                    FOR PUBLICATION
  UNITED STATES COURT OF APPEALS
       FOR THE NINTH CIRCUIT

THOMAS LESTER STARK,                          No. 03-17241
            Petitioner-Appellant,
              v.                                D.C. No.
                                             CV-02-00290-MMC
ROD HICKMAN, WARDEN,
                                                 OPINION
            Respondent-Appellee.
                                         
        Appeal from the United States District Court
           for the Northern District of California
        Maxine M. Chesney, District Judge, Presiding

                  Argued and Submitted
        October 21, 2005—San Francisco, California

                      Filed August 1, 2006

    Before: Sidney R. Thomas and William A. Fletcher,
    Circuit Judges, and James C. Mahan,* District Judge.

                    Opinion by Judge Mahan




  *The Honorable James C. Mahan, United States District Judge for the
District of Nevada, sitting by designation.

                               8567
8570                   STARK v. HICKMAN


                          COUNSEL

John J. Jordan, San Francisco, California, for the petitioner-
appellant.

John Deist, Office of the California Attorney General, San
Francisco, California, for the respondent-appellee.


                          OPINION

MAHAN, District Judge:

   Thomas Stark, a California state prisoner, appeals the dis-
trict court’s dismissal of his pro se 28 U.S.C. § 2254 habeas
corpus petition. Stark contends that his federal right to due
process was violated at his California state trial for murder
when the trial court charged the jury during the guilt phase
that he was to be presumed “conclusively sane” by the jury.

               I.   STANDARD OF REVIEW

   The district court’s decision to dismiss a petition for a writ
of habeas corpus under 28 U.S.C. § 2254 is reviewed de novo.
Patterson v. Gomez, 223 F.3d 959, 962 (9th Cir. 2000). The
petition at issue here was filed after 1996; as such, it is gov-
erned by the Antiterrorism and Effective Death Penalty Act of
1996 (AEDPA). See 28 U.S.C. § 2254(d); Williams v. Taylor,
529 U.S. 362, 402 (2000) (O’Connor, J., concurring). Under
                          STARK v. HICKMAN                  8571
AEDPA, a federal court can reverse a state court decision
denying relief only if that decision was “contrary to, or
involved an unreasonable application of,” clearly established
Supreme Court precedent. 28 U.S.C. § 2254(d)(1).

   A state court’s decision is contrary to clearly established
Supreme Court precedent if the state court arrives at a conclu-
sion opposite to that reached by the Supreme Court on a ques-
tion of law, or reaches a different conclusion based on facts
materially indistinguishable from a Supreme Court case.
Penry v. Johnson, 532 U.S. 782, 792 (2001). A state court’s
decision constitutes an unreasonable application of Supreme
Court precedent if the state court identifies the correct govern-
ing legal principles, but the application of law to the facts is
objectively unreasonable. Id. An unreasonable application is
different from an incorrect or erroneous application of federal
law. Id. at 793. Accordingly, a federal habeas court may not
issue the writ simply because that court concludes in its inde-
pendent judgment that the relevant state-court decision
applied clearly established federal law erroneously or incor-
rectly. Rather, that application must also be unreasonable. Id.

   Furthermore, even if the state court’s ruling is clearly con-
trary to or an unreasonable application of Supreme Court pre-
cedent, such an error would justify relief only if the error had
a “substantial and injurious effect or influence in determining
the jury verdict.” Penry, 532 U.S. at 795 (quoting Brecht v.
Abrahamson, 507 U.S. 619, 637 (1993)); see also Shackleford
v. Hubbard, 234 F.3d 1072, 1079 (9th Cir. 2000).

                    II.    BACKGROUND

   Petitioner Thomas Stark and his wife Marilyn Stark were
married in 1972 and had two children. In 1995, Marilyn began
having an affair with Steven Johnson. She informed petitioner
of the affair during the summer of 1996 and shortly thereafter
moved into an apartment with Johnson.
8572                   STARK v. HICKMAN
   After he learned of the affair, petitioner’s behavior began
to change. He lost weight, could not sleep, became depressed,
wept frequently and often spoke of committing suicide. He
also threatened to kill Johnson and then himself if Marilyn did
not end the affair.

