decision. 352 F.3d
at 1316. Our review of the Washington Supreme Court decision in Riley
confirms that, like the ruling in this case, it is an order denying discretion-
ary review.
12604                 BARKER v. FLEMING
cantly, the text refers to “a decision that was contrary to, or
involved an unreasonable application of, clearly established
Federal law.” Id. (emphasis added). The reference to a single
decision underscores that Congress meant federal courts to
review only one final state court decision.

   Most telling, the Supreme Court describes AEDPA review
as applying to a single state court decision, not to some amal-
gamation of multiple state court decisions. In Williams v. Tay-
lor, 529 U.S. 362 (2000), the landmark decision explaining
the meaning of the “contrary to” and “unreasonable applica-
tion of” prongs of AEDPA, Justice O’Connor, writing for the
Court, viewed these prongs of the statute as applying to a sin-
gle state decision. She repeatedly and consistently used singu-
lar references to identify the state court adjudication under
review. See, e.g., id. at 405 (“A state-court decision will cer-
tainly be contrary to our clearly established federal prece-
dent”; “If a state court were to reject”; “the state court’s
decision must be substantially different”).

   The Court’s analysis of the state court proceedings in Wil-
liams confirms our conclusion that AEDPA generally requires
federal courts to review one state decision. In Williams, the
Virginia Supreme Court applied a standard that was contrary
to federal law while the trial court applied the correct stan-
dard. Id. at 395. The Supreme Court did not aggregate the two
state court decisions or engage in “collective review.” Instead,
it reviewed only the Virginia Supreme Court decision and
held that it was contrary to federal law. Id. at 397-99. Thus,
even when one state court adhered to federal law, if the last
court to review the claim erred, the federal court should
review the last decision in isolation and not in combination
with decisions by other state courts.

   We are cognizant that some of our cases discuss two state
court decisions simultaneously. See Lambert, 393 F.3d at 970
n.17 (reviewing the state supreme court’s decision but stating
that “because the supreme court largely adopted the reasoning
                       BARKER v. FLEMING                   12605
of the court of appeals, we also discuss the court of appeals’
decision”); Lewis v. Lewis, 321 F.3d 824, 829 (9th Cir. 2003)
(“Because [the state appellate court’s] decision affirmed the
trial court and adopted one of the reasons cited by the trial
court, . . . our analysis will necessarily include discussion of
the trial court’s decision as well.”). In each of these cases, the
last reasoned decision adopted or substantially incorporated
the reasoning from a previous decision and, as a result, it was
reasonable for the reviewing court to look at both decisions to
fully ascertain the reasoning of the last decision. Here, the
Washington Supreme Court did not adopt the Court of
Appeals’ decision, although agreeing with its reasoning.
Rather, the Commissioner reviewed the record independently
and authored an order that reflected his own reasoning. Thus,
we review the Supreme Court Ruling Denying Review with-
out considering the decision of the Washington Court of
Appeals.

II.   “CONTRARY TO CLEARLY ESTABLISHED FEDERAL LAW”

   [1] Supreme Court holdings at the time of the state court’s
last reasoned decision are the source of clearly established
Federal law for the purposes of AEDPA. Williams, 529 U.S.
at 412; Clark v. Murphy, 331 F.3d 1062, 1069 (9th Cir. 2003).
At the time the Washington Supreme Court denied review of
Barker’s PRP, the components of a Brady claim were clearly
established by Supreme Court law—a defendant must show
that 1) the prosecution suppressed evidence that 2) was
favorable to the accused and 3) was material. Strickler v.
Greene, 527 U.S. 263, 281-82 (1999) (summarizing the ele-
ments of a Brady claim). The Court first defined materiality
in United States v. Bagley, 473 U.S. 667, 682 (1985), holding
that evidence is material “if there is a reasonable probability
that, had the evidence been disclosed to the defense, the result
of the proceeding would have been different.”

