                FOR PUBLICATION

  UNITED STATES COURT OF APPEALS
       FOR THE NINTH CIRCUIT


RICHARD DELMER BOYER,                     No. 13-99006
           Petitioner-Appellant,
                                           D.C. No.
               v.                     2:06-cv-07584-GAF

KEVIN CHAPPELL, Warden,
          Respondent-Appellee.             OPINION


      Appeal from the United States District Court
         for the Central District of California
        Gary A. Feess, District Judge, Presiding

                Argued and Submitted
       May 14, 2015—San Francisco, California

                    Filed July 16, 2015

   Before: Diarmuid F. O’Scannlain, Sandra S. Ikuta,
         and N. Randy Smith, Circuit Judges.

            Opinion by Judge O’Scannlain
2                      BOYER V. CHAPPELL

                           SUMMARY*


                Habeas Corpus/Death Penalty

     The panel affirmed the district court’s denial of Richard
Delmer Boyer’s habeas corpus petition challenging his two
first degree murder convictions and death sentence.

    The panel held that the state court did not unreasonably
apply clearly established Supreme Court precedent when it
determined that federal law did not require the trial court to
conduct a live evidentiary hearing to assess the reliability of
testimony that the prosecution introduced at the penalty phase
in order to prove that Boyer had committed a prior murder.
Regarding Boyer’s sufficiency of the evidence challenge to
the prior murder, in connection with which Boyer pointed to
problems with the eyewitness identification, the panel held
that fairminded jurists could disagree on the correctness of
the state court’s decision that the evidence that Boyer
committed the murder was sufficient.

    Regarding Boyer’s claim that trial counsel deficiently
failed to investigate the possibility that Boyer suffered from
organic brain damage at the guilt phase of the trial, the panel
held that it was not unreasonable for the state court to
conclude that Boyer’s counsel conducted a thorough
investigation into his mental state and that such investigation
satisfied the performance prong of Strickland v. Washington.
The panel also held that Boyer failed to demonstrate the
requisite prejudice. The panel held that the district court did

  *
    This summary constitutes no part of the opinion of the court. It has
been prepared by court staff for the convenience of the reader.
                     BOYER V. CHAPPELL                         3

not err when it denied for largely the same reasons Boyer’s
claim that trial counsel deficiently failed to investigate the
possibility that he suffered from organic brain damage at the
penalty phase.

    The panel rejected as foreclosed by precedent Boyer’s
contentions that the California death penalty is
unconstitutional by virtue of (1) the statutory scheme’s failure
to narrow adequately the class of eligible defendants and
(2) prosecutorial discretion.

    The panel declined to certify two claims relating to the
admission of testimony given pursuant to an agreement that
the testimony would be consistent with prior statements to the
police.

    Certifying three previously-uncertified claims, the panel
held that Boyer is not entitled to relief on his contentions that
the trial court erred when it sua sponte failed to instruct the
jury that unconsciousness is a complete defense and failed to
define unconsciousness, and that trial counsel provided
ineffective assistance for failure to request such instructions.
4                        BOYER V. CHAPPELL

                               COUNSEL

Lise S. Jacobson, Deputy Attorney General for the State of
California, San Diego, California, argued the cause for the
appellee the State of California. Kamala D. Harris, Attorney
General of California, filed the briefs for the appellee. With
her on the briefs were Julie L. Garland, Senior Assistant
Attorney General, and Robin Urbanski, Deputy Attorney
General, San Diego, California.

Joel Levine, Costa Mesa, California, and R. Clayton Seaman,
Prescott, Arizona, argued the cause on behalf of the
petitioner-appellant Richard Delmer Boyer and filed briefs.


                               OPINION

O’SCANNLAIN, Circuit Judge:

    We must decide whether the California Supreme Court
violated the United States Constitution in affirming a habeas
petitioner’s two first degree murder convictions and his death
sentence.

                                      I

    A California state court jury convicted Richard Delmer
Boyer of the double murder of an elderly couple, Francis and
Aileen Harbitz. After a separate penalty proceeding, the jury
returned a sentence of death.1


    1
   Boyer was tried three times for the Harbitzes’ murders. The first trial
ended when, after deliberating for 8 days, the jury failed to reach a verdict.
A second jury convicted Boyer of murdering the Harbitzes, but the
                        BOYER V. CHAPPELL                                 5

                                    A

                                     1

    At the guilt phase of trial, the prosecution showed that the
Harbitzes had been stabbed to death in their Fullerton,
California home on December 7, 1982. When their son
William Harbitz entered the home five days later, he
discovered his father’s body sitting upright against a bloody
wall in the hallway and his mother’s body covered in blood
on the living room floor. Francis had sustained approximately
24 stab wounds to the neck, chest, and back, and bled to death
because of knife wounds to the heart and aorta. Aileen had
suffered 19 stab wounds and likewise bled to death as a result
of her injuries. The Harbitzes’ residence did not show signs
of forced entry nor had it been ransacked, and there was
approximately $400 worth of cash in the home when the
bodies were discovered.

    After discovering his parents’ bodies, William mentioned
Boyer’s name to police. William had introduced Boyer to his
parents, and Boyer had done odd jobs for the Harbitzes and
borrowed money from them on occasion. William had come
to know Boyer because they had previously lived in the same
apartment complex.




California Supreme Court reversed that conviction, concluding that police
officers violated Boyer’s constitutional rights during questioning that led
to a confession. The Court determined, however, that the illegal
confession had not tainted the physical evidence, and reversed and
remanded for a new trial. The third trial, held in 1992, is the one at issue
here.
6                   BOYER V. CHAPPELL

    When police subsequently searched the residence that
Boyer maintained with his girlfriend, Cynthia Cornwell,
officers found a pair of Levi’s jeans stained with blood
consistent with Boyer’s and blood consistent with that of both
Francis and Aileen Harbitz. Officers also recovered a buck
knife, capable of inflicting the Harbitzes’ wounds and stained
with human blood, as well as the charred remains of a jacket
burned in a hibachi grill.

