FOR PUBLICATION
 UNITED STATES COURT OF APPEALS
      FOR THE NINTH CIRCUIT

MICHAEL SLOVIK,                           No. 06-55867
             Petitioner-Appellant,           D.C. No.
                v.                      CV-05-00193-BEN/
JAMES A. YATES, Warden,                        NLS
            Respondent-Appellee.
                                            OPINION

       Appeal from the United States District Court
          for the Southern District of California
        Roger T. Benitez, District Judge, Presiding

                  Argued and Submitted
           April 9, 2008—Pasadena, California

                  Filed October 6, 2008

  Before: William C. Canby, Jr., Andrew J. Kleinfeld, and
               Jay S. Bybee, Circuit Judges.

                 Opinion by Judge Bybee




                          14145
14148                  SLOVIK v. YATES


                         COUNSEL

Kurt David Hermansen, Law Office of Kurt David Herman-
sen, San Diego, California, for the petitioner-appellant.

Garrett Beaumont, Deputy Attorney General of the State of
California, San Diego, California, for the respondent-appellee.


                         OPINION

BYBEE, Circuit Judge:

  California prisoner Michael D. Slovik petitions for a writ
of habeas corpus, contending that his confrontation rights
under the Sixth and Fourteenth Amendments to the United
States Constitution were violated when a California trial court
prevented him from asking questions on cross-examination
                           SLOVIK v. YATES                        14149
that would establish that one of the prosecution’s key wit-
nesses had likely lied under oath. The district court denied the
petition. For the reasons explained below, we agree that
Slovik was denied his confrontation rights and that the right
was clearly established; accordingly, we reverse.

               I.   FACTS AND PROCEEDINGS

   This case arises out of a billiard ball fight—not a billiard
hall fight, although it certainly was that as well—but a fight
involving billiard balls. On the evening of November 20,
1998, Slovik was drinking at a bar named Gusser’s Carousel.
It is clear that a bar fight occurred that night, and that Slovik
was one of the main belligerents in that fight. After that, the
details get kind of hazy. The various witnesses and
participants—as the State points out, indisputably not picked
from a Sunday school choir—offered conflicting testimony.1

   The prosecution relied largely on the eyewitness testimony
of the bartender, Katherine Buckley-Stoffel, and bar patrons
Mark Featherstone, Marilyn Woods, and Zachary Johnson.
The defense relied on the eyewitness testimony of bar patron
Bridgett Lewis. The trial error that is the subject of this appeal
occurred during Featherstone’s testimony. We are going to
relate the story as each of the witnesses recounted it.

   Buckley-Stoffel testified that at approximately 1:00 a.m.
she stopped serving Slovik alcohol because he was intoxi-
cated and antagonistic. In response, Slovik threw a tip at
Buckley-Stoffel, yelled obscenities, and threatened to kill her
as he was escorted outside. After Slovik was removed from
the bar, Buckley-Stoffel attempted to shut and lock the door,
but Slovik grabbed it, pushed her back inside, and then
  1
   Our recitation of the facts is drawn from the findings of fact in the
opinion of the California Court of Appeal, whose findings are presumed
correct unless rebutted by clear and convincing evidence. 28 U.S.C.
§ 2254(e)(1). Neither Slovik nor the State has challenged these findings.
14150                       SLOVIK v. YATES
shoved her and punched her in the shoulder. She testified that
Slovik grabbed pool balls2 and threw one toward Lewis and
one toward her, which came within six inches of her head and
broke the Plexiglas wall covering behind her. Buckley-Stoffel
saw Slovik on the floor with Featherstone standing over him
and then saw Slovik chasing Featherstone.

   Featherstone testified that Buckley-Stoffel took Slovik’s
drink after Slovik did backflips through the bar. According to
Featherstone, when Buckley-Stoffel asked Slovik to leave,
Slovik yelled, cursed and shoved her. Buckley-Stoffel
screamed for Featherstone to call 911. Featherstone further
testified that as he attempted to shut the door, Slovik grabbed
it and reentered the bar, shoving both Featherstone and
Buckley-Stoffel against the wall. Slovik chased Lewis, and
then slipped on pool sticks he had knocked down earlier. Fea-
therstone denied touching Slovik, but claimed that Slovik
chased him around the pool table, and threw two pool balls at
his face. When Featherstone ducked, the balls hit the wall,
and Slovik then threw a third ball.

