Pinholster v. Ayers

Opinion by Judge MILAN D. SMITH, JR.; Dissent by Chief Judge KOZINSKI.

MILAN D. SMITH, JR., Circuit Judge:

Scott Lynn Pinholster (Pinholster) was sentenced to death after a jury convicted him of double murder with a knife in the course of a home robbery and burglary. After exhausting his state remedies, Pin-holster sought a writ of habeas corpus in federal district court in which he alleged, among other claims, ineffective assistance of counsel at both the guilt and penalty phases of his trial. Applying the standards of the Antiterrorism and Effective *655Death Penalty Act of 1996 (AEDPA), Pub.L. No. 104-132, 110 Stat. 1214, in its final ruling, the district court upheld Pin-holster’s conviction, but granted habeas relief on his death sentence because the court found that trial counsel’s deficient performance at the penalty phase of the trial unconstitutionally prejudiced Pinholster’s defense.

A three-judge panel of this court affirmed the district court’s guilt phase determination but reversed its grant of habeas relief on the penalty phase. Pinholster v. Ayers (Pinholster II), 525 F.3d 742 (9th Cir.2008). Sitting en banc, we affirm the district court. Although the denial of Pin-holster’s guilt phase ineffective assistance claim was appropriate, his penalty phase ineffective assistance claim warrants habeas relief even when considered under AEDPA’s deferential standards.

I. FACTUAL AND PROCEDURAL BACKGROUND1

A. The Prosecution’s Guilt Phase Case

As recounted in the California Supreme Court’s opinion on direct appeal, Art Corona (Corona), an accomplice in the commission of most of the crimes charged, served as the prosecution’s primary witness. Pinholster v. Ayers (Pinholster I), 1 Cal.4th 865, 4 Cal.Rptr.2d 765, 824 P.2d 571, 582 (1992). At trial, Corona testified that he, Pinholster, and Pinholster’s co-defendant, David Brown (Brown), were attending a party at Pinholster’s apartment on the evening of January 8, 1982, when Pinholster solicited them to rob Michael Kumar, a local drug dealer. Id. Pinholster told the others that he anticipated forcing entry into Kumar’s home and taking drugs and money. Id.

As Corona drove towards Kumar’s house, Pinholster directed Corona to stop at Lisa Tapar’s residence. Id. Pinholster wanted Tapar to help with the robbery, but when he knocked on her door, she refused him entry and shut the door in his face. Id. In response, Pinholster took a buck knife from his belt, stabbed it through the door, and scratched a swastika and thunderbolts into the hood of her car. Id. Tapar, her father, and a third witness corroborated Corona’s description of this incident. Id.

When Pinholster, Brown, and Corona arrived at Kumar’s residence and found no one home, they broke in and ransacked it, taking a small amount of marijuana from a bedroom and spilling a green substance in the kitchen. Id. at 582-83. While they were searching the house, they heard a car pull up and saw Thomas Johnson and Robert Beckett (Kumar’s housesitters) approach, one of whom opened the front door and shouted that he would call the police. Id. at 583. Pinholster, Brown, and Corona all moved towards the rear door to leave, but Johnson and Beckett came to the back and blocked their way. Id. When Johnson tried to enter the house, Pinholster struck him in the chest three or four times, demanding drugs and money. Id. Johnson dropped his wallet on the ground and obeyed Pinholster’s order to sit down. Id. Pinholster then attacked Beckett as he approached, stabbing him in the chest. Id. Beckett dropped to the ground, and Pin-holster kicked him in the head repeatedly, took the wallet from Beckett’s pocket, and also picked up Johnson’s wallet. Id. *656Brown then stabbed Johnson in the chest, “bury[ing] his knife to the hilt.” Id. Johnson and Beckett died of their wounds.

Pinholster, Brown, and Corona then left Kumar’s house and drove back to Pinholster’s apartment. Id. On the way, Brown and Pinholster commented that they had “gotten them good.” Id. Pinholster washed his knife upon his return, and the three split the proceeds of the robbery: $23 and a quarter-ounce of marijuana. Id.