   About two weeks after Marilyn moved in with Johnson,
petitioner visited the apartment and confronted Johnson. Peti-
tioner punched Johnson in the chest and told him that if he
caught Johnson there again, he would kill him. Several weeks
later, petitioner returned to the apartment and again con-
fronted Johnson, threatening to kill him.

   On February 24, 1997, petitioner and Marilyn went out to
dinner to discuss their relationship and the possibility of a rec-
onciliation. However, at the restaurant, Marilyn informed
petitioner that she would not be moving back home. They left
the restaurant. On their way back to petitioner’s home, peti-
tioner noticed Johnson following them in his truck. When
petitioner and Marilyn arrived home, Johnson pulled up to the
house. He was driving fast and “burned rubber” before stop-
ping to park. Marilyn had told Johnson that she was going to
ask petitioner for a divorce and the two had agreed to meet
later that evening.

    When Johnson approached petitioner’s house, Marilyn
went outside and spoke with him in the front yard. Petitioner,
who had been in the kitchen, came out onto the porch with a
gun. He waived the gun in the air and told Johnson, “Leave,
little worm.” Johnson told petitioner to put down the gun and
fight like a man. Johnson then got into his truck and left. Peti-
tioner and Marilyn returned to the kitchen and petitioner
talked about committing suicide.

   About 45 minutes to an hour later, Johnson returned to peti-
tioner’s house. Marilyn went outside and told Johnson to
leave and that she would meet him after consoling petitioner.
Petitioner, who was at the kitchen window, told Johnson to
                      STARK v. HICKMAN                    8573
leave, and Johnson in turn yelled at petitioner to come out.
Eventually, Marilyn persuaded Johnson to leave. Marilyn left
the house sometime thereafter and drove to a bowling alley to
look for Johnson. She returned about 15 minutes later and
pulled into the driveway of a neighbor. Petitioner came out of
his house and told Marilyn to park the car and come into the
house. He informed Marilyn that he had spoken with Johnson,
that Johnson was coming over, and that he was going to “set-
tle this” matter and fix Johnson once and for all.

   Johnson arrived at petitioner’s house a short time later.
Petitioner went outside with a revolver and met Johnson on
the sidewalk, calling him a little worm. Johnson told peti-
tioner to put the gun down and fight like a man. Petitioner and
Johnson began pushing each other. During the scuffle, peti-
tioner stumbled and fired his gun into the ground. Petitioner
regained his balance and pushed Johnson against a wall
between the garage and house. He pointed the gun at John-
son’s torso area and made a mocking gunshot sound —
“boom, boom.” The two then resumed their pushing match
and the gun went off, shooting Johnson in the stomach. The
neighbor ran into petitioner’s house to call the police and saw
that Marilyn was already on the telephone with 911. The
neighbor went back outside and saw that petitioner was lean-
ing over Johnson. When he turned to go back to the house, he
heard at least two more gunshots.

  Marilyn was on the phone with the 911 dispatcher when
she heard the shots. Within a minute, she heard three more
shots. When she came out, Johnson was lying on the ground
on his side and petitioner was leaning over him. Petitioner
nudged or kicked Johnson’s head, saying that Johnson was
dead. Petitioner went back inside the house, unloaded the gun
and put it on the counter. He then swallowed a large quantity
of pills and walked out the back door.

  When police and firefighters arrived on the scene, they
found Marilyn cradling Johnson, who was lying on the walk-
8574                   STARK v. HICKMAN
way. Police officers did not find a knife or weapon in John-
son’s possession or near him on the ground. Johnson was then
taken by ambulance to the hospital, where a hospital orderly
found a knife in the sheets of the hospital gurney on which
Johnson had been placed.

   Officers eventually entered petitioner’s house and found
the gun, five expended shells, checks from petitioner to his
children, and letters from petitioner to his family and friends.
They later found petitioner unconscious in a pickup truck in
front of his parents’ house and arrested him.

   Johnson did not survive the shooting. A forensic patholo-
gist found that the cause of death was multiple gunshot
wounds. The pathologist opined that Johnson most likely suf-
fered a gunshot wound to his abdomen first, followed by a
shot in the neck and two shots in the back.