    John Kennedy, a key prosecution witness, testified under
a grant of immunity that he had arrived at Boyer’s residence
between 4:30 and 5:00 p.m. on the afternoon of December 7,
and that Boyer asked for a ride to his father’s house to pick
up some money. Along the way, Kennedy and Boyer stopped
to buy cocaine from a dealer Kennedy knew, using $25
Kennedy had borrowed from his brother. They then
proceeded to the home of Boyer’s father, where Boyer spent
approximately 15 minutes inside.

    Kennedy and Boyer then drove to an apartment complex
and attempted to buy marijuana, but failed. Boyer then
directed Kennedy to another apartment complex to find
“Bill.” The pair failed to locate Bill, and Boyer speculated
that Bill had moved back in with his parents. Boyer then
directed Kennedy to “some dope dealer’s house,” which
Boyer later revealed to be “Bill’s parents’ house”—that is, the
Harbitzes’ residence. Bill, of course, was William Harbitz.

    Kennedy testified that Boyer entered the Harbitzes’ home
acting normally and remained inside for about 45 minutes. He
returned, again acting normally, with a towel in hand. When
a police patrol vehicle approached, Boyer began wiping the
vehicle’s rear window with the towel and shortly thereafter
                    BOYER V. CHAPPELL                       7

admonished Kennedy to “take off calmly, not to attract any
attention.”

    As they drove away, Kennedy observed Boyer apply the
towel to his left knee. Boyer told Kennedy that he had to hurt
someone because they didn’t “have no dope” and indicated
that he had been stabbed himself. Soon after, Kennedy saw
Boyer going through two wallets. Boyer threw one of the
wallets out a window near an off ramp and put the other down
a gutter. When the pair returned to Boyer’s residence,
Kennedy observed a stab wound to Boyer’s knee. He also saw
that Boyer was wearing his buck knife, and, before he left the
residence, noted that there was blood on the open knife blade.
During the evening, Boyer told Kennedy not to tell anyone
what had happened that night.

    Cynthia Cornwell likewise testified for the prosecution
under a grant of immunity and reported that Boyer and
Kennedy had left the residence Boyer and Cornwell shared so
that Boyer could attempt to borrow money from his parents.
He had previously tried to borrow $30 from Cornwell, which
she knew to be the price of cocaine, but she had no money to
give him.

    Cornwell testified that, later that evening, when Boyer
and Kennedy returned, Boyer’s knee was bleeding and he was
limping. Boyer told Cornwell that he had been injured in a
confrontation with a loan shark. That same day, before police
officers came to their residence, Boyer asked Cornwell
whether she would wait for him if something happened.
When Cornwell asked what was wrong, Boyer said
“something about a murder” and told Cornwell “you are
going to hate me.” Cornwell admitted to burning Boyer’s
jacket on a hibachi grill.
8                   BOYER V. CHAPPELL

                              2

    For the defense, Dr. Ernest Klatte testified as an expert
witness after interviewing Boyer four times for a total of
eight and three-quarter hours. In addition to those interviews,
Dr. Klatte reviewed reports prepared by the public defender
and the Fullerton police, a forensic report prepared by the
Orange County Sheriff’s crime lab, and Boyer’s medical
records, which included indications that Boyer had suffered
two serious traffic incidents years earlier.

    Dr. Klatte related Boyer’s version of the events.
According to him, Boyer stated that he had been injecting
cocaine and drinking heavily for some time. On the day of the
murders, he drank beer in the morning and half a pint of
whiskey in the afternoon, smoked a PCP cigarette, and shared
a quarter gram of cocaine with Kennedy. He went with
Kennedy to his parents’ house in an attempt to obtain money
from his mother, but failed because his father was home. He
then attempted to find William Harbitz, but, again, failed. The
two then went to Francis and Aileen Harbitz’s home to find
out how to contact William. During the trip, he began to have
a headache and feel the effects of the PCP. Once they arrived
at the Harbitzes’ residence, Aileen Harbitz invited him into
her home, and subsequently suggested he go to the back
bedroom to talk to Francis. As he was leaving Francis’s room,
Boyer noticed a billfold and then felt very strange. Boyer felt
that he was part of the horror movie Halloween II and that
events in the house were changing speeds and items were
becoming distorted.

    Boyer’s story changed significantly over the course of his
interviews with Dr. Klatte. In his early interviews, conducted
in 1982 and 1983, Boyer stated he had no recollection of the
                     BOYER V. CHAPPELL                          9

knife or the stabbing, and indeed had no recollection at all
until he was outside in Kennedy’s car. In a 1990 interview,
however, Boyer said that he was “tripping” and hallucinated
a man coming at him with a knife. Dr. Klatte testified that
Boyer recalled having two wallets when he left the Harbitzes’
residence, and that he admitted to discarding them.

    Dr. Klatte opined, assuming Boyer told the truth about the
drugs he ingested, that Boyer might have been impulsive and
explosive on the night of the murders, and that he might have
hallucinated. He also acknowledged Boyer had an antisocial
personality and might have lied about the events in question.
Dr. Klatte testified there was a significant possibility Boyer
was malingering, and he was especially suspicious of the
hallucination claim because Boyer had not mentioned it to
him until 1990.

    Lawrence Plon, a pharmacist, also testified for the defense
that cocaine and PCP can produce excitement or catatonic
withdrawal, aggression, paranoia, hallucinations, and
delusions.

   In due course, the jury returned guilty verdicts on the two
murder charges.

