                  FOR PUBLICATION
 UNITED STATES COURT OF APPEALS
      FOR THE NINTH CIRCUIT

STEVE COX,                                  No. 06-15106
               Petitioner-Appellant,
                 v.                           D.C. No.
                                           CV-98-00482-PMP
FRANKIE SUE   DEL PAPA,
                                              OPINION
              Respondent-Appellee.
                                       
      Appeal from the United States District Court
               for the District of Nevada
        Philip M. Pro, District Judge, Presiding

                 Argued and Submitted
       August 15, 2007—San Francisco, California

                  Filed September 4, 2008

 Before: Diarmuid F. O’Scannlain, Michael Daly Hawkins,
        and Kim McLane Wardlaw, Circuit Judges.

               Opinion by Judge O’Scannlain




                            12225
                      COX v. DEL PAPA                 12229


                        COUNSEL

Paul G. Turner, Assistant Federal Public Defender, Las
Vegas, Nevada, argued the cause for the petitioner-appellant
12230                 COX v. DEL PAPA
and filed briefs; Franny A. Forsman, Federal Public Defender
and Danice Arbor Johnson, Research & Writing Specialist,
Las Vegas, Nevada, were on the briefs.

David Neidert, Senior Deputy Attorney General, Las Vegas,
Nevada, argued the cause for the respondents-appellees; Cath-
erine Cortez Masto, Attorney General and Dennis C. Wilson,
Deputy Attorney General, filed and were on the brief.


                         OPINION

O’SCANNLAIN, Circuit Judge:

   We must decide whether the Constitution requires that a
trial court conduct a sua sponte examination of a criminal
defendant’s Miranda waiver when his competency to stand
trial has been raised.

                              I

   Sometime in March 1990, Steve Cox left Vallejo, Califor-
nia, headed to Tennessee in a 30-year old truck with a
football-sized hole in the windshield. He carried approxi-
mately $16,000 in cash. Upon arrival in Las Vegas, Nevada,
Cox stopped to repair his ailing truck. While there, he became
involved with Carita Wilson, a prostitute with an extensive
criminal record. Cox checked into the Days Inn Motel in
North Las Vegas, accompanied by Wilson. The next day, on
March 22, 1990, hotel employees found Wilson’s strangled
body in the hotel room. When police arrived, they noted that
Wilson had a television cord wrapped around her wrist and a
towel around her throat.

   Later that day, Officers Scott Tyman and M. L. Ransom of
the Arizona Highway Patrol arrested Cox about nine miles
from Winslow, Arizona. Officer Tyman told Cox that he was
                           COX v. DEL PAPA                         12231
being “detained for committing the crime of being a fugitive
of justice” and read him his Miranda rights from a
Department-issued card.1 Cox “acknowledge[d] that he under-
stood the Miranda warnings.” Tyman asked him whether he
knew why he was being arrested, and Cox stated that he “was
framed, that it was self-defense.” Ransom “asked him whether
he killed anybody,” whereupon “[Cox] said that the girl had
come to him with fangs and fingernails and that he only
choked her around the neck long enough to subdue her, to get
away.” Cox “talked a lot” for the next 10 minutes. The offi-
cers then took him to the county jail and documented his
property, which included roughly $8,000 in cash.

   A week later, Detectives Bruce Scroggin and Jack Larason
of the North Las Vegas Police Department went to Arizona to
interview Cox. They “advised Mr. Cox of his rights and he
chose not to talk to [them].” Cox also made clear that he “did
not wish to return or come willingly back [to Nevada].” After
obtaining a governor’s warrant to bring Cox back to Nevada,
Detective Scroggin returned to Arizona in May 1990, this
time joined by Detective A. Calvert. Prior to departing with
Cox, Scroggin read Cox his Miranda rights. Again, Cox
acknowledged that he understood his rights.

  Detective Scroggin also told Cox that he and Detective Cal-
vert “were not going to question him about the incident at all”
during the ride back to Las Vegas. However, Cox decided to
speak spontaneously “for almost 10 hours straight about
everything under the sun.”2 Among other things, Cox told the
detectives that Wilson had emerged from the bathroom with
her hair dripping wet and wrapped in a towel, that she had
  1
     The account presented here comes from the testimony of Officer
Tyman, and Cox does not dispute its truth. Officer Tyman testified with
reference to a report that he wrote “the same night [Cox] was arrested,”
when the events were “very fresh in [his] memory.”
   2
     Cox does not argue that the officers asked him questions or pressured
him to speak.
12232                   COX v. DEL PAPA
“flipped out,” and that Cox had to remove the towel and
restrain her, causing her to pass out. When she awoke, she
again “flipped out” and he again had to restrain her because
she was “acting bizarre and devilish.” She passed out again,
and after he restrained her a third time, she did not regain con-
sciousness. At this point, he checked her pulse, found it to be
“racing at 90 miles an hour and [ ] felt she was going to die,”
and left the hotel “hoping someone would find her and take
care of her.”

                               A

   On April 11, 1990, state prosecutors in Clark County,
Nevada, charged Cox with murder with use of a deadly
weapon. Before trial, several psychiatrists examined Cox to
determine whether he was competent to stand trial. Psychia-
trist Dr. Franklin Master explained that he “did not get a feel-
ing of psychosis, but rather felt that [Cox] was attempting to
malinger because of the seriousness of the charge against
him.” And although Dr. Master noted “the possibility that this
individual’s behavior on the night in question might well have
been influenced by his use of cocaine,” and “the possibility
that even now there could be residual effects of heavy cocaine
use,” he concluded that Cox was not “currently [ ] under the
influence of any substance,” and was “competent to assist
counsel.”