   Petitioner was charged with first degree murder and per-
sonal use of a firearm in California state court. He pled not
guilty and, alternatively, not guilty by reason of insanity. In
accordance with California’s standard practice, petitioner’s
state jury trial was bifurcated into a guilt phase and a sanity
phase. At the conclusion of the first phase of trial, the trial
court charged the jury that petitioner was to be presumed
“conclusively sane.” The jury found petitioner guilty of first
degree murder and found the firearm allegation to be true. At
the second phase of the trial, the jury found petitioner was
legally sane at the time of the offense charged. Petitioner
thereafter moved for a new trial or, alternatively, for modifi-
cation of the verdict. The trial court granted petitioner’s alter-
native motion to modify verdict, finding the evidence
insufficient to support the verdict of murder in the first
degree. Accordingly, the court reduced the verdict to second
degree murder.

   After unsuccessful direct appeals in state court, petitioner
filed a federal petition for a writ of habeas corpus pursuant to
                       STARK v. HICKMAN                      8575
28 U.S.C. § 2254, challenging California’s jury instruction on
the presumption of sanity and the trial court’s refusal to give
an instruction on antecedent threats. The district court denied
the petition and then issued a certificate of appealability only
as to the former issue. Because this court has not granted a
certificate of appealability as to the latter, it declines to
expand the scope of the appeal by considering any claim relat-
ing to antecedent threats. See 28 U.S.C. § 2253; Slack v.
McDaniel, 529 U.S. 473 (2000).

                     III.   DISCUSSION

  A.   Presumption of Sanity Instruction

   We first address whether the trial court’s instruction during
the guilt phase of the trial that the jury was to conclusively
presume petitioner was sane violated his right to due process.

   In California, there are two purposes for which a criminal
defendant may introduce evidence that he suffers from a men-
tal disease, defect or disorder. First, the defendant may plead
not guilty to the offense charged and second, not guilty by
reason of insanity. See Patterson v. Gomez, 223 F.3d 959, 965
(9th Cir. 2000). When such a plea is entered, the court con-
ducts a bifurcated trial. Id. at 964. In the first phase of trial,
the defendant’s guilt is determined without reference to his
plea of insanity. Id. If the defendant is found guilty, the trial
proceeds to a second phase in which his legal sanity is deter-
mined. Id.

   Petitioner in this case contended during the guilt phase that
he did not possess the mental state required for first degree
murder. In support of his contention, the defense called two
psychiatrists, who testified that petitioner suffered from a
“major depressive disorder and “an acute stress disorder”
prior to and at the time of the shooting. According to the
defense, such testimony established that, on the night in ques-
tion, petitioner did not form the requisite mens rea for murder.
8576                   STARK v. HICKMAN
   At the conclusion of the guilt phase of petitioner’s trial, the
trial court instructed the jury to conclusively presume peti-
tioner was sane:

    In the guilt phase of a criminal action the defendant
    is conclusively presumed to be sane; however, you
    have received evidence regarding a mental defect or
    mental disorder of the defendant at the time of the
    commission of the crime charged, namely, murder of
    the first degree, murder of the second degree, or the
    lesser crime thereto, namely, voluntary manslaugh-
    ter. You should consider this evidence solely for the
    purpose of determining whether the defendant actu-
    ally formed the required specific intent, premedi-
    tated, deliberated, or harbored malice aforethought
    which are an element of the crime charged, namely
    murder of the first degree, murder of the second
    degree, or the lesser crime of voluntary manslaugh-
    ter.

Petitioner argues that this instruction, given without a defini-
tion of insanity, led the jurors to believe they could not con-
sider whether petitioner’s alleged mental disability precluded
him from forming the requisite intent to commit murder. Peti-
tioner contends that as a result, the instruction had the effect
of lowering the state’s burden of proving the requisite intent,
thereby violating his right to due process.