   [2] Crucial to this case is the Supreme Court’s requirement
that the materiality of the withheld evidence be analyzed
12606                 BARKER v. FLEMING
cumulatively: One “aspect of Bagley materiality to be stressed
here is its definition in terms of suppressed evidence consid-
ered collectively, not item by item.” Kyles, 514 U.S. at 436.
The Court specifically explained that courts should “evaluate
the tendency and force of the undisclosed evidence item by
item; there is no other way. We evaluate its cumulative effect
for purposes of materiality separately and at the end of the
discussion.” Id. at 436 n.10.

   [3] Despite the clarity of the Supreme Court’s directive that
a materiality analysis include an assessment of the cumulative
effect of undisclosed evidence, the Washington Supreme
Court did not conduct such an analysis. Instead, the court sep-
arately analyzed the withheld convictions and the evidence
related to Abundiz’s residential burglary charge on a piece-
meal basis and then ended its analysis. Examining the effect
of the withheld evidence group by group, as the court did
there, is only the first half of the analysis. Because the Wash-
ington Supreme Court failed to complete the second half of
the equation, which requires evaluation of the cumulative
effect of all the withheld evidence “separately and at the end
of the discussion,” id., its decision was contrary to clearly
established Federal law as set forth in Kyles. See Castleberry
v. Brigano, 349 F.3d 286, 291-92 (6th Cir. 2003) (holding that
a state court decision that failed to analyze withheld evidence
cumulatively was contrary to Kyles).

   Barker offers an alternate argument for why the decision is
contrary to Federal law. He contends that the Washington
Supreme Court’s “actual and substantial prejudice” standard
imposed a more stringent prejudice requirement than Federal
law because the prejudice inquiry under Brady requires only
a showing that “there is a reasonable probability that, had the
evidence been disclosed to the defense, the result of the pro-
ceeding would have been different.” Bagley, 473 U.S. at 682;
see also Strickler, 527 U.S. at 280. The showing of actual and
substantial prejudice, Barker contends, heaps an extra burden
on petitioners that contradicts Federal law.
                           BARKER v. FLEMING                          12607
   We need not reach Barker’s argument, having already con-
cluded that the decision was contrary to Federal law, but we
take this opportunity to observe that the interplay of the
Washington PRP “actual and substantial prejudice” standard
and the Brady materiality standard is not without confusion.
It is unclear whether the PRP standard, as used here, governs
a threshold examination that determines whether a petitioner
may raise his claim, see, e.g., In re Cook, 792 P.2d 506, 510-
11 (Wash. 1990) (en banc), or whether it is the ultimate show-
ing required for relief, see id. at 512. The difference matters
for federal habeas review because if the standard is a thresh-
old obstacle to state court review, it would not conflict with
the Brady materiality standard. In that event, the petitioner
simply would fail to gain access to Washington’s post-
conviction review. If it is a substantive standard imposed in
addition to the prejudice showing required under Brady and
its progeny, it appears to impose a higher burden than is
required to establish prejudice under Brady.5

III.   ANALYSIS OF THE BRADY CLAIM

   [4] Because the state court did not conduct the proper anal-
ysis, AEDPA’s restrictions on our review do not apply. See,
e.g., Cooperwood v. Cambra, 245 F.3d 1042, 1046 (9th Cir.
2001); Wade v. Terhune, 202 F.3d 1190, 1195 (9th Cir. 2000).
   5
     In practice, Washington courts often avoid the potential conflict
between the “actual and substantial prejudice” standard, which applies in
all PRPs raising constitutional claims for the first time, and other federal
standards that incorporate prejudice in one of two ways. The courts may
waive the burden of establishing actual and substantial prejudice when an
error gives rise to a conclusive presumption of prejudice. See In re
Orange, 100 P.3d 291, 295 (Wash. 2004) (en banc); In re St. Pierre, 823
P.2d 492, 496 (Wash. 1992) (en banc) (errors that are never harmless on
direct appeal may be per se prejudicial in a collateral attack). Or the courts
may equate the “actual and substantial prejudice” standard with the preju-
dice showing incorporated in the federal test. See, e.g., In re Dalluge, 100
P.3d 279, 287 (Wash. 2004) (en banc) (granting relief upon a finding of
prejudice under the federal ineffective assistance of counsel prejudice
standard).
12608                  BARKER v. FLEMING
Accordingly, we review Barker’s Brady claim de novo apply-
ing the correct analysis. See Cooper-Smith v. Palmateer, 397
F.3d 1236, 1243 (9th Cir. 2005) (as amended); Cooperwood,
245 F.3d at 1046.