Although Pinholster called Corona the day after the crime and told him to “lie low,” Corona turned himself in two weeks later and gave a statement to police. Id. According to Corona, Pinholster threatened to blow him up on his way to court if Corona refused to invoke his right against self-incrimination, and testified against him. Id. Nevertheless, Corona testified against Pinholster and Brown and, at the end of the trial, pleaded guilty to burglary. Id.

Corona’s wife, Casey Corona, who was at Pinholster’s apartment when Pinholster, Brown, and her husband returned from Kumar’s residence, corroborated her husband’s testimony about the initiation, execution, and aftermath of the crime. Id. She testified that she watched Pinholster wash blood from his knife, and that she heard him say, “It had to be done the way it was done. We had to do what we had to do.” Id.

The prosecution also presented forensic evidence that Pinholster had been in Kumar’s home after the ransacking. Id. According to Corona’s testimony, Pinholster wore boots and jeans on the evening of the murders. Id. During their search of Pin-holster’s apartment, police discovered boots, a towel, and a pair of jeans, all with microscopic blood traces on them. Id. While the boots and the towel tested positive for human blood, the jeans were not tested to determine whether the blood on them was also human. Id. at 583-84. Additionally, when police arrested Brown, he was carrying a buck knife with human blood traces close to the hilt and with dimensions that matched a stab wound in Johnson’s body. Id. at 584. Police also discovered human blood on the inside forearm of Corona’s shirt sleeve, but did not find any blood on his knife. Id.

B. Pinholster’s Guilt Phase Case

During the guilt phase of his trial, Pin-holster testified on his own behalf and presented an alibi defense. Id. at 584-85. He boasted that he had committed hundreds of robberies over the previous six years, using a gun, but never a knife, to victimize drug dealers. Id. at 584. Although he admitted a prior kidnapping conviction with the use of a knife, he claimed that he pleaded to the aggravating circumstance only as part of a plea bargain. Id. Pinholster also admitted going to Kumar’s house and taking marijuana from the bedroom, but denied ransacking the residence or killing anyone. Id. Pin-holster asserted that Corona had asked him for Kumar’s address that night, and that Corona had gone to Kumar’s house later to steal some additional drugs and money. Id. at 585.

C. The Jury’s Guilt Phase Verdict

At the close of the guilt phase, the jury convicted Pinholster of first-degree murder and found that the following two multiple-murder special-circumstance allegations were true, making him eligible for a death sentence: first, he committed each murder during the course of a robbery and a burglary; and second, he personally used a knife. Id. at 581. The jury also convicted him of burglary, robbery, and intentional infliction of great bodily injury through personal use of a knife. Id.

*657D. The Prosecution’s Penalty Phase Case

At the penalty phase of the trial, Pinholster stipulated that he had a prior kidnapping conviction with the use of a knife, and that he was identified as having held the knife to the victim’s throat. Id. at 586. Pinholster also stipulated to numerous disciplinary infractions during his prison term for the kidnapping, such as throwing urine at guards, threatening to stab guards, and threatening to throw guards from an upper tier of the prison. Id. The prosecution presented testimony that Pinholster had a violent history with law enforcement, including: an outburst in court as a juvenile during which he threatened everyone in the room and struck a bailiff; resisting arrest as an adult by kicking one police officer in the back of the head while allegedly faking an epileptic seizure; making threats and kicking the X-ray machine when taken to the hospital after his arrest; starting a racial fight while in custody and kneeing an officer in the groin; and various other incidents of violence or threats of future violence while in custody, including death threats. Id. In addition, the prosecution presented testimony that Pin-holster was a well-known member of the juvenile gang community. Theodore Mesquita testified that Pinholster had once cut Mesquita’s arm with a razor, afterwards pursuing him on foot to the hospital where Mesquita required fifty stitches to close his wound. Id. at 586-87. Cathy Ann Smith, Pinholster’s ex-wife, also testified that Pinholster once broke her jaw while seeming to have an epileptic seizure. Id. at 587.