   In a report dated several months later, psychiatrist Dr. Wil-
liam O’Gorman recorded Cox’s family history and assessed
his mental state. He found that Cox exhibited “a moderate
degree of repression and suppression,” signs of “a personality
disorder of a mixed type with noticeable paranoid trends and
some preoccupation, overcompensation and some immaturity
with impulsiveness in his relationships with people.” How-
ever, Dr. O’Gorman discerned “no true disorganization of
personality,” noted that Cox “denie[d] being addicted to
cocaine,” and concluded that “Cox [wa]s knowledgeable to
                           COX v. DEL PAPA                         12233
the events that transpired regarding the present charge and
c[ould] assist his attorney in his own defense if he so desire[d].”3

   Two other psychiatrists who examined Cox later on dis-
agreed, however, and opined that Cox was not competent to
stand trial. Dr. Jack Jurasky wrote that Cox was “intelligent,
cooperative, fluent, and articulate,” but “suffer[ed] from a
psychotic process called ‘Delusional Disorder’ as manifested
by florid paranoid and grandiose delusions about his impor-
tance.” He stated that he believed Cox should be considered
“ ‘Guilty But Mentally Ill’ ” but not “Not Guilty by Reason
of Insanity” because Cox “certainly comprehend[ed] the
nature and quality of the charges against him and respond[ed]
to those charges relevantly in the manner by which he
denie[d] them.”

  Less than a month later, Dr. William Pike evaluated Cox
and rendered the following diagnosis: “Schizoaffective disor-
der, manic, chronic.” He stated his “firm opinion that [Cox]
[wa]s not able to effectively cooperate with counsel in the
defense of his case and [wa]s not competent to stand trial,”
urging that Cox “should be hospitalized for treatment.”

   The trial judge held a competency hearing on June 25,
1991, and considered the reports of the doctors who had
examined Cox over the past year. On August 6, 1991, the trial
judge held Cox incompetent to stand trial, found that Cox
“would constitute a danger to the safety of himself and to
society if released from custody,” and concluded “that com-
mitment is required for a determination of his ability to attain
competence.” Cox was transferred to the Lakes Crossing Cen-
ter, a mental health facility.
  3
    Dr. O’Gorman evaluated Cox again a second time and found his emo-
tion “controlled,” “no evidence of hallucinations,” and repeated his find-
ing that Cox has a “paranoid personality” but no “psychotic reaction” and
was thus competent to assist his attorney at trial and understand the
charges and potential penalties.
12234                    COX v. DEL PAPA
   On January 2, 1992, the trial court impaneled a “Sanity
Commission” to reevaluate Cox. The Sanity Commission,
guided by the reports of three doctors, opined that Cox was
still incompetent. The trial court recommitted Cox to Lakes
Crossing on February 11, 1992, and ordered that Cox receive
periodic competency evaluations.

   On March 27, 1992, the trial judge impaneled a second
Sanity Commission, received its reports, and found that Cox
had become competent to stand trial. The court scheduled the
trial to begin, and Cox and the government stipulated that the
death penalty would not be pursued. The parties also stipu-
lated that the court would determine the sentence if Cox were
found guilty. However, the trial judge rejected the sentencing
stipulation, believing state law to require the jury to decide
the sentence.

                                  B

   Trial began on May 24, 1993, on the charge of first degree
murder.4 Cox was represented by counsel. At trial, Officers
Tyman and Ransom testified to the inculpatory statements
that Cox made to them at the time of his arrest. Detectives
Scroggin and Calvert testified to the inculpatory statements
that Cox made to them during the car ride from Arizona to
Nevada. A jury found Cox guilty of first degree murder and
rendered a special verdict imposing life in prison without the
possibility of parole.

   In due course, Cox appealed to the Nevada Supreme Court,
which held that state law did not require that a jury impose
sentence and that the trial court should have sentenced Cox,
pursuant to the parties’ stipulation. It remanded the case for
resentencing by the trial judge. On September 29, 1994, the
trial court resentenced Cox to life in prison without possibility
  4
   The court amended the criminal information to remove “with use of a
deadly weapon.”
                          COX v. DEL PAPA                        12235
of parole. Cox appealed his sentence on grounds of judicial
bias, but the Supreme Court of Nevada affirmed.

   Still seeking relief in state court, Cox filed a Motion for
Acquittal and a Motion for an Advisory Opinion. Construing
these motions as a habeas corpus petition, the state trial court
rejected Cox’s claims of ineffective assistance of counsel at
trial and at sentencing, and held that he waived his other
claims by failing to raise them on direct appeal. The Supreme
Court of Nevada affirmed this final state appeal on April 10,
1998.