   [5] We begin by returning to Brady itself, which estab-
lished 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 punishment,
irrespective of the good faith or bad faith of the prosecution.”
373 U.S. at 87. Barker readily establishes the first prong of his
Brady claim, that the evidence would have been favorable to
him. It is well settled that evidence impeaching the testimony
of a government witness falls within the Brady rule, see, e.g.,
Singh v. Prunty, 142 F.3d 1157, 1161 (9th Cir. 1998), and the
government does not dispute that the four misdemeanor con-
victions were relevant to Abundiz’s credibility. Nor is there
a serious argument that evidence of a deal with Abundiz and
of contact between Barker and Abundiz would not have been
useful impeachment evidence. See, e.g., Bagley, 473 U.S. at
683 (evidence indicating that witness received inducement
from prosecution to testify constituted evidence favorable to
the accused); Benn v. Lambert, 283 F.3d 1040, 1057 (9th Cir.
2002) (explaining that prosecution-provided benefits are
Brady material because they indicate that a witness may have
reasons for testifying other than altruism). Barker’s claim that
the State agreed to drop the residential burglary charge
against Abundiz in exchange for his testimony is speculative,
but at the same time, it takes little imagination to see how a
competent attorney could have implied that such a deal
existed. It takes even less imagination to see how evidence
calling into question whether Barker and Abundiz talked on
June 14 would have helped Barker impeach Abundiz.

   [6] The second prong of the Brady claim, that the prosecu-
tion failed to disclose evidence, is subject to some dispute.
The Washington Supreme Court was unconvinced that the
prosecution had access to all the information that Barker
                           BARKER v. FLEMING                         12609
argues was suppressed,6 but we need not explore the particu-
lars of this issue because Barker’s claim is defeated by the
lack of materiality of the allegedly withheld evidence. Signifi-
cantly, “[w]e do not . . . automatically require a new trial
whenever a combing of the prosecutors’ files after the trial
has disclosed evidence possibly useful to the defense but not
likely to have changed the verdict . . . A finding of materiality
of the evidence is required . . . .” Bagley, 473 U.S. at 677
(internal quotations and citation omitted). It is upon this third
element, materiality, that Barker’s claim fails.

   [7] The standard for materiality set out in Bagley is worth
repeating: Evidence is material if “there is a reasonable proba-
bility that, had the evidence been disclosed to the defense, the
result of the proceeding would have been different.” Bagley,
473 U.S. at 682. “A ‘reasonable probability’ is a probability
sufficient to undermine confidence in the outcome.” Id. In
analyzing the materiality factor, we heed the Supreme Court’s
instruction that the defendant need not show that he would
more likely than not have been acquitted had the evidence
been disclosed. Kyles, 514 U.S. at 434-35. Rather, the touch-
stone of the inquiry is whether Barker received a fair trial that
resulted in a verdict “worthy of confidence.” Id. at 434. We
examine the withheld evidence individually and cumulatively.
See id. at 436-37 & n.10.

  A.    MATERIALITY OF THE UNDISCLOSED CONVICTIONS

   [8] Barker argues that Abundiz’s four convictions were
material because they would have so undermined the credibil-
ity of a key prosecution witness that the jury could not have
  6
   With respect to the undisclosed convictions, the Washington Supreme
Court was concerned that there would be no constitutional violation if
Barker, who apparently had access to the same criminal history databases
as the prosecution, could have obtained the information through reason-
able diligence. The court also noted that it was not clear that a more thor-
ough search of the databases would have revealed a complete report of
Abundiz’s criminal history.
12610                  BARKER v. FLEMING
believed his story that Barker confessed. The convictions,
though, merely duplicate grounds for impeaching Abundiz
that were actually presented to the jury. See, e.g., United
States v. Croft, 124 F.3d 1109, 1124 (9th Cir. 1997) (withheld
psychiatric report that would have established witness’s mem-
ory loss was cumulative when defense had elicited fact of
memory loss on cross-examination); United States v.
Marashi, 913 F.2d 724, 733 (9th Cir. 1990) (withheld evi-
dence that would have contradicted trial testimony was cumu-
lative and not material because deposition contradicted trial
testimony in the same way).