                                B

    At the penalty phase of the trial, the parties stipulated that
Boyer pled guilty to committing a misdemeanor assault in
September 1980. The prosecution also presented evidence
that Boyer participated in the armed robbery of a Payless
Shoe Source store cashier in 1982, during which Boyer had
personally pulled a handgun on a store clerk, forcing her to
open the cash register and store safe.
10                  BOYER V. CHAPPELL

    In addition, the prosecution sought to prove that Boyer
murdered 75 year old Houston Compton in August 1980.
William Harbitz testified that in August, 1980, Boyer came
to his apartment door intoxicated and covered in blood and
subsequently explained he had been in a knife fight. The
prosecution’s case relied heavily on the testimony of Linda
Weissinger, who worked at a McDonald’s restaurant in
Whittier, California. She recalled a man driving a car that
matched Compton’s early 1960’s Ford Fairlane—which was
later found abandoned with a McDonald’s restaurant bag and
receipt inside—going through the McDonald’s drive-through
during the closing rush. Weissinger recalled the man had
blood on his shirt and leaned toward the passenger side of the
window as if he did not want to be seen. Despite only briefly
seeing the man, Weissinger positively identified Boyer in a
six photograph array in 1983 and testified that she was “sure”
the man she identified in 1983 and the man she had seen at
the McDonald’s were the same.

    Weissinger’s eyewitness identification was in many ways
problematic. In two live lineups, conducted in 1980 and 1981
Weissinger identified men other than Boyer as the man she
saw in the McDonald’s drive-through. In a later photographic
array, she chose someone other than Boyer before identifying
Boyer in yet another photographic array. Nonetheless, at trial,
she “explained at length why she felt sure of her choice”
when she identified Boyer in the latter photographic array
after the prior, incorrect identifications.

    Boyer presented evidence concerning the unreliability of
eyewitness reports, evidence of his difficult upbringing, and
significant testimony concerning his character in mitigation.
In any event, the jury returned a penalty of death.
                        BOYER V. CHAPPELL                             11

                                    C

    The California Supreme Court unanimously affirmed the
convictions and sentence in Boyer’s direct appeal with a
reasoned opinion, People v. Boyer, 38 Cal. 4th 412 (2006),
and the United States Supreme Court denied Boyer’s petition
for certiorari. Boyer v. California, 549 U.S. 1021 (2006). On
state habeas review, the California Supreme Court twice
denied Boyer’s petition for a writ of habeas corpus on the
merits. Boyer subsequently filed this federal habeas petition,
which the district court denied in full. Boyer timely
appealed.2

                                    II

    Boyer’s claims are governed by the Antiterrorism and
Effective Death Penalty Act of 1996 (the “AEDPA”).3 Our
statutory authority to grant habeas corpus relief to state
prisoners arises exclusively from 28 U.S.C. § 2254(d), which
states in relevant part that:

         An application for a writ of habeas corpus on
         behalf of a person in custody pursuant to the
         judgment of a State court shall not be granted


  2
    The district court had jurisdiction under 28 U.S.C. § 2254.We have
jurisdiction over the appeal from the denial of Boyer’s habeas petition
under 28 U.S.C. § 2253(a), and review the district court’s denial of a
petition for habeas corpus de novo. Walker v. Martel, 709 F.3d 925, 939
(9th Cir. 2013).
 3
   AEDPA sets forth the relevant standard of review because Boyer filed
his habeas petition in the district court in June 2010, well after AEDPA’s
effective date. Lindh v. Murphy, 521 U.S. 320, 336–37 (1997); Hedlund
v. Ryan, 750 F.3d 793, 798–99 (9th Cir. 2014).
12                   BOYER V. CHAPPELL

       with respect to any claim that was adjudicated
       on the merits in State court proceedings unless
       the adjudication of the claim—

       (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.

     “[C]learly established Federal law, as determined by the
Supreme Court of the United States . . . refers to the holdings,
as opposed to the dicta, of [the Supreme Court’s] decisions as
of the time of the relevant state-court decision.” Williams v.
Taylor, 529 U.S. 362, 412 (2000) (internal quotation marks
omitted). “‘[A]n unreasonable application of federal law is
different from an incorrect application of federal law,’”
because “[a] state court must be granted a deference and
latitude.” Harrington v. Richter, 562 U.S. 86, 101 (2011)
(quoting Williams, 529 U.S. at 410). Under such deferential
standard, “[a] state court’s determination that a claim lacks
merit precludes federal habeas relief so long as ‘fairminded
jurists could disagree’ on the correctness of the state court’s
decision.” Id. (quoting Yarborough v. Alvarado, 541 U.S.
652, 664 (2004)).

     As the Supreme Court has repeatedly been obliged to
remind us, this standard is “difficult to meet . . . because it
was meant to be.” Id. at 102 (explaining that “habeas corpus
is a guard against extreme malfunctions in the state criminal
                         BOYER V. CHAPPELL                               13

justice systems” rather than “a substitute for ordinary error
correction” (citation omitted) (internal quotation marks
omitted)). Thus, “[a]s a condition for obtaining habeas corpus
from a federal court, a state prisoner must show that the state
court’s ruling on the claim being presented in federal court
was so lacking in justification that there was an error well
understood and comprehended in existing law beyond any
possibility for fairminded disagreement.” Id. at 103.

    We apply this demanding standard to Boyer’s petition,
beginning with the four claims certified4 by the district court
followed by his five uncertified claims.

                                     III

                                     A

     Boyer first contends the district court erred when it
concluded that no clearly established federal law required the
trial court to conduct a full evidentiary hearing before
admitting evidence of the Compton murder at the penalty
phase. Boyer urges that, at least in this case, the trial court
was required to hear live testimony to determine whether the
evidence tying Boyer to the Compton murder was sufficiently
reliable to be admitted. He also suggests, even if such hearing
were not necessary, that the evidence should nonetheless have
been excluded. His argument principally relates to the
testimony of Linda Weissinger.