   The incident that is the basis for Slovik’s habeas petition
occurred during Featherstone’s cross-examination. Feather-
stone was asked whether he was currently on probation. He
answered “no.” Slovik’s counsel apparently had a form estab-
lishing that Featherstone had been placed on five-years’ pro-
   2
     At oral argument, counsel for both sides indicated that cue balls were
thrown. We are fairly confident that not everyone was throwing cue balls,
although the record doesn’t reveal whether one side was stripes and the
other solids. Given that there seems to have been only one pool table at
the bar, there would only have been a single cue ball. Therefore, if Slovik
threw multiple balls they must have been pool balls and not cue balls. In
addition to the difference in color (the cue ball is, of course, white), on
coin-operated tables the owners use slightly larger and heavier cue balls,
or occasionally magnetic cue balls in order to ensure that the cue ball is
returned to the game after a scratch. See EWA MATAYA LAURANCE &
THOMAS C. SHAW, THE COMPLETE IDIOT’S GUIDE TO POOL & BILLIARDS 90
(1998).
                       SLOVIK v. YATES                   14151
bation for driving under the influence of alcohol, and he
wished to impeach Featherstone with this evidence. After an
unreported side-bar discussion, the trial court apparently sus-
tained a prosecution objection under California Evidence
Code § 352 to any further questioning of Featherstone about
his probationary status, ruling the inquiry would be too time
consuming. Although, due to the unrecorded side-bar, the
written record is ambiguous as to what exactly Slovik’s coun-
sel was attempting to introduce, at oral argument the State
conceded that Slovik’s counsel was not permitted to show
Featherstone the document and ask him an “isn’t it true that”
question.

   Woods testified that Johnson jumped on Slovik and they
began scuffling. Woods also testified that after Johnson and
Slovik scuffled, others unsuccessfully tried to remove Slovik
from the bar. Featherstone called 911 and Johnson ran out the
back door. Woods confirmed that Slovik shoved Buckley-
Stoffel and hit Buckley-Stoffel’s arm. She testified that while
Featherstone was on the other side of the pool table egging
him on, Slovik grabbed two pool balls and threw one of them.

   Johnson testified that he went to assist in the effort to
remove Slovik from the bar. According to Johnson, Slovik
swung at Buckley-Stoffel and missed, and when Johnson
stepped in the way, Slovik swung at him instead, and they
began fighting. Johnson hit Slovik twice in the back of the
head and they fell.

  The defense relied principally on the testimony of Lewis,
another customer at the bar that night. According to Lewis,
Slovik was intoxicated and belligerent and refused to leave
until Buckley-Stoffel accompanied him to the door. When
Lewis heard a disturbance, she went outside and witnessed
Johnson holding Slovik in a chokehold against a car, as John-
son’s sister screamed to “let him go!” Lewis testified that
Slovik followed Johnson back into the bar, and when Lewis
and Buckley-Stoffel attempted to shut the door, Slovik pushed
14152                        SLOVIK v. YATES
Buckley-Stoffel aside and entered the bar. Lewis then kicked
Slovik; he threatened her, and she ran outside. Lewis wit-
nessed Featherstone pushing Slovik, and then kicking and
pushing him back down when he tried to get up. Lewis testi-
fied that after Slovik got up he angrily threw pool balls in an
erratic fashion “not to pinpoint anybody out. He was just
throwing them to throw them.” On cross-examination Lewis
testified that she was unsure what he was trying to hit: “I
guess people. I don’t know how.” She further testified that as
Slovik moved toward the door, Featherstone threw a ball in
that direction.3