   [9] The convictions surely would have highlighted
Abundiz’s dishonest nature, but we do not think that addi-
tional evidence of Abundiz’s penchant for lying would have
affected the jury when his proclivity for lying had already
been firmly established. The jury heard Abundiz admit that he
lied to the police about his identity by giving his brother’s and
cousin’s names instead of his own. He was caught in a lie on
the stand when he said he had used drugs for only a year and
a half but had to acknowledge a conviction for possession of
cocaine six years earlier. More important, the jury heard evi-
dence suggesting that Abundiz was lying about Barker’s con-
fession. When Abundiz first offered information about the
robbery, he had the details wrong: He called Barker “Parker”
and thought the name of the robbed store was “Pay ‘N Save,”
not “Payless.” The erroneous details permitted a strong infer-
ence that Abundiz may have fabricated the confession.
Finally, one of Abundiz’s jail-mates, who was not getting a
deal, testified that in early June, a few months after Barker
allegedly confessed, Abundiz said he knew nothing about the
robbery. The testimony suggests that Abundiz fabricated the
confessions sometime in June. All in all, Abundiz was por-
trayed as a serial liar whose story that Barker confessed was
highly doubtful.

  [10] The convictions might also have shown that Abundiz
was a career criminal desperate to escape from jail time. But
                           BARKER v. FLEMING                         12611
just as the jury knew that Abundiz was a liar, the jury also
knew that he had been in and out of jail several times. He
admitted to a juvenile conviction and the jury knew of the
three other crimes that were involved in his agreement with
the State. Specifically, the jury knew that Abundiz had been
charged with possession of narcotics and robbing a JC Penney
store, as well as that he was currently serving a 90-day sen-
tence.

   Only one conviction, the March 30, 1999, shoplifting con-
viction, is qualitatively different than the evidence introduced.
That conviction places Abundiz behind bars from March 29,
the date of the shoplifting incident, until April 9. Barker alleg-
edly confessed to Abundiz at a house behind a motel some-
time after Barker’s picture appeared on the news and before
Barker was arrested on April 10. According to Barker, the
jury was under the impression that the confession could have
occurred any time during the ten days that elapsed between
the robbery and Barker’s arrest. The withheld conviction,
Barker contends, whittles down the time span in which the
alleged confession could have taken place from ten days to
the thirty-two hours Barker and Abundiz were outside jail at
the same time.

   Where Barker misses the mark is that the conviction does
not whittle down the time period during which the confession
could have occurred from ten days to thirty-two hours.
Rather, the conviction reduces the possible time frame from
only about seventy-two hours to thirty-two hours. Abundiz
testified that Barker confessed after having seen his picture on
the news. The earliest date that Barker’s face could have
appeared on the news was April 7, the day Brown identified
him,7 meaning that the confession had to occur between April
   7
     The jurors were not informed of the exact date that Barker’s face was
shown on the news, but they were told of the date Brown identified
Barker. We surmise that the news probably did not identify Barker until
at least the next day, on April 8, when an arrest warrant was issued. In that
case, Abundiz’s March 30 conviction would only reduce the time during
which Barker could have confessed from about forty-eight hours to thirty-
two hours, an even smaller difference than the seventy-two hours we
assume based on the date of Brown’s identification.
12612                     BARKER v. FLEMING
7 and April 10. Thus, the jury was presented with a three-day
time frame, not a ten-day time frame. Seventy-two hours is
not a long time to begin with, and we doubt that jurors would
be significantly more skeptical of the confession had they
known that it had to occur during a thirty-two hour period.

   Here, the withheld evidence did not provide “the defense
with a new and different ground of impeachment.” Silva v.
Wood, No. 04-99000, 2005 WL 1732765, at *7 (9th Cir. July
26, 2005) (quoting Benn, 283 F.3d at 1056); see also Horton
v. Mayle, 408 F.3d 570, 580 (9th Cir. 2005) (although wit-
ness’s testimony was impeached by evidence of drug use,
lying to police, and assisting in the crime, withheld evidence
of promised immunity is a “wholly different kind of impeach-
ment evidence” and is material). The withheld convictions
were cumulative icing on an already crumbling cake.