E. Pinholster’s Penalty Phase Case

Pinholster had been represented by, and later rejected, several different court-appointed attorneys to represent him in this case before he petitioned the court to permit him to represent himself, which he did from March 17 to July 13, 1983. Pinholster II, 525 F.3d at 751 n. 5. Pinholster later reconsidered, however, and the Los Angeles County Superior Court appointed Harry W. Brainard and Wilbur G. Dettmar to represent him during the guilt and penalty phases of his trial. Id.

On March 22, 1983, the State mailed a letter to Pinholster at the Los Angeles County Jail, informing him that the prosecution planned to offer aggravating evidence at the penalty phase. Id. at 751. When the guilt phase ended on April 24, 1984, Pinholster’s counsel moved to exclude the aggravating evidence on the ground that the prosecution had failed to provide reasonable notification under California Penal Code § 190.3. Id. The state trial court denied the motion, concluding that Pinholster had received actual notice of the State’s intention to seek the death penalty during the time period in which he represented himself. Id. at 751, 751 n. 6. In doing so, however, the court advised defense counsel that it would grant a defense motion to continue the penalty phase of the trial to allow Pinholster’s counsel to prepare a mitigation case. Id. at 751. Pinholster’s counsel declined the offer, stating that they did not believe that more time “would make a great deal of difference.”

Pinholster’s counsel had earlier consulted with Dr. John M. Stalberg, a psychiatrist, who examined Pinholster on March 11, 1984, about a week after the guilt phase of the trial began. Dr. Stalberg had received a copy of Pinholster’s police reports as well as a copy of his 1978 probation report, and examined Pinholster himself for one to two hours. He concluded that Pinholster “did not manifest any significant signs or symptoms of mental disorder or defect other than his antisocial personality disorder by history.” Based *658on his examination, Dr. Stalberg opined that Pinholster was cognitively functional, without brain damage, and noted that while Pinholster allegedly had epilepsy, he had not had a seizure for the past year and was not on medication. Pinholster’s trial counsel did not contact Dr. Stalberg again, nor did they consult with any other mental health expert.

Pinholster’s counsel billed a total of only 6.5 hours in preparation for the penalty phase of the trial.2 Brainard stated that while “Mr. Dettmar was primarily responsible for psychiatric, psychological, and other mental health issues in the case,” he had “no recollection of Mr. Dettmar having secured or reviewed any of [Pinholster’s] medical records, nor did [Brainard] see any [of them].” “So far as[Brainard] recollected], neither Mr. Dettmer nor [Brainard] interviewed any of Scott’s previous medical providers” even though they were “aware prior to trial that Dr. Dubin and other health care providers had treated Mr. Pinholster for seizure disorder.” In the same vein, Brainard admitted:

I do not recall interviewing or attempting to interview [Pinholster’s] family members or any other persons regarding penalty phase testimony, except Mrs. Brashears [sic], defendant’s mother. I have no recollection of seeing or attempting to secure [Pinholster’s] school records, juvenile records, medical records, or records of prior placements. I have no recollection of interviewing or attempting to interview [Pinholster’s] former teachers, counselors, or juvenile officers.

The limited preparation that was done included interviewing Pinholster’s mother, Burnice Brashear (Brashear), who later became the sole defense witness called at the proceeding. Brashear testified that Pinholster had been in several accidents as a small child. When Pinholster was two years old, Brashear accidentally ran over him with her car, badly injuring his head. When Pinholster was four or five, Brash-ear was involved in a car accident in which Pinholster’s head went through the windshield. Brashear also testified that Pin-holster did not get along well with his step-father, who was a strict disciplinarian to the point of abuse at times. She stated that Pinholster was disruptive in the classroom as a child, but “did much better” when sent to an academically handicapped class in third or fourth grade.

Brashear further testified that when Pinholster was about ten, she took him to a psychiatrist who recommended that he be placed in a mental institution. She rejected that recommendation because she “didn’t think he was that far gone.” Meanwhile, Pinholster began stealing things and playing “Robin Hood” around the neighborhood, which indicated to her that “something was not working right.” Pinholster eventually was sent to juvenile hall as a result of these thefts. As an adult, Pinholster had physical problems that included epilepsy, which Brashear understood to be the result of his being *659“beaten up pretty severely in jail” when he was eighteen. She also stated that he was on medication for that epilepsy, but that she did not know if he received the recommended medication while in prison.