  4
    “Before an appeal may be entertained, a prisoner who was denied
habeas relief in the district court must first seek and obtain a [certificate
of appealability].” Miller–El v. Cockrell, 537 U.S. 322, 335–36 (2003);
see 28 U.S.C. § 2253(c).
14                     BOYER V. CHAPPELL

                                   1

    On direct review, the California Supreme Court held that
no error had occurred in the trial court’s failure to conduct a
live evidentiary hearing. Although not specifically stating that
no hearing was required, it “independently conclude[d]” that
“Weissinger’s identification testimony at trial was not
excludable . . . and [] the evidence that defendant murdered
Compton was legally sufficient for consideration by the
penalty jury.” Boyer, 38 Cal. 4th at 477. On federal habeas
review, the district court noted that, while the trial court had
not heard live evidence regarding Weissinger’s testimony, it
had conducted three hearings on the matter. The district court
also agreed that Boyer had identified no clearly established
federal law entitling him to an evidentiary hearing.

    Boyer relies principally on People v. Phillips, 41 Cal. 3d
29 (1985). There, the California Supreme Court explained
that, before allowing the introduction of evidence concerning
prior uncharged offenses, “it may be advisable for the trial
court to conduct a preliminary inquiry before the penalty
phase to determine whether there is substantial evidence to
prove each element of the other criminal activity” at issue. Id.
at 72 n.25. Phillips, of course, is not a Supreme Court case
and so does not represent “clearly established Federal law,”
which embodies “the governing legal principle or principles
set forth by the Supreme Court at the time the state court
render[ed] its decision.” Lockyer v. Andrade, 538 U.S. 63,
71–72 (2003).5


  5
    At oral argument, counsel for Boyer contended that our opinion in
Hurles v. Ryan, 752 F.3d 768 (9th Cir. 2014), stands for the proposition
that, when there has been a prima facie showing of a constitutional
violation and a request for an evidentiary hearing has been made but no
                         BOYER V. CHAPPELL                               15

     Boyer, however, points to three Supreme Court cases he
contends create clearly established federal law requiring the
trial court to conduct a Phillips hearing. The first, Neil v.
Biggers, 409 U.S. 188 (1972), is a pre-AEDPA case involving
whether a rape victim’s identification of her attacker
comported with due process. Rather than identifying the
accused in a lineup, police showed the victim the accused
alone because no suitable lineup could be constructed from
the occupants of the city jail or the city juvenile home. Id. at
195. The Biggers Court concluded such identification did not
violate due process, and held the “central question” was
“whether under the totality of the circumstances the
identification was reliable even though the confrontation
procedure was suggestive.” Id. at 199 (internal quotation
marks omitted). It did not address what type of evidentiary
hearing the trial court needed to conduct in determining
whether the eyewitness identification could be put before the
jury.

    Boyer also relies on Manson v. Brathwaite, 432 U.S. 98
(1977). That case largely followed Biggers, holding
“reliability is the linchpin in determining the admissibility of
identification testimony” and concluding “[t]he factors to be
considered [we]re set out in Biggers.” Id. at 114. Like


such hearing has occurred, state court determinations are, in general, owed
less deference on habeas review. Such contention is incorrect.

     In Hurles, we evaluated the Supreme Court’s clearly established
caselaw regarding judicial bias and determined that, based on the facts of
that case, the state court’s denial of Hurles’s judicial bias claim “rest[ed]
on an unreasonable determination of the facts.” Id. at 790. Our holding in
that case does not affect the level of deference generally owed to state
court determinations under § 2254(d). Boyer’s claims are governed by the
stringent AEDPA standard set forth by many Supreme Court cases.
16                  BOYER V. CHAPPELL

Biggers, Manson contains no discussion regarding when a
trial court must conduct a live evidentiary hearing before
allowing eyewitness testimony. In sum, if Biggers and
Brathwaite relate to Boyer’s claim at all, they are of no help
to him.

    Boyer next points to Watkins v. Sowders, 449 U.S. 341
(1981). There, the Court addressed whether a “trial court is
constitutionally compelled to conduct a hearing outside the
presence of the jury whenever a defendant contends that a
witness’ identification of him was arrived at improperly.” Id.
at 342. The Watkins Court concluded the Constitution
required no such hearing, explaining “[a] judicial
determination outside the presence of the jury of the
admissibility of identification evidence may often be
advisable . . . [b]ut it does not follow that the Constitution
requires a per se rule compelling such a procedure in every
case.” Id. at 349. It noted “the proper evaluation of evidence
under the instructions of the trial judge is the very task our
system must assume juries can perform,” id. at 347, but also
suggested that “[i]n some circumstances” a hearing outside
the presence of a jury to determine the admissibility of
evidence “may be constitutionally necessary,” id. at 349.
Watkins, though, never elaborates. Id. Moreover, the Supreme
Court did not squarely hold that an evidentiary hearing is ever
required in any particular circumstances—indeed, it did not
provide any guidance as to when such circumstances might
arise. A state court could reasonably conclude that Watkins
does not constitute clearly established federal law that could
entitle Boyer to relief.

    More recently, in Perry v. New Hampshire, 132 S. Ct.
716, 723 (2012), the Court examined when a trial court is
obliged to evaluate allegedly unreliable “eyewitness
                    BOYER V. CHAPPELL                       17

identification made under suggestive circumstances not
arranged by the police” before such identification may be
presented to a jury. The Perry Court held that “[o]nly when
evidence is so extremely unfair that its admission violates
fundamental conceptions of justice . . . have we imposed a
constraint tied to the Due Process Clause.” Id. (citation
omitted) (internal quotation marks omitted). It explained “the
Due Process Clause does not require a preliminary judicial
inquiry into the reliability of an eyewitness identification
when the identification was not procured under unnecessarily
suggestive circumstances arranged by law enforcement.” Id.
at 730. While Boyer contends Weissinger’s testimony was
unreliable in many respects, he does not contend such
unreliability stems from unnecessarily suggestive
circumstances arranged by law enforcement. Thus, Perry
likewise does not entitle Boyer to relief.

    We therefore conclude that the state court did not
unreasonably apply clearly established Supreme Court
precedent when it determined that federal law did not require
a live evidentiary hearing to assess the reliability of Lisa
Weissinger’s testimony.