                                   C

   Cox next petitioned for habeas relief under 28 U.S.C.
§ 2254, asserting various constitutional violations including
ineffective assistance of counsel at trial and sentencing.5

   The district court deemed several claims unexhausted and
offered Cox a choice between abandoning them or having the
court dismiss the petition in toto “so that [Cox] c[ould]
attempt to exhaust his unexhausted claims and thereafter
return with a petition ready for review on the merits of all his
claims.” Cox chose to abandon the unexhausted claims—
which, importantly, included his claim of ineffective assis-
tance of counsel at trial. Ultimately, the district court denied
the habeas petition and Cox’s request for a certificate of
appealability, but a panel of our court granted the certificate
and Cox timely appealed.
  5
   The Antiterrorism and Effective Death Penalty Act of 1996
(“AEDPA”) governs this case, because Cox filed his original federal
habeas petition on August 24, 1998. Under AEDPA, we review the district
court’s decision to deny a habeas petition de novo. Benn v. Lambert, 283
F.3d 1040, 1051 (9th Cir. 2002).
   A habeas petition must be denied unless the state court decision was
“contrary to, or involved an unreasonable application of, clearly estab-
lished Federal law, as determined by the Supreme Court of the United
States.” 28 U.S.C. § 2254(d)(1)
12236                  COX v. DEL PAPA
                               II

  Cox first argues that because the state trial court received
psychiatric evaluations that revealed some doubts as to his
competency to stand trial, the court should also have ordered,
sua sponte, a hearing on his cognitive ability to waive his
Miranda rights.

                               A

   [1] The Supreme Court has never held that a trial court
must order sua sponte a hearing regarding a defendant’s cog-
nitive ability to waive his Miranda rights. In Miranda v. Ari-
zona, 384 U.S. 436, 444 (1966) itself, the Court has
“concluded that in the context of ‘custodial interrogation’ cer-
tain procedural safeguards are necessary to protect a defen-
dant’s Fifth and Fourteenth Amendment privilege against
compulsory self-incrimination.” Rhode Island v. Innis, 446
U.S. 291, 297 (1980). Before a court may introduce state-
ments made by a suspect in custody and under interrogation,
“[t]he government has the burden of proving that the defen-
dant has knowingly and voluntarily waived his Miranda
rights.” United States v. Heldt, 745 F.2d 1275, 1277 (9th Cir.
1984) (internal citations omitted). Although “the State need
prove waiver only by a preponderance of the evidence,” Colo-
rado v. Connelly, 479 U.S. 157, 168 (1986), “[t]his burden is
great” and “[w]e must indulge every reasonable presumption
against waiver of fundamental constitutional rights.” Heldt,
745 F.2d at 1277. The government satisfies its burden only if
it makes two prerequisite showings:

    First, the relinquishment of the right must have been
    voluntary in the sense that it was the product of a
    free and deliberate choice rather than intimidation,
    coercion, or deception. Second, the waiver must
    have been made with a full awareness of both the
    nature of the right being abandoned and the conse-
    quences of the decision to abandon it. Only if the
                            COX v. DEL PAPA                          12237
      “totality of the circumstances surrounding the inter-
      rogation” reveal both an uncoerced choice and the
      requisite level of comprehension may a court prop-
      erly conclude that the Miranda rights have been
      waived.

Moran v. Burbine, 475 U.S. 412, 421 (1986) (emphasis
added).

    The distinction between a claim that a Miranda waiver was
not voluntary, and a claim that such waiver was not knowing
and intelligent, is important. “The voluntariness of a waiver
. . . has always depended on the absence of police overreach-
ing.” Colorado, 479 U.S. at 170. In other words, the voluntar-
iness component turns upon external factors, whereas the
cognitive component depends upon mental capacity.
Although courts often merge the two-pronged analysis, the
components should not be conflated.6 Here, Cox challenges
only the cognitive component.

                                     B

   Cox claims that lack of mental capacity bars admission of
his statements to Officers Tyman and Ransom upon his arrest,
as well as his statements to Detectives Scroggin and Calvert
on the ride from Arizona to Nevada. But, Miranda only
applies to the first set of statements; the latter statements were
clearly spontaneous.7 Although Cox correctly notes that the
government “do[es] not argue that [he] was not in custody,”
  6
     The distinction is reflected in the different standards of review: the
question of voluntariness (whether the defendant’s will was overborne) is
reviewed de novo, but the question of cognitive capacity (whether the
defendant had the requisite mental state as a factual matter) is reviewed
for clear error. Collazo v. Estelle, 940 F.2d 411, 415-16 (9th Cir. 1991) (en
banc).
   7
     Cox objects that “an inquiry was never made as to his competency to
waive his Miranda rights in March and May of 1990.” (emphasis added).
12238                       COX v. DEL PAPA
Miranda applies only “where a suspect in custody is subjected
to interrogation.” Innis, 446 U.S. at 300 (emphasis added).8

   Cox does not dispute that Detective Scroggin told him that
the detectives “were not going to question him about the inci-
dent at all.” Therefore, we confine our analysis to the state-
ments he made to Officers Tyman and Ransom when they
held him in custody and interrogated him in his Las Vegas jail
cell.