Brashear then testified that her other children were “basically very good children,” although they had also been in trouble with the law. She specifically mentioned DUI charges for both her younger son and her “wild girl” daughter. Brash-ear emphasized, however, that her other children were not like Pinholster, who was a “show-off’ and had been in and out of mental institutions from the time he was twelve. She stated that the doctors had found “something wrong here outside of just bad behavior.” Brashear also testified that Pinholster “never really wanted for anything at home too much,” having had “everything normally materialwise that most people have,” and that although the family “didn’t have lots of money,” he always had “a roof over his head” and “decent clothes.” Finally, she indicated that although Pinholster was “a perfect gentleman” at home, his long stay in state prison had affected him so that it was difficult for him to remember that he could open doors and walk outside.

F. The Jury’s Penalty Phase Verdict and the State Trial Court’s Sentencing of Pinholster

Following Brashear’s testimony and two and a half days of deliberation, the jury returned a death verdict on each of the two murder counts on May 7, 1984, Pinholster II, 525 F.3d at 751-52, and the state trial court sentenced Pinholster accordingly.

G. The State Habeas Petition

After the California Supreme Court set aside one multiple-murder special circumstance but otherwise affirmed the judgment on direct appeal, Pinholster filed a state habeas petition in which he alleged, among other claims, ineffective assistance of counsel at both the guilt and penalty phases of his trial.

In support of his guilt phase ineffective assistance claim, he presented evidence that his counsel had failed to test the forensic evidence independently and to move to exclude prior bad acts evidence introduced by the prosecution. Pinholster also presented evidence that his counsel were ineffective during the penalty phase by failing to conduct an adequate investigation into his mental health. Specifically, he claimed that Dr. Stalberg, the expert consulted by his attorneys, had “unreasonably, incompetently and perfunctorily arrived at unsupported conclusions based upon inadequate investigation and analysis.” He also presented the testimony of Dr. George Woods, who also condemned Dr. Stalberg’s report and offered an alternative analysis. Dr. Woods indicated that Pinholster suffered from bipolar disorder, and that at the time of the murders, Pin-holster was in the throes of an epilepsy-related seizure. Dr. Woods also opined that Pinholster was incompetent to stand trial.

The California Supreme Court issued an order to show cause on the penalty phase ineffective assistance claim, but then vacated the order as improvidently granted and denied the petition “on the substantive ground that it is without merit.”

H. The Federal Habeas Petition

Pinholster filed a federal habeas petition on April 22, 1997. In this petition, Pinholster abandoned use of Dr. Woods’s testimony and instead presented the testimony of Dr. Stalberg, who stated that if trial counsel had provided him with Pinholster’s family history, particularly as related to medical disorders, he would have made *660further inquiry “before concluding that [Pinholster] had merely a personality disorder.” After the parties stipulated that the petition included new material facts and unexhausted claims, the district court dismissed the unexhausted claims and held the fully exhausted petition in abeyance.

The California Supreme Court denied Pinholster’s second state habeas petition “on the substantive ground that it is without merit.”3

The case then returned to federal district court, where Pinholster requested an evidentiary hearing. Pinholster II, 525 F.3d at 754. Applying pre-AEDPA law, the court denied an evidentiary hearing and granted summary judgment to the State on Pinholster’s guilt phase ineffective assistance claims, id. at 748, 754 n. 9, 756, but granted an evidentiary hearing on Pinholster’s penalty phase ineffective assistance claim, id. at 754. Pinholster prepared a declaration by Dr. Stalberg to serve as direct testimony for that hearing. During Dr. Stalberg’s subsequent deposition, however, he testified that nothing in the information compiled by the defense team altered his basic opinion that Pinholster “suffers from Antisocial Personality Disorder.” Defense counsel then dropped Dr. Stalberg from the case and substituted two new experts, Dr. Donald Olson and Dr. Sophia Vinogradov. Pinholster II, 525 F.3d at 755.