                              2

    Boyer further presses the related argument that evidence
of the Compton homicide should have been excluded as
insufficient and unreliable. His contention takes the form of
a sufficiency of the evidence claim under Jackson v. Virginia,
443 U.S. 307, 318 (1979) (holding that “the critical inquiry
on review of the sufficiency of the evidence . . . [is] whether
the record evidence could reasonably support a finding of
guilt beyond a reasonable doubt”).
18                   BOYER V. CHAPPELL

    Under Jackson, “evidence is sufficient to support a
conviction so long as ‘after viewing the evidence in the light
most favorable to the prosecution, any rational trier of fact
could have found the essential elements of the crime beyond
a reasonable doubt.’” Cavazos v. Smith, 132 S. Ct. 2, 6 (2011)
(per curiam) (quoting Jackson, 443 U.S. at 319). On habeas
review, “the deference to state court decisions required by
§ 2254(d)” combines with “the state court’s already
deferential review” of sufficiency of the evidence claims. Id.;
see Juan H. v. Allen, 408 F.3d 1262, 1274 (9th Cir. 2005)
(recognizing AEDPA and Jackson combine to create double
deference).

    To buttress his argument, Boyer points to several
problems with Weissinger’s identification. For example, in
the two live lineups, Weissinger identified men other than
Boyer. She also identified men other than Boyer in
photographic lineups before finally choosing Boyer in a
photographic array in 1983.

      In deciding no error had occurred, the California Supreme
Court explained that “[i]dentification of the defendant by a
single eyewitness may be sufficient to prove the defendant’s
identity as the perpetrator of a crime” and concluded that “the
evidence that [Boyer] murdered Compton was sufficient.”
Boyer, 38 Cal. 4th at 480. It relied upon the fact that
“Weissinger readily testified that, after careful consideration,
she made a positive identification of defendant from a photo
array as the McDonald’s customer she saw on the night of the
Compton murder,” and she “explained at length why she felt
sure of her choice.” Id. The Court further explained Boyer’s
counsel had “a full opportunity to cross-examine Weissinger
. . . about all aspects of the identification process” and that
“William Harbitz provided some independent evidence of
                    BOYER V. CHAPPELL                        19

defendant’s identity as Compton’s killer” by describing the
August 1980 incident when Boyer informed Harbitz that he
had been in a knife fight while wearing a bloody shirt. Id. at
481.

    In light of these facts and the applicable standard of
review, we conclude that, at the very least, “fairminded jurists
could disagree” on the correctness of the state court’s
decision. Richter, 562 U.S. at 101 (internal quotation marks
omitted). And, as the Supreme Court has repeatedly
emphasized, that is all that is required.

                               B

    Boyer next contends the district court erred when it
denied his claim that his trial counsel deficiently failed to
investigate the possibility that Boyer suffered from organic
brain damage at the guilt phase of the trial. Based on testing
performed in 2001 by Dr. Natasha Khazanov during post-
conviction proceedings, Boyer contends he suffered from
severe organic brain damage and, moreover, that counsel’s
failure to investigate such possibility amounted to ineffective
assistance of counsel under Strickland v. Washington, 466
U.S. 668 (1984). Boyer contends evidence of organic brain
damage would have bolstered defenses of unconsciousness,
insanity, and unconsciousness due to intoxication.

    In order to succeed on a Strickland claim, a claimant must
“show that counsel’s performance was deficient” and that
“the deficient performance prejudiced the defense.” Id. at
687. To demonstrate deficient performance Boyer “must
show that counsel’s representation fell below an objective
standard of reasonableness,” and, in making that
determination, courts must “indulge a strong presumption that
20                  BOYER V. CHAPPELL

counsel’s conduct falls within the wide range of reasonable
professional assistance.” Id. at 688–89. In order to show
prejudice, Boyer must show “there is a reasonable probability
that, but for counsel’s unprofessional errors, the result of the
proceeding would have been different.” Id. at 694. We can
only grant relief based on counsel’s alleged ineffectiveness if
both criteria have been met.

    Because Boyer brings his Strickland claim on federal
habeas, he must surmount an even higher bar. On habeas
review, we examine whether the state court reasonably
applied Strickland. “The standards created by Strickland and
§ 2254(d) are both highly deferential,” giving rise to
“doubl[e]” deference. Richter, 562 U.S. at 105 (internal
quotation marks omitted). “[T]he question is not whether
counsel’s actions were reasonable. The question is whether
there is any reasonable argument that counsel satisfied
Strickland’s deferential standard.” Id. (emphasis added).

                               1

    Boyer’s claim turns primarily on his counsel’s alleged
failure to investigate further the diagnosis by Dr. Kenneth
Nudleman. One of the several experts to evaluate Boyer’s
mental state, Dr. Nudleman performed an MRI on Boyer’s
brain, the results of which were normal. However, an
electroencephalogram showed abnormalities, and Dr.
Nudleman recommended neuropsychometric testing and a
PET scan. No such testing appears to have been performed,
                        BOYER V. CHAPPELL                               21

and Boyer alleges this failure to secure such testing amounted
to ineffective assistance of counsel.6

    Boyer’s argument fails, however, to credit the extensive
investigation his counsel performed into his mental
state—indeed, Boyer was evaluated by numerous mental
health experts in preparation for his multiple trials. In
addition to Dr. Klatte and Dr. Plon, Boyer was evaluated by
Dr. Ronald Siegel, a psychopharmacologist, who testified at
Boyer’s second trial that Boyer could have had a flashback,
but provided no indication that he suffered from organic brain
damage. Similarly, Dr. Jonathan Salk, a psychiatrist,
evaluated Boyer for signs of post traumatic stress disorder,
but made no mention of the possibility of organic brain
damage.