  The California Court of Appeal rejected petitioner’s argu-
ment, holding there was no possibility that petitioner was
prejudiced by the trial court’s instruction. In so ruling, the
Court of Appeal relied on the California Supreme Court’s
decision in People v. Coddington, 23 Cal. 4th 529 (2000),
overruled on other grounds, Price v. Superior Court, 25 Cal.
4th 1046 (2001). In Coddington, the California Supreme
Court addressed a defendant’s claim that the presumption of
sanity instruction given during the guilt phase of his trial prej-
udicially undermined his defense of lack of premeditation
                       STARK v. HICKMAN                      8577
because the jury could have concluded that evidence of his
mental illness could not be considered. Id. at 584-85. The
court held that the instruction correctly stated the law and
noted that the defendant neither objected to the instruction nor
sought modification. Id. at 584 (“A defendant who believes
that an instruction requires clarification must request it.”). The
court nevertheless held that the defendant suffered no preju-
dice because: (1) the instruction expressly advised the jury
that evidence of a mental disease or defect could be consid-
ered in determining if the requisite mental states were present;
and (2) the prosecutor and defense counsel argued the pres-
ence or absence of mental disease during closing arguments,
with defense counsel reminding the jury that whether the
defendant was mentally ill was for the jury to determine. Id.
at 584-85. The Court of Appeal found Coddington dispositive
of the instant case, noting that as in Coddington, petitioner did
not object to or seek modification of the instruction below.
Furthermore, “the jury was instructed that it could consider
the evidence of [petitioner’s] mental defect or mental disorder
in determining whether he formed the requisite specific intent
and the issue of [petitioner’s] mental state was vigorously
debated during the closing arguments of both the prosecutor
and defense counsel.” Id.

   Petitioner contends that the Court of Appeal’s decision was
contrary to or involved an unreasonable application of clearly
established federal law, as determined by the Supreme Court.
Petitioner’s primary authority is this court’s decision in Pat-
terson v. Gomez, 223 F.3d 959 (9th Cir. 2000), which
declared a similar instruction on the presumption of sanity to
be unconstitutional.

   Before we proceed to a discussion of Patterson, we find
that contrary to the California Court of Appeal’s conclusion,
Coddington is not dispositive of the instant issue. While the
California Supreme Court stated in Coddington that the pre-
sumption of sanity instruction “correctly states the law,” id. at
584, it did not address the exact holding in Patterson, i.e.,
8578                      STARK v. HICKMAN
whether instructing the jury of this conclusive presumption
violates due process. Specifically, the issue presented in Cod-
dington was whether the presumption of sanity instruction
given Coddington during the guilt phase of the defendant’s
trial was error which prejudicially undermined his guilt phase
defense of lack of premeditation of the murders charged. Id.
Thus, the Coddington court neither addressed the constitution-
ality of the instruction itself nor rendered a decision with
regard to it. Rather, the court merely found, on the facts of
that case, that the defendant was not prejudiced by the chal-
lenged instruction. Therefore, Coddington is not on point
because the issue presented in this case was not actually
decided there. In any event, the Court of Appeal’s decision
does not readily explain how the facts of this case were mate-
rially distinguishable from those in Patterson.

   In Patterson, the defendant was charged with murdering his
daughter. Id. at 961. The killing occurred while the two were
sitting beside a California highway. Id. Patterson picked up
the girl and lunged in front of a large semi truck, killing her
and injuring himself. Id. Patterson had a history of depression
and had been hospitalized once after an attempted suicide. Id.
At the time of the killing, he was experiencing serious marital
and financial difficulties, had not slept for days, and had
stopped taking his prescribed psychotropic medications. Id.
Patterson was charged with first degree murder and pled not
guilty and not guilty by reason of insanity. Id. At the conclu-
sion of the guilt phase of trial, the jury was instructed to pre-
sume that Patterson was sane at the time of the charged offense,1
  1
    The following instruction was given during the guilt phase of Patter-
son’s trial:
    Evidence has been received regarding a mental disease or mental
    disorder of the defendant at the time of the crime in the informa-
    tion. You may consider such evidence solely for the purpose of
    determining whether or not the defendant actually formed the
    mental state which is an element of the crime charged in the
    information, and are [sic] found in the definitions of murder.
                          STARK v. HICKMAN                           8579
and he was convicted of first degree murder. Id. at 961-62.
The same jury then hung on the question of whether Patterson
was sane. Id. at 962. A second jury, empaneled to try only the
sanity question, found Patterson sane. Id.