At the evidentiary hearing, as discussed in further detail in section III.B.3.b. of this opinion, Pinholster presented mitigation evidence that his counsel had failed to present at the penalty phase of his trial. This evidence included testimony that his childhood upbringing was much worse than his mother had described. His biological father was an unemployed drunk who was unfaithful to his mother, and the couple divorced shortly after Pinholster’s birth. His father had mood swings and fits of anger, and was eventually diagnosed as paranoid with narcissistic personality disorder. After his parents’ divorce, Pin-holster’s mother generally did not have enough money to provide for the children and, when she had money, usually spent it on herself. Pinholster’s grandmother, who often watched the children while his mother worked, used to “beat the hell out of’ him because he resembled his father.

Pinholster’s step-father came into his life when Pinholster was five years old, and was, according to Pinholster’s evidence, more than simply a strict disciplinarian. The step-father beat the children with his fists, a belt, and — on at least one occasion — a two-by-four board. Otherwise, he was “completely indifferent” to them. The additional evidence also showed that the family did not get enough to eat and lived in crime-ridden neighborhoods, and that the children ran wild, fre*661quently trashed apartments, and lacked any moral or other discipline.

Regarding his schooling, Pinholster presented testimony that he was a nice and intelligent child, but restless and hyperactive, unable to sit still and in need of a great deal of attention. Although his fourth-grade teacher arranged several appointments with his mother to discuss the situation, his mother generally failed to attend or, if she did attend, remained non-responsive throughout the appointment. After Pinholster had been arrested three different times when he was ten or eleven years old, the juvenile court placed him in a home for emotionally disturbed boys, after which he stayed at a state mental hospital for about five months. Although the psychiatric discharge report recommended his placement in a good foster home, that suggestion went unheeded. In seventh grade, Pinholster began using drugs, including marijuana, barbiturates, alcohol, acid, and cocaine. He became addicted to heroin while in the eighth grade. Thereafter, he was sent to juvenile hall at least nine times and to at least three schools for troubled boys, and was finally sent to prison at age nineteen following a conviction for kidnapping.

Pinholster also provided further details of his family’s criminal and mental history. His older brother, Alvin, was charged with the rape and sodomy of a fourteen-year-old, and was later diagnosed with schizophrenia and found to be incompetent to stand trial. Shortly after Pinholster’s parole from his kidnapping sentence, Alvin committed suicide. Pinholster’s younger brother, Terry, was diagnosed with mild depression and abused drugs, and his half-sister, Tammy, began drinking alcohol when she was eleven. When Tammy was seventeen, she was arrested with her boyfriend for sexually assaulting a fourteen-year-old girl. Guy, a half-brother, was diagnosed with manic depression, and Gary, another half-brother, was an alcoholic with severe mood swings.

Pinholster’s experts also testified that he had suffered brain damage that explained his aggressive, impulsive, and antisocial behavior. Dr. Olson, a pediatric neurologist, concluded that Pinholster sustained frontal-lobe injuries from the two childhood car accidents, as evidenced by the facts that Pinholster suffered from epilepsy and that he had an abnormal electroencephalogram (EEG) when he was nine years old. Dr. Vinogradov, a psychiatrist, diagnosed Pinholster with organic personality disorder brought on by childhood and later-life head trauma, and ruled out a diagnosis of antisocial personality disorder.

In light of this evidence, and applying pre-AEDPA law, the district court granted Pinholster’s habeas petition based on the “inadequacy of defense counsel in investigating and presenting mitigation evidence at the penalty phase” of his trial. The same day the district court filed its decision, however, the Supreme Court issued its opinion in Woodford v. Garceau, which held that AEDPA applies in capital habeas cases so long as the petition was filed after April 24, 1996. 538 U.S. 202, 207, 123 S.Ct. 1398, 155 L.Ed.2d 363 (2003). In response, the district court issued an addendum to its order, concluding that Pin-holster timely filed his federal habeas petition; that Pinholster was entitled to an evidentiary hearing under AEDPA; and that AEDPA did not affect the grant of habeas relief because “[t]he California Supreme Court did not adjudicate Pinholster’s claim that counsel was ineffective for failing to investigate and present mitigating evidence at the penalty phase.” The parties cross-appealed, and a three-judge panel of our court affirmed the district court’s guilt phase ineffective assistance determination, but reversed its grant of *662habeas relief on the penalty phase ineffective assistance claim. Pinholster II, 525 F.3d at 773. Upon the affirmative vote of a majority of the eligible judges in our court, we took the case en banc.