                                    C

  To show valid waiver, the government offered Officer
Tyman’s testimony, which indicated that Cox had “ac-
knowledge[d] that he understood the Miranda warnings”; Cox
did not present evidence to suggest otherwise.9 However, Cox
  8
     In Innis, officers investigating a murder arrested a suspect, but the
shotgun used to commit the crime had not been found. Innis, 446 U.S. at
294. During the car trip, two officers conversed, and one commented that
“ ‘there’s a lot of handicapped children running around in this area, and
God forbid one of them might find a weapon with shells and they might
hurt themselves.’ ” Id. at 294-95. The “officers’ comments struck a
responsive chord,” and the suspect was “suddenly [ ] moved to make a
self-incriminating response [offering to show the officers the location of
the gun].” Id. at 303. The Court held that the suspect’s right to counsel
was not violated, because “the respondent was not subjected by the police
to words or actions that the police should have known were reasonably
likely to elicit an incriminating response.” Id.
   9
     The record includes a mental health report written in 2000, in which
the examiner found that Cox suffered from a delusional or paranoid disor-
der and retrospectively opined that “without treatment, it [wa]s inconceiv-
able that Mr. Cox’s condition improved and he was mentally competent
[to stand trial].” The examiner also opined that Cox’s “statements to the
arresting officers may not have resulted from a knowing and intelligent
waiver of his Miranda rights.” Although the examiner concluded that
“Cox has a delusional disorder affecting his ability to make rational deci-
sions including waiving his Miranda rights,” he did not go so far as to
state that Cox’s waiver was, in fact, not knowing and intelligent. It is not
clear what additional medical examination would have helped illuminate
that issue, and Cox does not argue that further examination would refute
the government’s testimonial evidence supporting the validity of the
waiver.
                            COX v. DEL PAPA                          12239
claims that the trial court’s early finding of incompetency
should have alerted both his lawyer and the court, sua sponte,
to the need to conduct an evaluation and hearing as to whether
he had the mental capacity to waive his Miranda rights.10
Without holding a special hearing and evaluation of compe-
tency, Cox argues, the trial court could not find a valid
Miranda waiver.

   The Nevada Supreme Court rejected this argument, noting
that “Cox d[id] not claim his Miranda waiver was invalid; he
merely complain[ed] that there was never a formal evaluation
of its validity.” In any event, Cox argues that the state trial
court violated due process by ignoring all obvious signs that
he lacked the psychological capacity at the time of arrest to
understand and knowingly waive his Miranda rights.

   [2] Cox primarily relies on Johnson v. Zerbst, 304 U.S. 458
(1938), to support his view that a trial court has a protective
duty to hold a hearing sua sponte on whether a defendant in
these circumstances validly waived his Miranda rights. Zer-
bst, however, addressed a waiver of the Sixth Amendment
right to counsel. There, the trial court made no finding that the
defendants knowingly and intelligently waived their right to
counsel and permitted the trial to proceed, whereupon the
defendants were tried, convicted, and sentenced, without
assistance of counsel. Id. 460. The Supreme Court reversed.
“The Sixth Amendment withholds from federal courts, in all
criminal proceedings, the power and authority to deprive an
  10
     Cox’s counsel objected to the introduction of Detective Scroggin’s
report regarding Cox’s statements in the car, but Miranda does not apply
to such spontaneous statements, as explained above. Furthermore, the law-
yer simply objected to the tardy nature of the disclosure of certain written
statements by Detective Scroggin, which included details previous reports
had not. Such objection, of course, did not address Cox’s competence to
waive his Miranda rights.
   Most importantly, Cox’s counsel never objected to the introduction of
the statements Cox made to Officers Tyman and Ransom on March 22,
1990.
12240                   COX v. DEL PAPA
accused of his life or liberty unless he has or waives the assis-
tance of counsel.” Id. at 463. To protect the right to counsel,
a court must ascertain affirmatively that waiver is knowing
and intelligent:

    The constitutional right of an accused to be repre-
    sented by counsel invokes, of itself, the protection of
    a trial court, in which the accused—whose life or lib-
    erty is at stake—is without counsel. This protecting
    duty imposes the serious and weighty responsibility
    upon the trial judge of determining whether there is
    an intelligent and competent waiver by the accused.
    While an accused may waive the right to counsel,
    whether there is a proper waiver should be clearly
    determined by the trial court, and it would be fitting
    and appropriate for that determination to appear
    upon the record.

Id. at 465 (emphasis added).

   The Court then remanded the case, with the instruction that
the defendant bore the burden of proof to show that “he did
not competently and intelligently waive his right to counsel.”
Id. at 469. Indeed, the Court shifted the burden of proof of
waiver: “Where a defendant, without counsel, acquiesces in a
trial resulting in his conviction and later seeks release by the
extraordinary writ of habeas corpus, the burden of proof rests
upon him to establish that he did not competently and intelli-
gently waive his constitutional right to assistance of
[c]ounsel.” Id. at 468-69 (emphasis added); see also United
States v. Santiago Soto, 871 F.2d 200, 201 (1st Cir. 1989)
(stating that “the conventional wisdom among our sister cir-
cuits is that, absent a defendant’s request for a hearing on the
issue of voluntariness, or at least an objection to the admis-
sion of an incriminating statement or confession into evi-
dence, the requirement of a hearing is waived”).

  [3] Cox invokes Zerbst for the proposition that the “protect-
ing duty” articulated there applies equally to Miranda waiv-
                           COX v. DEL PAPA                          12241
ers. He leans on Minnick v. Mississippi for support: “[W]e
have adhered to the principle that nothing less than the Zerbst
standard for the waiver of constitutional rights applies to the
waiver of Miranda rights.” 498 U.S. at 160. However, the so-
called “Zerbst standard” to which the Court referred in Minn-
ick was merely the requirement that a waiver be voluntary,
knowing, and intelligent:

       The Zerbst waiver standard, and the means of apply-
       ing it, are familiar: Waiver is “an intentional relin-
       quishment or abandonment of a known right or
       privilege,” and whether such a relinquishment or
       abandonment has occurred depends “in each case,
       upon the particular facts and circumstances sur-
       rounding that case, including the background, expe-
       rience, and conduct of the accused.”