   The Ninth Circuit subsequently set aside Patterson’s con-
viction, declaring that the California jury instruction on the
presumption of sanity violated due process. Id. at 966. In so
ruling, the court relied upon the federal law established by the
Supreme Court in Sandstrom v. Montana, 442 U.S. 510
(1979), and Francis v. Franklin, 471 U.S. 307 (1985). Both
of these cases involved jury instructions that were found
unconstitutional because they shifted the burden of proof to
the defendant.

   [1] In Sandstrom, the Court considered a jury instruction
stating “the law presumes that a person intends the ordinary
consequences of his voluntary acts.” Sandstrom, 442 U.S. at
512. The Court held that when given in a case in which the
defendant’s intent is an element, the instruction is unconstitu-
tional because it has “the effect of relieving the State of the
burden of proof . . . on the critical question of [the defen-
dant’s] state of mind.” Id. at 521. In Francis, the Court, rely-
ing on Sandstrom, considered instructions stating “[t]he acts
of a person of sound mind and discretion are presumed to be
the product of the person’s will, but the presumption may be
rebutted[,]” and “a person of sound mind and discretion is
presumed to intend the natural and probable consequences of
his acts[.]” Francis, 471 U.S. at 309. The Court held that

    If from all the evidence you determine to be credible you have
    a reasonable doubt whether the defendant formed any required
    mental state or had the necessary specific intent, you must find
    that he did not have such mental state or specific intent.
    At the time of the alleged offense charged in the information, you
    were [sic] instructed to presume that the defendant was sane.
Patterson, 223 F.3d at 964 (emphasis in original).
8580                  STARK v. HICKMAN
because intent was an element of the charged offense, such
instructions were unconstitutional “because a reasonable jury
could have understood the challenged portions of the jury
instruction . . . as creating a mandatory presumption that
shifted to the defendant the burden of persuasion on the cru-
cial element of intent.” Id. at 325.

   [2] Relying on Sandstrom and Francis, we declared in Pat-
terson that California’s instruction on the presumption of san-
ity was unconstitutional under clearly established federal law.
Patterson, 223 F.3d at 962-67. As we explained:

    The problem with the instruction given in this case
    is that it tells the jury to presume a mental condition
    that — depending on its definition — is crucial to
    the state’s proof beyond a reasonable doubt of an
    essential element of the crime. Under California law,
    a criminal defendant is allowed to introduce evi-
    dence of the existence of a mental disease, defect, or
    disorder as a way of showing that he did not have the
    specific intent for the crime. . . . If the jury is
    required to presume the non-existence of the very
    mental disease, defect, or disorder that prevented the
    defendant from forming the required mental state for
    [the crime], that presumption impermissibly shifts
    the burden of proof for a crucial element of the case
    from the state to the defendant. Whether the jury was
    required to presume the non-existence of a mental
    disease, defect, or disorder depends on the definition
    of sanity that a reasonable juror could have had in
    mind.

Id. at 965.

   In so ruling, we contrasted the legal definition of “sanity”
under California law with the commonly understood defini-
tion of the term. 233 F.3d at 966. Under California law,
“[s]anity is defined using a modernized version of the
                       STARK v. HICKMAN                     8581
M’Naghten Rule: a person is insane if he or she is ‘incapable
of knowing or understanding the nature and quality of his or
her act [or] of distinguishing right from wrong at the time of
the commission of the offense.’ ” Id. at 964 (quoting Cal.
Penal Code § 25(b)). By contrast, the lay definitions of “sane”
include “proceeding from a sound mind,” “rational,” “men-
tally sound,” and “able to anticipate and appraise the effect of
one’s actions.” Id. at 966 (quoting Merriam Webster’s Colle-
giate Dictionary 1035 (10th ed. 1998)). We explained that “if
a jury is instructed that a defendant must be presumed ‘sane’
— that is, ‘rational’ and ‘mentally sound,’ and ‘able to antici-
pate and appraise the effect of [his] actions,’ — a reasonable
juror could well conclude that he or she must presume that the
defendant had no [ ] mental disease, defect, or disorder. If a
juror so concludes, he or she presumes a crucial element of
the state’s proof that the defendant was guilty of [the requisite
intent].” Id.