    Two court-appointed physicians also evaluated Boyer.
One, Dr. William Loomis, a psychiatrist and neurologist,
concluded Boyer was sane at the time of the crime and at the
time of examination. Dr. Loomis did not credit the possibility
of organic brain damage. Dr. Edward Kaufman, a psychiatrist
and assistant professor of psychology, concluded that Boyer

 6
    Boyer places great weight on a declaration by his trial counsel stating
that he did not make a tactical decision when he failed pursue Dr.
Nudleman’s recommendations. In short, Boyer argues that the record
before the state courts will only support the conclusion that counsel did
not make such a tactical decision. The Supreme Court, however, has
repeatedly cautioned that “[a]fter an adverse verdict at trial even the most
experienced counsel may find it difficult to resist asking whether a
different strategy might have been better, and, in the course of that
reflection, to magnify their own responsibility for an unfavorable
outcome.” Richter, 562 U.S. at 109. “Strickland . . . calls for an inquiry
into the objective reasonableness of counsel’s performance, not counsel’s
subjective state of mind.” Id. at 110. The declaration, therefore, cannot
bear the weight Boyer ascribes to it.
22                   BOYER V. CHAPPELL

suffered from an antisocial personality and from chronic
substance abuse. Dr. Kaufman thoroughly considered Boyer’s
medical history and found that it was unlikely Boyer suffered
from a hallucination during the Harbitzes’ murders. While Dr.
Kaufman was aware Boyer had been in a car accident in 1976
and had subsequently undergone a neurological examination,
Dr. Kaufman did not suggest a likelihood of organic brain
damage. Rather, Dr. Kaufman stated that neurological illness
was unlikely and could best be ruled out by diagnostic
testing.

    We have previously denied claims relating to alleged
failures to investigate organic brain damage in similar
circumstances. For example, in Earp v. Cullen, we held that
the petitioner had failed to demonstrate that his trial counsel’s
conduct fell below Strickland’s standard on AEDPA review
where medical experts “concluded that [the petitioner] had
deficits in processing speed and working memory that were
consistent with organic brain damage.” 623 F.3d 1065, 1076
(9th Cir. 2010). We concluded counsel was not ineffective in
large part because he had pursued evidence related to Earp’s
mental state and abilities at the time of the trial, and because
a psychologist who examined Earp concluded instead that
Earp was a sociopath. Id. Moreover, we held that the fact that
Earp could produce an expert eleven years after the trial “who
is willing to opine that he had organic brain damage at the
time of his trial does not impact the ultimate determination of
whether Earp’s trial counsel insufficiently investigated that
possibility.” Id.

    We reached a similar conclusion in West v. Ryan, where
we held petitioner’s counsel had not fallen below the
Strickland standard by failing to follow up on a medical
expert’s conclusion that “cognitive impairment could not be
                        BOYER V. CHAPPELL                              23

‘ruled out’ absent further testing.” 608 F.3d 477, 488–89 (9th
Cir 2010). Based on the totality of the circumstances, that
remark was “not the kind of powerful mitigating evidence
sufficient to overcome Strickland’s presumption that counsel
acted reasonably in declining to investigate further the
possibility . . . [of] cognitive impairment.” Id. at 489 (internal
quotation marks omitted).

    In Leavitt v. Arave, 646 F.3d 605, 609–10 (9th Cir.
2011), we again found that trial counsel satisfied Strickland
under similar circumstances. There, the petitioner argued trial
counsel could not have made a reasonable strategic decision
not to investigate further a CT scan that revealed cortical
atrophy and suggested a possibility of disease. Id. While the
petitioner’s doctor “may have found some evidence
suggesting a cognitive impairment,” he “ultimately concluded
that the results . . . were more consistent with a diagnosis of
a personality disorder,” and we held that no additional testing
was required to satisfy Strickland. Id. at 609.

    Confronted with multiple medical evaluations, none of
which identified organic brain damage, Boyer’s trial counsel
could justifiably have concluded that further investigation
was unnecessary. As in Earp, West, and Leavitt, we are
satisfied that it was not unreasonable for the California
Supreme Court to conclude that Boyer’s counsel conducted
a thorough investigation into his mental state and that such
investigation satisfied the performance prong of Strickland,
especially in light of the double deference owed that
conclusion on federal habeas review.7


 7
   Boyer also relies on Wiggins v. Smith, 539 U.S. 510 (2003), a case in
which the Supreme Court held that trial counsel’s cursory investigation
into mitigating circumstances related to the petitioner’s life history fell
24                      BOYER V. CHAPPELL

                                    2

    Moreover, Boyer has failed to demonstrate the prejudice
required to mount successfully a Strickland claim. In order to
show prejudice, “[t]he defendant must show that there is a
reasonable probability that, but for counsel’s unprofessional
errors, the result of the proceeding would have been
different.” Cullen v. Pinholster, 131 S. Ct. 1388, 1403 (2011)
(quoting Strickland, 466 U.S. at 694). “A reasonable
probability is a probability sufficient to undermine confidence
in the outcome.” Id. (internal quotation marks omitted). A
substantial likelihood of a different result, as opposed to a
mere conceivable possibility, is required. Id.

    In light of the compelling evidence adduced against him
at trial, Boyer cannot show that there is a reasonable
probability of a different result had his counsel pursued
additional evidence of organic brain damage. The evidence
at trial discredits the idea that Boyer suffered from a
hallucination or was otherwise unconscious or insane when
he murdered the Harbitzes. For example, as the California
Supreme Court noted, Boyer appeared “mentally normal at all
times during the evening” of the murder. Boyer, 38 Cal. 4th
at 470–71. He tried to deflect suspicion when he saw a police
patrol car and told Kennedy to drive away without attracting
attention. Id. at 470. He disposed of the Harbitzes’ wallets,
did not tell either Kennedy or Cornwell about the alleged


below Strickland’s standard. That case is easily distinguishable on the
facts. There, counsel performed no investigation into the petitioner’s life
history beyond reviewing a one page summary contained in a presentence
investigation report and unrelated department of social services records.
Id. at 523–24. Here, as discussed, Boyer’s counsel conducted a detailed
investigation into his mental state.
                    BOYER V. CHAPPELL                       25

hallucination, and lied to both Kennedy and Cornwell to
explain his knife wounds. Id. at 421–22.