  B.    MATERIALITY OF THE EVIDENCE RELATED                            TO
        ABUNDIZ’S RESIDENTIAL BURGLARY CHARGE

   [11] Barker makes two claims based on the evidence
related to Abundiz’s residential burglary charge.8 First, he
argues that the withheld evidence shows that Abundiz was
likely in his probable cause hearing at the time he claims to
have talked with Barker on June 14 around 10 a.m., a time
when one could infer that Barker confessed. The effort to
label this evidence as material fails because the facts do not
bear out Barker’s story line. Abundiz did not testify that
Barker confessed on June 14. Rather, he claimed only that
“Mr. Barker talked to [him] while in jail”9 (emphasis added)
  8
     To recap, the undisclosed evidence related to Abundiz’s residential
burglary charge is: 1) Documentation of Abundiz’s probable cause hearing
for a residential burglary; 2) A police report documenting a June 14, 1999,
meeting between a detective and Abundiz during which they discussed the
residential burglary charge; and 3) A June 16, 1999, order releasing
Abundiz and stating that the State decided not to charge him with residen-
tial burglary.
   9
     Abundiz did not testify about the June 14 meeting on direct examina-
tion.
                      BARKER v. FLEMING                  12613
on June 14. The alleged confession was on a different date.
Merely talking is vastly different from confessing. “A confes-
sion is like no other evidence. Indeed, the defendant’s own
confession is probably the most probative and damaging
evidence that can be admitted against him.” Arizona v.
Fulminante, 499 U.S. 279, 296 (1991) (internal quotation
marks and citation omitted). Thus, had the June 14 meeting
involved a purported confession, then evidence undermining
the likelihood that such a confession occurred would surely
hold more sway than evidence of a mere conversation. Unfor-
tunately for Barker, the evidence does not support his claim
of a June 14 confession.

   To the extent the timing of the probable cause hearing
undermines the June 14 conversation, it is of minimal signifi-
cance because the defense established at trial that Barker
probably was in another courtroom at that time. Whether
Barker was in one courtroom and Abundiz in another (accord-
ing to the withheld evidence), or whether Barker was in one
courtroom and Abundiz in a holding cell (according to the tes-
timony), the implication is the same. In either scenario, the
two men probably were in different places when Abundiz
claims they spoke.

   Barker’s second argument is that the withheld evidence
would have shown that the State agreed to drop a residential
burglary charge against Abundiz in exchange for favorable
testimony. From a series of events that occurred in June 1999,
Barker tries to craft a theory of collusion that the State
induced Abundiz to fabricate his testimony. Like the June 14
confession theory, this claim too rests on conjecture.

   According to Barker, the undisclosed evidence would tell
the following tale: On June 14, 1999, the same day Abundiz
claims he and Barker talked in the holding cell, Abundiz met
with the same detective who identified Barker based on
Brown’s description, Detective Salinas, to talk about the resi-
dential burglary. Detective Salinas’s report on the meeting
12614                  BARKER v. FLEMING
does not indicate that they discussed Abundiz’s burglary of a
JC Penney, which Salinas had written up only four days ear-
lier. Also absent is any notation that Abundiz had information
about the “clown robbery.” Barker is skeptical that Abundiz,
a drug addict facing a $20,000 bail, would have passed up an
opportunity to use his supposed knowledge about the Payless
robbery as a bargaining chip. Barker surmises that “[a] rea-
sonable juror would search for some other explanation for
why either Abundiz did not disclose the confession (i.e. it
never happened) or why Detective Salinas did not write it
down (i.e. it might not sound as credible coming from some-
body in Salinas’ position, being already involved and going
to testify in the following days in the first Barker trial).” The
suppression of the evidence prevented the defense from tell-
ing this tale because, without the evidence, Barker’s attorney
was not aware that Abundiz had met with Detective Salinas
the day Barker and Abundiz allegedly talked, or that the State
dropped the residential burglary charge against him.