   We also noted that the trial court did not give any special
instructions to counter the likelihood that a reasonable juror
would presume a crucial element of the state’s proof. “No-
where in his preliminary or concluding instructions did the
judge explain that the presumption of sanity was the analyti-
cal basis for the bifurcated trial; nowhere did he provide the
M’Naghten definition of insanity that the jury was asked to
presume; and nowhere did he warn the jury that ‘sane’ was
being used in something other than the conventional lay sense
that the jurors were likely to have had in mind.” Id. Under
such circumstances, we held that the guilt phase instruction on
the presumption of sanity violated the Due Process Clause of
the Fourteenth Amendment and the California Court of
Appeal’s decision upholding the conviction was contrary to,
or involved an unreasonable application of, clearly established
federal law, as determined by the Supreme Court in Sand-
strom and Francis. Id. at 966-67.

  [3] In this case, the presumption of sanity instruction given
to the jury was, in all material respects, equivalent to the
8582                    STARK v. HICKMAN
instruction at issue in Patterson. As in Patterson, the only real
issue at the guilt phase was whether petitioner had a mental
disease, defect, or disorder that precluded him from forming
the requisite specific intent: there was no dispute over what
petitioner had done, only why he had done it. Also, as in Pat-
terson, the jury was instructed at the conclusion of the guilt
phase that petitioner was presumed sane. In fact, the jury here
was instructed that petitioner was “conclusively presumed” to
be sane. As in Patterson, the jury was not advised that the
presumption of sanity was the analytical basis for the bifur-
cated trial, nor was it provided with a definition of “sane” or
“sanity” that was to be conclusively presumed or warned that
“sane” was being used in a manner other than the conven-
tional lay sense. Yet it was asked to determine whether peti-
tioner in fact had a mental defect or disorder. Consequently,
Patterson controls on the issue of whether the giving of the
instruction was error under clearly established federal law.

   [4] Moreover, the instruction read as a whole did not
explain or cure the error because the jury was not told how to
reconcile the presumption of sanity with petitioner’s attempts
to prove he lacked the requisite intent to commit murder
because of his mental condition. Thus, the potential for confu-
sion was rife, and a reasonable juror could have concluded
that he or she must presume that petitioner had no mental dis-
ease, defect, or disorder. As we noted in Patterson, “if a juror
so concludes, he or she presumes a crucial element of the
state’s proof that [petitioner] was guilty of [the requisite
intent].” Patterson, 223 F.3d at 966. The error in Patterson
was thus repeated in this case. In fact, the error here was even
more pronounced, as the charge told the jury that petitioner
was “conclusively presumed” to be sane. Thus, the California
Court of Appeal’s decision that there was no error was con-
trary to, or involved an unreasonable application of, clearly
established federal law.

  B.   The Harmless Error Standard

  It is well-established that a petitioner is not entitled to relief
under § 2254 if a constitutional error was harmless. Patterson,
                       STARK v. HICKMAN                      8583
223 F.3d at 967. Here, the California Court of Appeal con-
cluded that Patterson was “distinguishable on its facts” and
that, unlike the defendant in Patterson, “there [was] no possi-
bility that [petitioner] was prejudiced by the court’s instruc-
tion.”

   A federal court reviewing a state court decision in a habeas
corpus proceeding “ordinarily should apply the harmless error
standard . . . , namely whether the error had substantial and
injurious effect or influence in determining the jury’s ver-
dict.” California v. Roy, 519 U.S. 2, 5 (1996) (internal quota-
tions omitted). When a court applying this harmless error
standard “is in grave doubt as to the harmlessness of an error,
the habeas petitioner must win.” Id. at 5.

   In Patterson, we found that the trial court’s error in giving
the presumption of sanity instruction was not harmless. Pat-
terson, 223 F.3d at 967-68. In so holding, we observed, at the
outset, that because Patterson’s mental state was the “primary
issue” in the guilt phase, “[a]ny presumption that would have
relieved the state of its burden to prove a crucial element of
such mental state necessarily played an important role in the
jury’s ultimate determination of guilt.” Id. at 967.