    In addition, Dr. Klatte and Dr. Kaufman, experts obtained
by the defense and the trial court respectively, expressed
skepticism regarding Boyer’s story. Id. at 459–60, 470. Dr.
Klatte’s testimony, in particular, seriously undermined
Boyer’s claim he was unconscious or insane at the time of the
murders when he revealed that Boyer had not informed him
of the hallucination until years after the murders took place.

     Thus, even if Boyer’s counsel had been ineffective for
failing to investigate further the possibility of organic brain
damage, Boyer has failed to show there was a “reasonable
probability that, but for counsel’s unprofessional errors, the
result of the proceeding would have been different.”
Strickland, 466 U.S. at 694.

                              C

    Boyer next contends the district court erred when it
denied his claim that his trial counsel deficiently failed to
investigate the possibility Boyer suffered from organic brain
damage at the penalty phase of the trial. Boyer marshals
largely the same legal arguments and facts as he employed to
support his contention that counsel provided ineffective
assistance of counsel at the guilt phase of the trial.

    We therefore conclude that the district court did not err
when it denied Boyer’s claim for largely the same reasons. As
we concluded in Earp, West, and Leavitt, and for the reasons
we have already explained, we conclude that trial counsel
could justifiably have decided that further investigation into
the possibility of organic brain damage was unnecessary in
26                  BOYER V. CHAPPELL

light of the many experts who investigated Boyer’s mental
state but made no mention of such condition. Moreover, the
reasons we have already identified demonstrate Boyer
suffered no prejudice, even supposing that his counsel’s
investigation was deficient. Evidence suggested that Boyer
was in search of money when he entered the Harbitzes’ home,
that he took the Harbitzes’ wallets and later hid them, that he
attempted to avoid arousing suspicion as he left the
Harbitzes’ home, and that he attempted to mislead both
Kennedy and Cornwell about the cause of injuries he
sustained while inside the home. Moreover, Boyer’s own
experts doubted his proffered explanation of events, in part
because that explanation changed significantly over time. We
therefore conclude that Boyer has failed to demonstrate that
counsel’s alleged deficient performance in failing to
investigate adequately the possibility of organic brain damage
prejudiced him at the penalty phase.

                              D

    Finally, Boyer contends the district court erred when it
concluded California’s death penalty procedures do not
violate the Fifth, Eighth, and Fourteenth Amendments to the
United States Constitution. Boyer argues both that the State’s
statutory scheme fails to narrow adequately the class of
defendants eligible for the death penalty, and that
prosecutorial discretion to seek the death penalty renders such
penalty unconstitutional.

                              1

    We have, on multiple occasions, already rejected the
claim that California’s death penalty scheme fails to narrow
sufficiently the class of defendants eligible for such
                     BOYER V. CHAPPELL                        27

punishment. In Mayfield v. Woodford, 270 F.3d 915, 924 (9th
Cir. 2001) (en banc) we, sitting en banc, held that “[a]
reasonable jurist could not debate . . . that the 1978 California
statute, which narrowed the class of death-eligible defendants
at both the guilt and penalty phases, was constitutional.”
Likewise, in Karis v. Calderon, 283 F.3d 1117, 1141 n.11
(9th Cir. 2002), we expressly “reject[ed] Karis’ argument that
the [California statutory] scheme does not adequately narrow
the class of persons eligible for the death penalty,” explaining
that “[t]he California statute satisfies the narrowing
requirement” set forth by the Supreme Court.

    We therefore conclude that precedent forecloses Boyer’s
claim that California’s death penalty scheme is
unconstitutional.

                               2

    Further, Boyer claims that prosecutorial discretion to seek
the death penalty renders it unconstitutional. This argument
has likewise been repeatedly rejected by the Supreme Court
and our Court. See Gregg v. Georgia, 428 U.S. 153, 199
(1976) (rejecting claim that Georgia’s death penalty scheme
was unconstitutional because “the state prosecutor has
unfettered authority to select those persons whom he wishes
to prosecute for a capital offense and to plea bargain with
them”); Proffitt v. Florida, 428 U.S. 242, 254 (1976) (holding
argument that “the prosecutor’s decision whether to charge a
capital offense in the first place” rendered Florida’s death
penalty unconstitutional represented “a fundamental
misinterpretation” of Supreme Court precedent and rejecting
such argument); United States v. Mitchell, 502 F.3d 931, 982
(9th Cir. 2007) (explaining claim that prosecutorial discretion
28                  BOYER V. CHAPPELL

rendered death penalty unconstitutional was foreclosed). We
again reject it.

                              IV

    Boyer renews his request for a certificate of appealability
as to the five claims for which the district court denied such
certificate. Under 28 U.S.C. § 2253(c)(2), “[a] certificate of
appealability may issue . . . only if the applicant has made a
substantial showing of the denial of a constitutional right.”
This standard is satisfied when “‘reasonable jurists could
debate whether (or, for that matter, agree that) the petition
should have been resolved in a different manner or that the
issues presented were adequate to deserve encouragement to
proceed further.’” Miller–El, 537 U.S. at 336 (quoting Slack
v. McDaniel, 529 U.S. 473, 484 (2000) (citation omitted)
(internal quotation marks omitted)); see also Shoemaker v.
Taylor, 730 F.3d 778, 790 (9th Cir. 2013) (“A certificate of
appealability should issue if ‘reasonable jurists could debate
whether’ (1) the district court’s assessment of the claim was
debatable or wrong; or (2) the issue presented is ‘adequate to
deserve encouragement to proceed further.’” (quoting Slack,
529 U.S. at 484)). In determining whether the substantial
showing requirement is satisfied, we must not perform a full
consideration of the merits. Miller–El, 537 U.S. at 336 (“This
threshold inquiry does not require full consideration of the
factual or legal bases adduced in support of the claims. In
fact, the statute forbids it.”).