Id. at 159 (quoting Zerbst, 304 U.S. at 464). No Supreme
Court case suggests that the protective duty of the court
applies to Miranda waivers generally. Nor does AEDPA per-
mit an extension of the Supreme Court’s Zerbst decision to
the very different issue at bar. The need for court assistance
with respect to a waiver of trial counsel does not suggest a
similar need for court assistance when a defendant already has
the assistance of counsel.11 Thus, Zerbst cannot support Cox’s
claim that the trial judge had a protective duty to order a hear-
ing to ensure that his waiver was knowing and intelligent,
rather than determining simply whether the government had
met its burden of proof.

    [4] “Given the lack of holdings from [the Supreme] Court
. . . it cannot be said that the [Nevada Supreme C]ourt ‘unrea-
sonabl[y] appli[ed] clearly established Federal law.’ ” Carey
v. Musladin, 127 S. Ct. 649, 654 (2006) (citing § 2254(d)(1)).
  11
   The defendant may, of course, elect to represent himself. And if he
chooses representation by another, who then fails to assist him adequately,
he may file an ineffective assistance of counsel claim.
12242                     COX v. DEL PAPA
Therefore, Cox is not entitled to habeas relief on his sua
sponte hearing claim.

                                  III

  Cox also argues that he suffered from ineffective assistance
of counsel because defense counsel failed to develop and to
present a mitigating case at sentencing.12

                                  A

  [5] To prevail on an ineffective assistance of counsel claim,
a defendant must show that his counsel’s performance was
deficient and prejudiced the outcome. Strickland v. Washing-
ton, 466 U.S. 668, 693-94 (1984).

       “[To establish deficiency,] a defendant must show
       that counsel’s representation fell below an objective
       standard of reasonableness.” To establish prejudice
       he “must show that there is a reasonable probability
       that, but for counsel’s unprofessional errors, the
       result of the proceeding would have been different.
       A reasonable probability is a probability sufficient to
       undermine confidence in the outcome.”

Williams, 529 U.S. at 390-91 (quoting Strickland, 466 U.S. at
688, 694).

   [6] In Wiggins v. Smith, 539 U.S. 510 (2003), the Supreme
Court explained that the Strickland standard governs coun-
sel’s obligation to investigate and to present mitigating evi-
dence at sentencing. In Wiggins, two defense lawyers limited
their investigation to Wiggins’s Pre-Sentence Investigation
Report and Department of Social Services records. Id. at 533.
  12
    Cox formally abandoned his claim that trial counsel was ineffective
because “he made no effort to have Cox examined to determine if he was
competent to be [re]sentenced in September, 1994.”
                       COX v. DEL PAPA                    12243
They investigated no further, although they were aware of
Wiggins’s troubled background. The Court found that their
limited “investigation into Wiggins’ background did not
reflect reasonable professional judgment” and was “neither
consistent with the professional standards that prevailed . . .
nor reasonable in light of the evidence counsel uncovered in
the social services records.” Id. at 534. The lawyers’ deficient
performance prejudiced Wiggins, because available evidence
of his “severe privation and abuse” and the “physical torment,
sexual molestation, and repeated rape [he suffered during
many] years in foster care,” id. at 535, “ ‘might well have
influenced the jury’s appraisal’ of Wiggins’ moral culpabili-
ty.” Id. at 538.

   [7] The Court’s decision in Wiggins did not alter the stan-
dard set forth in Strickland. Nor did the case unsettle the rule
that counsel has “ “wide latitude . . . in making tactical deci-
sions” and “[j]udicial scrutiny of counsel’s performance must
be highly deferential.” Strickland, 466 U.S. at 689. However,
Wiggins did make clear that deference should not be given
unless counsel completes an adequate investigation. See Wig-
gins, 539 U.S. at 536 (“[C]ounsel were not in a position to
make a reasonable strategic choice . . . because the investiga-
tion supporting their choice was unreasonable.”). What con-
stitutes an adequate investigation again requires reference to
Strickland:

    [Counsel] has a duty to make reasonable investiga-
    tions or to make a reasonable decision that makes
    particular investigations unnecessary. In any ineffec-
    tiveness case, a particular decision not to investigate
    must be directly assessed for reasonableness in all
    the circumstances, applying a heavy measure of def-
    erence to counsel’s judgments.

    The reasonableness of counsel’s actions may be
    determined or substantially influenced by the defen-
    dant’s own statements or actions . . . . In short,
12244                       COX v. DEL PAPA
       inquiry into counsel’s conversations with the defen-
       dant may be critical to a proper assessment of coun-
       sel’s investigation decisions.

Strickland, 466 U.S. at 691.

                                    B

   We must therefore determine whether the Nevada Supreme
Court’s decision to deny Cox relief was “contrary to, or
involved an unreasonable application of, clearly established
Federal law, as determined by the Supreme Court of the
United States” with respect to his claim that his counsel did
not fulfill his duty to investigate and to present available miti-
gating evidence.13 28 U.S.C. § 2254(d)(1). A review of the
resentencing proceeding is essential.