   As a result of the bar fight, Slovik was charged with assault
with a deadly weapon (the pool balls) and by means of force
likely to produce great bodily injury upon Buckley-Stoffel
(count one), and upon Featherstone (count two) in violation
of California Penal Code § 245(a)(1); and battery upon Fea-
therstone (count three) and Buckley-Stoffel (count four) in
violation of California Penal Code § 242. A jury found Slovik
guilty of counts two and four as charged, guilty of the lesser
included offense of simple assault for count one, and not
guilty of count three. On June 28, 1999, the trial court sen-
tenced Slovik to 40 years to life as a result of the California
three-strikes law and other sentencing enhancements.
   3
     Lewis testified that when the police asked them to write statements,
they discussed the events among themselves, and Featherstone indicated
that they should not mention that he had pushed or kicked Slovik.
Although she wrote that Slovik hit Buckley-Stoffel, she testified that she
meant that he pushed Buckley-Stoffel when being escorted out of the bar.
She explained that she did not mention the parking lot fight in her state-
ment because the police told them to write about the incident in the bar.
Lewis also failed to note in her written statement that Featherstone had
thrown a pool ball, but she testified that she decided to tell the truth when
she learned that Slovik would receive a long sentence.
   A defense investigator testified that when he interviewed Lewis she
never mentioned anyone besides Slovik throwing pool balls, but she did
state that Featherstone pushed Slovik to the ground and then kicked him,
and that Buckley-Stoffel and Featherstone did not plan to inform the
police about either that or the parking lot fight.
                           SLOVIK v. YATES                14153
   Slovik appealed his conviction on numerous grounds. The
California Court of Appeal affirmed Slovik’s conviction on
the merits, but struck some of the sentencing enhancements in
an unpublished decision. The California Supreme Court
denied Slovik’s petition for review. In September 2001,
Slovik was resentenced to 35 years to life, which the Califor-
nia Court of Appeal affirmed in another unpublished decision.
Slovik then filed a state habeas corpus petition, which was
denied by the Superior Court, the state appellate court, and the
California Supreme Court.

   In February 2005, Slovik filed a 28 U.S.C. § 2254 petition
for writ of habeas corpus in federal district court. Magistrate
Judge Stiven recommended that the habeas petition be denied,
and Judge Benitez adopted that recommendation and denied
the petition on May 1, 2006. Slovik timely appealed.

                     II.      DISCUSSION

   This case is governed by the Antiterrorism and Effective
Death Penalty Act (“AEDPA”), 28 U.S.C. § 2254(d). See
Lindh v. Murphy, 

, 327 (1997). Under AEDPA,
we may not grant Slovik habeas relief unless the last reasoned
state court adjudication, here the California Court of Appeal’s
first unpublished decision addressing the merits of his case,
“(1) 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; or
(2) resulted in a decision that was based on an unreasonable
determination of the facts in light of the evidence presented
in the State court proceeding.” 28 U.S.C. § 2254(d). We
review de novo a district court’s decision to deny a habeas
petition. Campbell v. Rice, 

, 1169 (9th Cir.
2005) (en banc).

   We granted a certificate of appealability on two questions:
(1) whether Slovik’s constitutional rights were violated by the
trial court’s exclusion of evidence that would have impeached
14154                   SLOVIK v. YATES
Featherstone; and (2) whether Slovik’s right to present a
defense was violated by the assault instruction given to the
jury. Because we find the limitation on use of impeachment
evidence for cross-examination adequate to grant the petition,
we do not reach the jury instruction issue.

A.   Confrontation Clause Violation

   [1] The Confrontation Clause of the Sixth Amendment
guarantees a criminal defendant the right “to be confronted
with the witnesses against him.” U.S. CONST. amend. VI. The
Supreme Court has explained that the right of confrontation
“means more than being allowed to confront the witness
physically,” but rather “[t]he main and essential purpose of
confrontation is to secure for the opponent the opportunity of
cross-examination.” Davis v. Alaska, 

, 315-16
(1974) (internal quotation marks and citation omitted). The
Confrontation Clause does not prevent a trial judge from
imposing “reasonable limits on such cross-examination based
on concerns about, among other things, harassment, prejudice,
confusion of the issues, the witness’ safety, or interrogation
that is repetitive or only marginally relevant.” Delaware v.
Van Arsdall, 