                              A

     In Boyer’s first uncertified claim, he contends that the
trial court erred in failing to exclude John Kennedy’s
testimony because such testimony was given pursuant to an
                     BOYER V. CHAPPELL                        29

agreement which stated that Kennedy’s testimony would be
consistent with certain prior statements made to police.
Because Boyer has not identified any clearly established
Supreme Court precedent suggesting that such a clause
violates due process or any other constitutional provision, we
decline to grant a certificate of appealability on this claim.
See also Cook v. Schriro, 538 F.3d 1000, 1017 (9th Cir. 2008)
(“[T]here is no Supreme Court case law establishing that
consistency clauses violate due process or any other
constitutional provision.”). We also deny certification of
Boyer’s second claim, in which he contends that his trial
counsel provided ineffective assistance of counsel by failing
to object to Kennedy’s testimony based on the same
inadmissability concerns. Because any such objection would
have been fruitless, Boyer’s counsel could not have rendered
ineffective assistance of counsel by failing to make it.

                               B

     In his third, fourth, and fifth uncertified claims, Boyer
contends that the trial court erred when it sua sponte failed to
instruct the jury that unconsciousness is a complete defense
and failed to define unconsciousness. He also contends that
his trial counsel provided ineffective assistance of counsel for
failure to request such instructions. We evaluate these claims
together because they arise from closely related jury
instructions, and grant a certificate of appealability on each of
them.

                               1

   On direct appeal, the California Supreme Court declined
to address “whether the trial court erred by failing, sua
sponte, to instruct on the complete defense of
30                   BOYER V. CHAPPELL

unconsciousness” and “[found] that if error occurred, it was
harmless by any applicable standard.” Boyer, 38 Cal. 4th at
470.

    Boyer cites two Supreme Court cases for the proposition
that the trial court violated clearly established federal law
when it failed to instruct the jury that unconsciousness is a
complete defense. The first, Chambers v. Mississippi,
410 U.S. 284, 294 (1973), merely held that “[t]he right of an
accused in a criminal trial to due process is, in essence, the
right to a fair opportunity to defend against the State’s
accusations.” But the Court went on to apply that principle in
the context of the opportunity to call witnesses to testify
rather than a trial court’s obligations when instructing a jury.
See id. at 295–303. The second case cited by Boyer is equally
unhelpful. In Rose v. Clark, 478 U.S. 570, 577–79 (1986), the
Court held only that an erroneous jury instruction regarding
malice was subject to harmless error review. In short, Boyer
has failed to present, nor have we identified, any Supreme
Court precedent stating clearly established federal law that
entitles Boyer to the jury instruction at issue. Boyer’s reliance
on these cases is therefore misplaced.

    Moreover, even if clearly established Supreme Court
precedent required such instruction, Boyer would still not be
entitled to relief. The question before us is “whether the ailing
instruction by itself so infected the entire trial that the
resulting conviction violates due process.” Estelle v.
McGuire, 502 U.S. 62, 72 (1991). “The burden on the habeas
petitioner is ‘especially heavy’ where, as here, the alleged
error involves the failure to give an instruction.” Clark v.
Brown, 450 F.3d 898, 904 (9th Cir. 2006) (quoting Hendricks
v. Vasquez, 974 F.2d 1099, 1106 (9th Cir. 1992)).
                    BOYER V. CHAPPELL                       31

    Applying that standard, ample evidence supports the
California Supreme Court’s determination that any error was
harmless, including Boyer’s rational appearance throughout
the day, his goal-directed actions following the murder
(including instructing Kennedy to avoid police and disposing
of the Harbitzes’ wallets), the lack of evidence that Boyer
told Kennedy or Cornwell about his hallucination, and his
own experts’ skepticism regarding the hallucination claim.
Boyer, 38 Cal. 4th at 470–71.

                              2

    Boyer next contends that the trial court erred when it
failed to provide a jury instruction defining unconsciousness,
and that such failure rendered his trial fundamentally unfair.

    Boyer’s claim suffers from the same deficiencies that
undermine his contention that the trial court should have
instructed the jury that unconsiousness is a complete defense.
Specifically, he has failed to identify any clearly established
Supreme Court precedent that would entitle him to have the
state court sua sponte give the additional instruction he
requests. Moreover, Boyer has failed to bear the especially
heavy burden placed on him to demonstrate that the lack of
the requested instruction so infected the trial that his Due
Process rights were violated. Estelle, 502 U.S. at 72; Clark,
450 F.3d at 904.

    Further, we agree with the California Supreme Court, that
in light of the instructions given by the trial court, “[n]o
reasonable juror could fail to understand . . . that one can
perform acts while unconscious.” Boyer, 38 Cal. 4th at 472.
The California Supreme Court noted that the jury instruction
given on unconsciousness by voluntary intoxication stated
32                   BOYER V. CHAPPELL

that an individual who, “‘while unconscious as a result of
voluntary intoxication, killed another human being without an
intent to kill and without malice aforethought’ is guilty of
involuntary manslaughter.” Id. (quoting CALJIC No. 8.47).
Moreover, an individual who becomes voluntarily intoxicated
“to the point of unconsciousness . . . assumes the risk that
while unconscious [he] [she] will commit acts dangerous to
human life or safety.” Id. (quoting CALJIC No. 8.47)
(alterations in original).

                               3

    Finally, Boyer contends that his counsel was ineffective
under Strickland for failing to request jury instructions related
to unconsciousness. As noted above, the jury was presented
with numerous instructions explaining the effect of Boyer’s
alleged unconsciousness and thus a reasonable juror would
have understood everything necessary to evaluate that theory
of Boyer’s defense. See United States v. Chambers, 918 F.2d
1455, 1462 (9th Cir. 1990). Moreover, even if that were not
so, any error was harmless. As we have already detailed at
length, should any error have occurred, Boyer has failed to
demonstrate such error was prejudicial. See, supra, Part
III.B.2; Boyer, 38 Cal. 4th at 470–471.

                               V

   For the foregoing reasons, the judgment of the district
court is

     AFFIRMED.