   First, the judge noted that the sentencing choices were “life
with and life without the possibility of parole,” and asked Cox
whether he had anything to suggest: “This is your time to tell
me what you think is appropriate relative to the sentence.”
Cox responded by insisting on his innocence and noting that
his wife, who was present but whom he “ha[d no]t seen in
three years,” also believed he was innocent. Cox then cited
several mitigating circumstances, such as that he “had no
problems or complaints within the system,” was “not a trou-
blesome person,” and “ha[d] no prior records in regards to
being an adult offender.” He also noted “mitigating circum-
stances which were not brought up in the trial,” including “the
  13
     Strickland, Williams, Wiggins, and Schriro v. Landrigan, 127 S.Ct.
1933, 1942 (2007), described infra at 12250-51, all involved the assistance
of counsel in the penalty phases of capital cases. They did not expressly
state that the same standard would apply in non-capital cases, such as the
one at bar. However, the government implicitly agrees with applying this
standard to non-capital cases, for it also relies upon Supreme Court capital
sentencing precedents to illuminate the proper standard.
  In any case, Cox’s claims lack merit even when evaluated under the
high standard set forth in the Court’s death penalty jurisprudence.
                           COX v. DEL PAPA                          12245
cocaine incident and the conspiracy to set me up to cause my
death and robbery, which you know I had a large amount of
money”14 and Wilson’s “extensive criminal record.”15 He
added that although he “grieve[d] for the loss of a life,” he felt
that Wilson had been “causing many losses . . . and heartaches
of families, too” and “[i]t’s just that at this time, [the] situa-
tion went the other way.”

   The court then allowed Cox’s counsel to offer mitigating
evidence. The lawyer began by giving the judge a brief letter
that Cox’s wife had “just handed [him].” Then counsel
reminded the judge that the prosecution had offered Cox a
plea agreement whereby Cox would have pled guilty to sec-
ond degree murder and would have faced only a sentence of
five years to life in prison.

   Next, counsel argued that the court should consider Cox’s
potential for safe release. He argued that Cox was no longer
inclined toward the kind of violent behavior that he had
exhibited as a juvenile.16 Reading from the most recent Pre-
Sentence Investigation report, the lawyer noted that “[s]ince
his arrival in [prison], [Cox] ha[d] sustained no disciplinary
sanctions and ha[d] adjusted within acceptable standards” and
“[c]ontact with his current case worker indicated Cox pro-
grams well.” Counsel pointed out that another report stated
that Cox was “polite and courteous at all times,” was “not a
problem to anyone,” and was “trying to cope within the sys-
tem.”
   14
      Cox apparently was convinced that Wilson conspired to take his
money (and acted as if demonically possessed). See supra at 12231
(describing testimony by Cox’s arresting officers that he had told them “he
was framed, that it was self-defense,” and “the girl had come to him with
fangs and fingernails”).
   15
      The judge excluded such evidence and Cox sought federal habeas
relief on that ground, which the district court denied. Cox does not appeal
that ruling.
   16
      See infra note 19 & accompanying text.
12246                  COX v. DEL PAPA
   Counsel then explained that his own investigations had
revealed some positive aspects of Cox’s character and poten-
tial for living a lawful existence. During the long period
between trial and sentencing, the lawyer explained, he had
traveled to Northern California and had spoken to Cox’s wife
and “some of his associates and others.”

    I met with a man in San Francisco who worked for
    the City of San Francisco in their housing depart-
    ment who talked to me and told me of the marvelous
    work Steve did as journeyman carpenter on this gen-
    tleman’s personal properties. He said he would trust
    him with his life. Because, he said he did beautiful
    work, he was honest and truthful in everything that
    he did for him.

  Counsel stated that others had expressed “that same feeling
about [Cox] and didn’t understand why he was in the [crimi-
nal] situation.” They speculated that his actions were caused
by “the drugs that he got involved with.”

   Building upon that suggestion, counsel sought to reduce
Cox’s culpability by emphasizing his “use of cocaine” and
“mental problems.” He explained that Cox had misunderstood
the fits Wilson was having and had honestly believed she
would hurt him: “He responded to something he thought was
taking place because of the drugs that were in his system and
what was going on in that hotel room. And he’s convinced to
this day that’s what happened; you’ve heard him say that.”
(referencing Cox’s testimony that he believed Wilson would
harm him).

   At this point, however, Cox interrupted his counsel: “Your
Honor, there was no drugs in my system. And I refute that
allegation by my counsel, if I may, as a defendant.” He
insisted that Wilson was involved in a conspiracy to rob him
and began to repeat his testimony on this score, although the
judge reassured him that he had “heard all that at trial.” Still
                        COX v. DEL PAPA                    12247
attempting to persuade the judge that he was not delusional,
Cox told the judge: “I refused to take drugs, even at Lakes
Crossing [mental health facility]. No drug was ever dispensed
to me.”