   [5] Here, as in Patterson, petitioner’s mental state was the
primary issue at the guilt phase of trial. Indeed, it was the only
issue, as petitioner did not deny killing the victim. Petitioner
presented a great deal of evidence of his mental state, includ-
ing the testimony of two psychiatrists, each of whom testified
that petitioner suffered from mental impairments at the time
of the homicide. Based on this evidence, petitioner argued
that he did not have the mental state necessary for first degree
murder. The instruction that he was to be presumed “conclu-
sively sane” relieved the state of its burden to prove that men-
tal state, which was the crucial element of the crime. As in
Patterson, this error necessarily played an important role in
the jury’s ultimate determination of guilt.
8584                   STARK v. HICKMAN
   The California Court of Appeal, in finding harmless error,
relied upon the fact that unlike in Patterson, the jury here was
able to reach a verdict in the sanity phase. This, however,
does not establish that the error here was harmless. Indeed,
petitioner could be found to be legally sane, but nevertheless
be found, by a properly instructed jury, to be suffering from
a mental disease or defect such that he could not have formed
the intent necessary for first or second degree murder. As the
dissent pointed out in the California Court of Appeal’s deci-
sion, on the facts of this case, a properly instructed jury could
have convicted petitioner “of no more than voluntary or invol-
untary manslaughter.” Moreover, the jury did take some time
to make its decision here, going overnight before reaching a
verdict. Patterson does not limit relief only to those cases that
produce a hung jury in the sanity phase.

   More importantly, the trial court here set aside the jury’s
verdict of first degree murder. Finding that the facts could not
support such a verdict, the trial court reduced the conviction
to second-degree murder. This finding that there was insuffi-
cient evidence of premeditation and deliberation established
that the jury did not properly weigh the evidence and return
a legally defensible verdict. Instead, its verdict was so against
the facts that the trial court could not let it stand. If the jury
could not properly weigh the facts and correctly apply the
facts to the law, as evidenced by its first degree murder ver-
dict, one cannot conclude that the same jury was not misled
or confused by the presumption of sanity instruction.

   In finding harmless error, the Court of Appeal also found
it significant that the prosecutor and the defense counsel “vig-
orously debated” petitioner’s mental state during their final
arguments at the guilt phase of trial. This did not cure any
error, however, because the arguments were made to a jury
that was instructed to presume petitioner conclusively sane.
The lively debate took place under the wrong ground rules.
The jury weighed these arguments using the judge’s charge,
and that charge bluntly told them that petitioner was conclu-
                       STARK v. HICKMAN                     8585
sively sane, eliminating the requirement that the state prove
petitioner’s mental state.

   [6] There is simply no basis for concluding that the vigor-
ous debate of the attorneys somehow made clear to the jury
that despite the presumption of sanity, they must consider
petitioner’s attempts to prove he lacked the requisite intent to
commit murder because of his mental condition. Given the
charge, a reasonable juror could have concluded that he or she
was required to determine only whether petitioner was able to
form the requisite intent if he was sane at the time, a question
easily answered in the affirmative. As we noted in Patterson,
if a juror so concludes, he or she ignores the possibility that
petitioner had a mental disease, defect, or disorder and pre-
sumes that petitioner had the requisite intent, a crucial ele-
ment of the state’s proof. Indeed, there is nothing in the
record to suggest that the jury disregarded the presumption of
sanity charge and then went on to convict petitioner.

   [7] We therefore have “grave doubt” as to the harmlessness
of the erroneous instruction and believe that it “had substan-
tial effect or influence in determining the jury’s verdict.” Roy,
519 U.S. at 5 (internal quotation omitted). Accordingly, peti-
tioner is entitled to habeas relief because the constitutional
error of the challenged jury instruction was not harmless.

                    IV.   CONCLUSION

   [8] We conclude that the jury instruction in this case vio-
lated the Due Process Clause of the Fourteenth Amendment
and that the error was not harmless. Consequently, we
REVERSE the district court’s denial of Stark’s habeas peti-
tion, and REMAND the case to the district court with instruc-
tions to grant the writ, unless the State of California grants
Stark a new trial within a reasonable period to be set by the
district court.

  REVERSED AND REMANDED.