   The flaw in Barker’s theory is that it is mere speculation.
Cf. Downs v. Hoyt, 232 F.3d 1031, 1037 (9th Cir. 2000)
(holding that undisclosed evidence of several leads in the
sheriff’s files was not material because defendant’s theory
that they might have helped his case was speculative and he
did not show how the evidence might have altered the out-
come). He has not pointed to any evidence that the State
induced Abundiz to conjure up confessions or that Detective
Salinas’s June 14, 1999, meeting with Abundiz involved the
Payless robbery. The most Barker can offer is a theory woven
largely of threads he has created himself to link pieces of evi-
dence. That is not enough: “The mere possibility that an item
of undisclosed information might have helped the defense, or
might have affected the outcome of the trial, does not estab-
lish ‘materiality’ in the constitutional sense.” Croft, 124 F.3d
at 1124 (quoting United States v. Agurs, 427 U.S. 97, 109-10
(1976)).

  Even if the prosecution did hide one of the benefits it gave
Abundiz, a deal involving the residential burglary charge
                      BARKER v. FLEMING                  12615
would have very nearly replicated evidence already admitted
that showed Abundiz received significant benefits for his tes-
timony. See United States v. Vgeri, 51 F.3d 876, 880 (9th Cir.
1995) (evidence of witness’s prior cooperation with law
enforcement was not material when the jury heard extensive
testimony about her cooperation with the Drug Enforcement
Agency). The jury knew that one burglary charge was being
dismissed, another reduced, and a sentence commuted.
Adding the dismissal of one additional charge to that list of
already substantial benefits would not add to the impeachment
value of the evidence. More importantly, the presence of such
a deal is pure speculation and surely not material.

  C.   MATERIALITY OF THE CUMULATIVE IMPACT            OF THE
       WITHHELD EVIDENCE

   [12] Thus far we have examined the force and nature of the
withheld evidence item by item, but our materiality analysis
is not complete until we consider the cumulative effect of the
suppressed evidence. Kyles, 514 U.S. at 436-37 & n.10
(courts must first evaluate the tendency and force of each item
of suppressed evidence and then evaluate its cumulative effect
at the end of the discussion). Gauging the collective impact of
the withheld evidence requires us to step back and consider
the strength of the prosecution’s case, paying close attention
to how critical Abundiz’s testimony was. See Banks v. Dretke,
540 U.S. 668, 700-01 (2004) (evidence impeaching witness
who was “the centerpiece” of a case that lacked physical evi-
dence was material); Strickler, 527 U.S. at 292-93 (evidence
impeaching important witness not material when the record
provided strong support for the conviction apart from the wit-
ness’s testimony); Horton, 408 F.3d at 578-79 (withheld evi-
dence was material when it impeached a witness who was
“central to the prosecution’s case”).

   [13] The heart of the prosecution’s case was Brown’s iden-
tification of Barker. Without physical or forensic evidence,
her testimony provided the only direct evidence that Barker
12616                 BARKER v. FLEMING
was the robber. Brown was approximately four feet away
from the robber for a couple of minutes during the robbery
and, during that time, she got a good look at his profile.
Brown was practiced at carefully looking at a person’s fea-
tures because of facial drawing classes she took and she made
a conscious effort to memorize her assailant’s profile. She
was extremely confident in her identification of Barker from
the photo montage. Her testimony and identification at trial
were categorical that Barker was the robber. Right away, she
said the picture “just kind of took my breath away because I
was like, that’s him . . . .”

   [14] We acknowledge that Brown’s identification was not
airtight. Her view was obstructed by the robber’s makeup and,
at times, by his handkerchief. Her description also became
more precise after she talked with co-workers who knew and
already distrusted Barker. Although she did not see any of his
tattoos, Brown stated that his hands were covered with mark-
ings and makeup. Nonetheless, the question we decide is not
whether we believe Brown, but whether we remain confident
in the verdict despite the potential damage the withheld evi-
dence would have wrought. In considering this question, we
appreciate the central importance of the identification by a
witness at the scene. “[D]espite its inherent unreliability,
much eyewitness identification evidence has a powerful
impact on juries,” Watkins v. Sowders, 449 U.S. 341, 352
(1981) (Brennan, J., dissenting), and the jury likely would
have convicted when presented with a confident eyewitness
like Brown whose trial testimony was clear and unwavering.
Significantly, Abundiz was not such a critical part of the case,
nor would the withheld evidence have so discredited him, that
our confidence is shaken.