    Confronted with this resistance from Cox, counsel changed
his strategy. He emphasized that sentencing Cox to life in
prison with possibility of parole would not endanger society,
because it would simply leave open the possibility that, at
some later point, Cox might be deemed no longer to pose a
threat to society: “I think it should be within the power of the
Parole Board to look at him and say is he of such a state of
mind that it’s safe for him to be on the streets again. They
should have that power. And when that time comes, I think
it is appropriate that they be allowed to seriously consider that
and give him that opportunity.” Counsel concluded by urging
the court to impose the lesser sentence of “life with the possi-
bility of parole.”

   The court declined to do so, however, and imposed life
without possibility of parole. Although the judge agreed with
Cox’s counsel that Cox was not “a typical murderer,” he
noted that the crime was not “a typical murder.” He further
explained that “the nature of the killing itself, [Cox’s] contin-
uing indication to me that the problems have probably
stemmed, in large part, from the use of crack cocaine continue
to give real problems to [him] in understanding fully, or per-
ceiving fully the real world as others perceive it.” As a result,
the judge concluded that Cox remained “a dangerous person.”
He told Cox that if he was “again going to see the light of
day, . . . it should be more a matter for the Pardons Board
rather than the Parole Board.”

                               C

   Cox now seeks to overturn his sentence, claiming ineffec-
tive assistance of counsel. He argues that “[c]ounsel[ ] fail[ed]
to put forth any effort to educate the court about Cox’s true
12248                  COX v. DEL PAPA
psychiatric and behavioral condition and Cox’s realistic
expectations of improvement with appropriate treatment.” In
particular, he argues that counsel should have investigated
and presented evidence of Cox’s “serious mental problems,”
“severe cocaine addiction,” and “how drug use interacted with
Cox’s mental illness,” as well as evidence of “positive behav-
ioral consequences if Cox received appropriate mental health
care and drug rehabilitation opportunities.” He objects that
counsel offered no live witnesses, although expert witnesses
“were readily available” and his counsel could have called
“business associates who spoke well about Cox’s character
and work ethics [sic].”

                              1

   [8] Cox’s arguments are without merit, particularly viewed
in light of AEDPA’s deferential standard of review. First, he
fails to show a failure to investigate. His counsel drew to the
court’s attention Cox’s “mental problems,” which were
already documented by at least four psychiatrists. The
detailed reports and the court’s own investigation into Cox’s
competency to stand trial, see supra at 12232-34, did not sug-
gest that additional research would have been fruitful. Nor did
Cox present any specific background facts that counsel should
have pursued. Counsel had no duty to present mitigating evi-
dence that did not exist. Even on appeal, Cox does not say
what evidence counsel could have found. Without any specifi-
cation of the mitigating evidence that counsel failed to
unearth, Cox’s claim must fail. See James v. Borg, 24 F.3d
20, 26 (9th Cir. 1994) (“Conclusory allegations which are not
supported by a statement of specific facts do not warrant
habeas relief.”).

   [9] In any event, our own search of the record shows that
there was no “powerful” mitigating evidence left unearthed.
Wiggins, 539 U.S. at 534. Cox “noted no significant problems
during his childhood and/or adolescence.” The troubles he
had encountered in his adult relationships hardly suggested
                            COX v. DEL PAPA                          12249
mitigating circumstances: he had fathered two illegitimate
children and married the mother of a third (but separated from
her prior to the crime); none of the children or their mothers
lived with him.17 As for his drug use, Cox “denie[d] a prob-
lematic association with alcohol or illegal controlled sub-
stances” although he did “acknowledge weekly consumption
of marijuana from age 20 until age 31 and recreational usage
of cocaine from the early 1980’s until December 1989.”18
These facts did not suggest that further investigation of Cox’s
life history would unearth mitigating evidence.

                                     2

   [10] Nor was counsel deficient for failing to emphasize
Cox’s limited criminal record. The Pre-Sentence Report
(“PSR”) already revealed that Cox “possesse[d] limited prior
contacts within the criminal justice system” but that “all of his
prior contacts have been for violent crimes.” (emphasis
added).19 Defense counsel reasonably and presumably strate-
gically chose to emphasize Cox’s good behavior while incar-
cerated after the crime rather than draw further attention to
Cox’s prior record of limited but violent incidents.
   17
      Ten years after the crime, his youngest son still did not know he was
in prison and his wife had not visited him for the previous six years.
   18
      A report commissioned by the Assistant Federal Public Defender in
2000 did not reveal further evidence. The report simply confirmed what
psychiatrists had told the trial court: that Cox was “cooperative and can-
did” but had “illogical thought progressions that involved his cocaine use
and the belief in a conspiracy against him” and “a delusional disorder,
which is also known as a paranoid disorder.” The report offered no new
evidence of drug effects that counsel could have unearthed in 1990. See
supra note 10 (describing the report).
   19
      The PSR stated that Cox “voluntarily acknowledge[d] entering the
juvenile justice system at approximately age 16 and sustaining three refer-
rals for violent type offenses . . . . He entered the adult criminal justice
system at approximately age 30, sustaining one misdemeanor conviction
for a violent offense.”
12250                      COX v. DEL PAPA
   More troubling, but still not deficient, especially in light of
Supreme Court precedent, was counsel’s decision not to
investigate or present additional evidence regarding Cox’s use
of drugs. The trial court had already ordered psychiatric
reports from four doctors and impaneled two Sanity Commis-
sions to ascertain Cox’s mental state. These reports had
revealed Cox’s mental problems, but had also noted that he
denied a drug problem and insisted that he only used cocaine
in order to study its pernicious effects on others. In any case,
counsel did argue that Cox’s drug use affected his judgment,
and the existing records did not alert him to a further need to
investigate or present evidence on that score.20

  [11] Furthermore, even if counsel could have discovered
additional evidence regarding the influence of drugs upon
Cox, no prejudice resulted. First, the judge considered Cox’s
drug use to be aggravating evidence, because he felt that the
“use of crack cocaine continue[d] to give real problems to
[Cox] in understanding fully, or perceiving fully the real
world as others perceive it,” and made him “a dangerous per-
son.” Offering further evidence of Cox’s drug problem could
have exacerbated the judge’s view that he was dangerous.