, 679 (1986). Nevertheless, the
Court has held that a defendant’s Confrontation Clause rights
have been violated when he is “prohibited from engaging in
otherwise appropriate cross-examination . . . and thereby ‘to
expose to the jury the facts from which jurors . . . could
appropriately draw inferences relating to the reliability of the
witness.’ ” 

(quoting 

). “[A]
criminal defendant states a violation of the Confrontation
Clause by showing that he was prohibited from engaging in
otherwise appropriate cross-examination designed to show a
prototypical form of bias on the part of the witness.” 

defendant has met his burden when he has
shown that “[a] reasonable jury might have received a signifi-
cantly different impression of [a witness’] credibility had . . .
counsel been permitted to pursue his proposed line of cross-
examination.” 

YATES                         14155
   [2] Slovik’s Sixth Amendment right to be confronted with
the witnesses against him was violated because a reasonable
jury might have received a “significantly different impres-
sion” of Featherstone’s credibility had Slovik been permitted
to confront Featherstone with the record of probation and
cross-examine him concerning his apparent lie under oath.
See 

cross-examination of Featherstone,
Slovik’s counsel asked “You’re currently on probation right
now?” to which Featherstone responded “No.” When, during
cross-examination, Slovik’s counsel attempted to approach
Featherstone with evidence that Featherstone was in fact on
probation, the trial court denied permission to approach the
witness with that evidence. Had Slovik’s counsel been permit-
ted to ask Featherstone something along the lines of “isn’t it
true that you are currently on probation for driving under the
influence of alcohol?” Slovik might have shown that Feather-
stone’s prior statement, made under oath, that he was not on
probation was a lie.4

   [3] The evidence that Featherstone was placed on five-
years’ probation for driving under the influence was not being
proffered to establish that Featherstone was unreliable
because he was on probation, but rather to establish that Fea-
therstone was unreliable because he had lied about being on
probation. It is clear to us that the jurors might have formed
a significantly different impression of Featherstone’s credibil-
ity if they had heard cross-examination showing that Feather-
stone was willing to lie under oath.5 Therefore, the trial
  4
     At oral argument the State suggested that Featherstone was not neces-
sarily lying because he may not have known that he was on probation.
Whether Featherstone might have been innocently mistaken in telling
what he thought to be the truth when he spoke falsely was a question to
be argued by counsel and resolved by the jury.
   5
     Slovik also argues that if Featherstone was on probation, he would
have had an added motive for lying about whether he attacked Slovik first,
because an assault or battery charge would have violated the terms of his
probation. The State argues in response that Slovik never advised the trial
14156                       SLOVIK v. YATES
court’s refusal to allow Slovik to present such evidence vio-
lated Slovik’s constitutional rights under the Sixth Amend-
ment, so clearly set forth in Van Arsdall and Davis.

   The State concedes that the exclusion of the proffered
impeachment cross-examination would violate Slovik’s Sixth
Amendment confrontation rights if the excluded testimony
would have produced a significantly different impression of
the witness’ credibility, but it contends that exclusion of
cross-examination with the record of Featherstone’s probation
did not significantly alter the jurors’ impression of Feather-
stone’s credibility. Inexplicably, the State argues that “[j]urors
could reasonably infer from defense counsel’s cross-
examination question and Featherstone’s answer that Feather-
stone committed an offense resulting in a prior placement on
probation.” The entire exchange proceeded as follows:
Slovik’s counsel asked Featherstone, “You’re currently on
probation right now?” to which Featherstone responded “No.”
It is baffling how jurors could reasonably infer from this
exchange that Featherstone committed an offense resulting in
a prior placement on probation. The only conclusion that a
juror could reasonably draw is that Slovik’s counsel was
attempting to impeach Featherstone’s credibility, but failed.
Indeed, because use of the evidence was prohibited, it would
have been improper for the jurors to read anything else into

court, pursuant to California Evidence Code § 354(a), that he intended to
pursue evidence of Featherstone’s current probation status to show Fea-
therstone had a motive for testifying falsely. Although California evidenti-
ary law is irrelevant to the determination of whether Slovik’s
constitutional rights were violated, the State’s position may be construed
as an argument that Slovik forfeited the motive argument by failing to
exhaust it before the California Court of Appeal. See Picard v. Connor,