   [15] A useful measurement of the importance of Abundiz
and the materiality of the withheld impeachment evidence is
the lack of emphasis the prosecutor placed on his testimony.
See Kyles, 514 U.S. at 444 (“The likely damage is best under-
stood by taking the word of the prosecutor. . . .” ); Horton,
                       BARKER v. FLEMING                    12617
408 F.3d at 580 (noting that the prosecutor’s emphasis on the
importance of the witness’s testimony highlights how impor-
tant the witness was to the case). The prosecutor spent most
of his closing argument reviewing Brown’s identification and
shoring up her testimony. The identification was the essential
platform of the State’s case. The prosecutor discussed
Abundiz’s testimony as corroborating evidence, but he
devoted only a small portion of his argument to Abundiz.
Unlike many cases in which withheld evidence is material
because it would have impeached a key witness, Abundiz was
not the glue holding together the prosecution’s case nor would
heaped-on impeachment evidence have altered his already
shattered credibility. Consequently, the cumulative impeach-
ment evidence is unlikely to have been the difference between
conviction and acquittal. See, e.g., Benn, 283 F.3d at 1046,
1054 (evidence was material when witness who would have
been impeached was “critical” to the prosecution); Carriger
v. Stewart, 132 F.3d 463, 466, 480-81 (9th Cir. 1997) (en
banc) (impeaching evidence was material when the physical
evidence was weak and the prosecution relied principally
upon the witness who would have been impeached).

   Barker makes much of the fact that the first jury that heard
his case without Abundiz’s testimony was hung but, when
Abundiz’s testimony was added, the jury returned a guilty
verdict. It oversimplifies the two trials to conclude that
Abundiz’s testimony was necessarily the difference between
a hung jury and a conviction. The fact that his testimony was
a key piece of different evidence is surely significant; it is not,
however, the defining factor standing alone. Instead, it must
be acknowledged that different juries may view the same facts
and testimony differently. In fact, the scope and nature of the
testimony was different at the two trials, although identifica-
tion by Brown remained firm. When he represented himself
at the first trial, Barker was relentless in his cross-examination
of Brown. Her testimony under fire from Barker covers forty-
seven pages. He hammered at issues relating to the tattoos,
makeup on the neck, markings on the hands, and ability to
12618                 BARKER v. FLEMING
observe the robber. At the second trial, Brown’s cross-
examination was a mere thirteen pages and Barker’s lawyer
told the judge, “We can see that the witness’s testimony has
changed from the first trial. I’m sure the holes will be plugged
up that way . . . .” We simply cannot conclude that Abundiz’s
testimony was necessarily the pivotal difference between the
two trials.

   The real question with respect to Abundiz is whether he
was telling the truth. Even absent the withheld evidence,
Abundiz was thoroughly impeached and showcased as a self-
serving jailhouse snitch. The alleged “confession” was wholly
suspect in light of the evidence. The withheld evidence simply
made it more so. But even without the undisclosed evidence,
the defense severely discredited Abundiz by highlighting his
deal with the State, his history of lying, his drug addiction,
and the errors in his initial statement. The difference between
the story of Abundiz that the jury knew and that which would
have been presented with the withheld evidence is not signifi-
cant. Contra Benn, 283 F.3d at 1057 (evidence was material
when the jury never heard that a key witness lied about any-
thing but suppressed evidence would have shown willingness
to lie about his testimony); Carriger, 132 F.3d at 480-81 (evi-
dence was material when prosecution portrayed star witness
as nonviolent and truthful but withheld evidence would have
shown that he was a sociopath, serial liar, and career felon).

   In sum, looking at the withheld evidence in a cumulative
sense, as well as than piece-by-piece, we are confident that
the withheld evidence would not have changed the jury’s cal-
culus of Abundiz as a witness. Given Brown’s powerful testi-
mony, we conclude that the withheld evidence was not
material.

  AFFIRMED.