   [12] Second, Cox had continuously—and strenuously—
protested when counsel suggested that his behavior was the
result of drug use. Had his lawyer attempted to continue that
line of argument, the record suggests that Cox would have
stopped him. The Supreme Court recently held that no preju-
dice could be found in a case where the defendant had inter-
rupted counsel in a similar manner. In Schriro v. Landrigan,
127 S.Ct. 1933, 1942 (2007), counsel had attempted to put a
  20
    Cox admitted as much: In an amended state habeas petition, Cox
alleged that “Counsel failed to attack the first degree murder charge by
presenting evidence of Cox’s cocaine use, even though the defense of vol-
untary intoxication was available to defeat the necessary intent element,
and even though counsel later argued these facts in hopes of mitigating
the sentence imposed.”
                        COX v. DEL PAPA                    12251
positive spin on the defendant’s actions, but every time he
attempted to do so, the defendant interrupted and opposed the
introduction of mitigating evidence. The Court held that coun-
sel was not ineffective, even though he failed to present any
mitigating evidence, because “regardless of what information
counsel might have uncovered in his investigation, [the defen-
dant] would have interrupted and refused to allow his counsel
to present any such evidence.” Id. The Court explained that
prior precedent did not suggest otherwise:

    Neither Wiggins nor Strickland addresses a situation
    in which a client interferes with counsel’s efforts to
    present mitigating evidence to a sentencing court.
    . . . [I]t was not objectively unreasonable for [the
    state] court to conclude that a defendant who refused
    to allow the presentation of any mitigating evidence
    could not establish Strickland prejudice based on his
    counsel’s failure to investigate further possible miti-
    gating evidence.

Id. Under the Court’s reasoning in Landrigan, as well as con-
sideration of the judge’s stated belief that Cox’s drug use
underscored his dangerousness, counsel’s decision not to
present further evidence of his drug use was not prejudicial.

                               3

   Finally, Cox’s argument that counsel should have sought
out and presented witnesses at resentencing does not merit
relief. Cox argues that his wife could have testified. But hav-
ing her testify would have been a risky strategy, given that
Cox and his wife were separated, she was raising his son
without him, and by the time of resentencing, they had not
seen one another for three years. Although we do not know
the contents of her letter, we know that it was brief. It was not
unreasonable to avoid the risk of having her cross-examined.

  Cox also urges that counsel should have called his “busi-
ness associates” to testify, rather than simply paraphrasing
12252                   COX v. DEL PAPA
their assertions that Cox was honest. But their live testimony
would have done little to mitigate his culpability for the mur-
der, which they expressly stated they could not understand
(suggesting that they did not appreciate the dangerous aspects
of his character). Furthermore, a decision to paraphrase the
most positive statements made by Cox’s associates falls
within counsel’s “wide latitude . . . in making tactical deci-
sions.” Strickland, 466 U.S. at 689.

   Nor was it unreasonable for counsel to comment upon the
expert statements in the record rather than call the experts to
testify directly to the court. Cox offers no reason to believe
that the court would have learned anything different or in
addition to their reports, and he does not mention any expert
who might have offered a new and more powerful mitigating
argument. Even during habeas proceedings, Cox did not cite
evidence that “should have been discovered” (beyond his gen-
eral assertions that counsel should have investigated his men-
tal problems and drug use further).

   The record suggests no grounds for counsel to believe other
witnesses were available who could have testified to Cox’s
reduced culpability or potential for rehabilitation. Indeed, dur-
ing the trial Cox sought to speed up the proceedings, explain-
ing that he was tired of the delay in his case and that no
further investigation was needed because “the witnesses have
all been accounted for that pertain to my case.” (emphasis
added). The Supreme Court has made clear that “when the
facts that support a certain potential line of defense are gener-
ally known to counsel because of what the defendant has said,
the need for further investigation may be considerably dimin-
ished or eliminated altogether.” Strickland, 466 U.S. at 691.

                               4

   [13] In sum, after scouring the record for mitigating evi-
dence that counsel failed to present—and in light of Cox’s
failure to present any such evidence on his own—we must
                        COX v. DEL PAPA                    12253
conclude that counsel’s investigation was appropriate and rea-
sonable in light of the facts and issues in this case and the
applicable AEDPA deferential standard of review. Therefore,
the Nevada Supreme Court’s denial of relief, despite Cox’s
claim of ineffective assistance of counsel at resentencing, can-
not be said to be “contrary to, or . . . an unreasonable applica-
tion of, clearly established Federal law, as determined by the
Supreme Court.” § 2254.

                               IV

  For the foregoing reasons, the decision of the district court
denying federal habeas relief is

  AFFIRMED.