, 276 (1971) (explaining that a state prisoner seeking habeas
review is required “to present the state courts with the same claim he urges
upon the federal courts.”) We need not decide whether Slovik’s motive
argument is exhausted because the excluded cross-examination is crucial
to establish that Featherstone had lied under oath regardless of whether it
also establishes a motive for Featherstone to lie.
                        SLOVIK v. YATES                   14157
the exchange. The State has not offered any reason why the
jury would suspect that Featherstone was lying when he
answered “No.” The jurors were left to assume that Slovik’s
counsel was fishing and that Featherstone testified honestly.

   The State also contends that the trial court’s ruling did not
significantly alter the jury’s impression of Featherstone’s
credibility because Slovik’s trial counsel had already estab-
lished that some of the prosecution’s witnesses were regular
bar patrons, and some were on probation, and that this “suf-
ficed to dispel any lingering illusions that the prosecutor
picked his witnesses from a Sunday school choir.” This argu-
ment fails to recognize the effect that cross-examination
might have had on the jurors’ perception of the individual wit-
ness. Although we will consider this argument again in our
harmless error analysis, the fact that defense counsel
impeached other witnesses bears no relevance in the confron-
tation right analysis, which asks whether impeaching Feather-
stone would have produced a significantly different
impression of Featherstone’s credibility. Featherstone was an
important witness. He was in the middle of the dust-up and,
if his testimony was believed, was a victim of Slovik’s
billiard-ball assault. The Supreme Court has emphasized that
“the focus of the Confrontation Clause is on individual wit-
nesses” and thus “the focus of the prejudice inquiry in deter-
mining whether the confrontation right has been violated must
be on the particular witness, not on the outcome of the entire
trial.” Van 

. That defense counsel was
able to impeach other witnesses is irrelevant to whether the
trial court’s limit on Slovik’s ability to cross-examine Fea-
therstone violated the Confrontation Clause.

  [4] The California Court of Appeal analyzed Slovik’s claim
as an evidentiary issue governed by state law, rather than a
confrontation question governed by the Sixth Amendment.
The California Court of Appeal approved the trial court’s rul-
ing under California Evidence Code § 352, which states:
14158                   SLOVIK v. YATES
     The court in its discretion may exclude evidence if
     its probative value is substantially outweighed by the
     probability that its admission will (a) necessitate
     undue consumption of time or (b) create substantial
     danger of undue prejudice, of confusing the issues,
     or of misleading the jury.

Applying a California evidentiary standard of review, the
Court of Appeal concluded that “[a]bsent a clear showing of
abuse, the trial court’s exercise of discretion under this section
will not be reversed.” See People v. Avila, 

,
1137 (Cal. 2006) (“We review for abuse of discretion a trial
court’s rulings on relevance and the exclusion of evidence
under Evidence Code section 352.”). AEDPA gives us no
basis here for questioning a California court’s decision apply-
ing its own evidentiary rules. By treating the issue exclusively
as an evidentiary question, rather than a constitutional ques-
tion, however, the Court of Appeal simply applied the wrong
standard; had the Court of Appeal applied Van Arsdall and
Davis, we believe it would have come to a different conclu-
sion. In this regard, the California Court of Appeal’s decision
was contrary to or involved an unreasonable application of
clearly established Supreme Court precedent regarding the
Confrontation Clause.

B.   Harmless Error Analysis

   [5] Confrontation Clause errors are subject to harmless-
error analysis. “The correct inquiry is whether, assuming that
the damaging potential of the cross-examination were fully
realized, a reviewing court might nonetheless say that the
error was harmless beyond a reasonable doubt.” Van 

. In any particular case the relevant factors
include “the importance of the witness’ testimony in the pros-
ecution’s case, whether the testimony was cumulative, the
presence or absence of evidence corroborating or contradict-
ing the testimony of the witness on material points, the extent
                        SLOVIK v. YATES                   14159
of cross-examination otherwise permitted, and, of course, the
overall strength of the prosecution’s case.” 

factors, we cannot say that the trial court’s
limit on Slovik’s ability to cross-examine Featherstone was
harmless beyond a reasonable doubt. Assuming, as we must,
that the damaging potential of Featherstone’s cross-
examination was fully realized, the jury could have concluded
that Featherstone was willing to lie under oath and could have
discounted his testimony.

   [6] The conviction at issue in Slovik’s habeas petition is
count two, assault with a deadly weapon, for throwing pool
balls at Featherstone. Featherstone’s testimony is critical to
that conviction because Featherstone testified plainly that
Slovik threw one or more pool balls at him. The only other
witness who testified that Slovik may have thrown a pool ball
at Featherstone is Woods. According to the California Court
of Appeal, Woods testified that “while Featherstone was on
the other side of the pool table egging him on, [Slovik] threw
one of the balls.” Given that Slovik’s defense was based on
self defense, and he argued that Featherstone was the aggres-
sor, it is far from clear beyond a reasonable doubt that
Woods’ testimony—that Slovik “threw one of the balls” while
Featherstone was egging him on—would suffice for a jury to
convict Slovik of assault with a deadly weapon. Woods’ testi-
mony did not even indicate that Slovik was aiming at Feather-
stone, as opposed to just throwing a ball aimlessly. Moreover,
Woods only testified that Slovik threw one ball and does not
indicate the target of that ball, whereas Featherstone con-
tended that Slovik threw three balls at him. Other witnesses
testified either that Slovik threw pool balls haphazardly, or
that he threw them at others. Lewis, for example, testified that
Slovik “was just throwing [pool balls] to throw them” and
was not trying “to pinpoint anybody.” Featherstone’s testi-
mony thus appears crucial to the prosecution’s case and is not
cumulative. We cannot conclude that the prosecution’s case
was so strong that the trial court’s decision to exclude cross-
14160                   SLOVIK v. YATES
examination on evidence discrediting Featherstone was harm-
less error beyond a reasonable doubt.

   The State does not attempt to argue that its case was partic-
ularly strong, or that Featherstone was inconsequential to its
conviction. Rather, the State alleges that even if the state court
committed constitutional error, “the state court trial jurors
knew that none of the trial witnesses led a purely law-abiding
life.” We are not sure what we should take from this admis-
sion. This argument is presumably an attempt to show that the
testimony was cumulative, but it merely serves to emphasize
that the State’s case rested on the testimony of shaky wit-
nesses and reminds us that if these witnesses were further
contradicted, the jury might not have returned a conviction.

   [7] The California Court of Appeal found “harmless error
in the court’s excluding evidence a witness was on probation
when the witness testified to the contrary.” People v. Slovik,
No. SCE193584, at 2 (Cal. Ct. App. filed Mar. 2, 2001). The
court provided no reasoning to support that statement. The
court’s analysis is limited to another conclusory statement that
“there is no reasonable probability of a different result had the
court allowed questioning of Featherstone’s probationary sta-
tus.” 

The court fails to explain why there is no rea-
sonable probability of a different result, in light of any of the
factors provided by the Supreme Court to guide the harmless
error inquiry. Instead, the court just concludes for a third time
that “[t]he fact [that] the defense was not allowed to question
Featherstone further about whether he was on probation did
not result in a miscarriage of justice.” 

is
unclear whether the California Court of Appeal simply failed
to conduct a harmless error analysis, or whether it misapplied
that analysis, its conclusion that the trial court’s exclusion of
the evidence of Featherstone’s probation was harmless error
either contradicted or unreasonably applied established fed-
eral law as determined by Supreme Court precedent. See Van

.
                            SLOVIK v. YATES                14161
                     III.     CONCLUSION

   [8] We reverse the denial of the petition, and direct the dis-
trict court to issue an order stating that a writ of habeas corpus
will be issued with regard to Slovik’s assault conviction
unless he is retried or resentenced within a reasonable period
of time to be determined by the district court.

  REVERSED AND REMANDED.