II. JURISDICTION AND STANDARD OF REVIEW

We have jurisdiction pursuant to 28 U.S.C. § 2253. We review a district court’s decision to grant or deny a writ of habeas corpus de novo, Lewis v. Mayle, 391 F.3d 989, 995 (9th Cir.2004), and the district court’s findings of fact for clear error, Bonin v. Calderon, 59 F.3d 815, 823 (9th Cir.1995). Because Pinholster filed his federal habeas petition in 1997, the provisions of AEDPA govern his claims. See Penry v. Johnson, 532 U.S. 782, 792, 121 S.Ct. 1910, 150 L.Ed.2d 9 (2001).

AEDPA provides that a petitioner is not entitled to habeas relief on any claim “adjudicated on the merits” by the state court unless that adjudication:

(1) resulted in a decision that was contrary to, or involved an unreasonable application of, clearly established Federal law, as determined by the Supreme Court of the United States; or

(2) resulted in a decision that was based on an unreasonable determination of the facts in light of the evidence presented in the State court proceeding.

28 U.S.C. § 2254(d). The relevant state court decision is the last reasoned decision regarding a claim, Barker v. Fleming, 423 F.3d 1085, 1091 (9th Cir.2005), and “the phrase ‘[adjudicated] on the merits’ requires that the [state court’s] grant or denial rest on substantive, rather than procedural, grounds,” Lambert v. Blodgett, 393 F.3d 943, 966 (9th Cir.2004) (reading in pari materia with 28 U.S.C. § 2254(d)).

“Clearly established” federal law consists of holdings of the Supreme Court at the time the petitioner’s state court conviction became final. Terry Williams v. Taylor, 529 U.S. 362, 379-84, 120 S.Ct. 1495, 146 L.Ed.2d 389 (2000). Habeas relief is unavailable if the Supreme Court has not “broken sufficient legal ground” on a constitutional principle advanced by a petitioner, even if lower federal courts have decided the issue. Id. at 381, 120 S.Ct. 1495. Nevertheless, while only Supreme Court authority is binding, circuit court precedent may be “persuasive” in determining what law is clearly established and whether a state court applied that law unreasonably. Clark v. Murphy, 331 F.3d 1062, 1069 (9th Cir.2003). A state court decision is “contrary to” the Supreme Court’s clearly established precedents if the decision applies a rule that contradicts the governing law set forth in those precedents, thereby reaching a conclusion opposite to that reached by the Supreme Court on a matter of law, or if it confronts a set of facts that is materially indistinguishable from a decision of the Supreme Court but reaches a different result. Terry Williams, 529 U.S. at 405-06, 120 S.Ct. 1495.

Under the “unreasonable application” prong, a federal court may grant relief where a state court “identifies the correct governing legal rule from [the Supreme] Court’s cases but unreasonably applies it to the facts of the particular ... case,” or “unreasonably extends a legal principle from[Supreme Court] precedent to a new context where it should not apply or unreasonably refuses to extend that principle to a new context where it should apply.” Id. at 407, 120 S.Ct. 1495. To show that a state court’s application of Supreme Court precedent was “unreasonable,” the petitioner must establish that the state court’s decision was not merely incorrect or erroneous, but “objectively unreasonable.” Id. at 409-10, 120 S.Ct. 1495.

*663In this case, although both parties agree that AEDPA applies, they disagree over the level of deference owed to the California Supreme Court’s decision in light of its summary nature. Pinholster argues that, because the court found only that there was insufficient evidence to make a prima facie claim for relief and allegedly never reached the actual merits of the claim, we review the court’s decision without deference. The State, by contrast, argues that because the court’s summary denial of Pinholster’s claim was an adjudication on the merits, we apply the usual deference required by AEDPA.

Under our precedent, the California Supreme Court’s denial of Pinholster’s petition for writ of habeas corpus “on the substantive ground that it is without merit,” Pinholster II, 525 F.3d at 754, constitutes a decision on the merits of his federal claim. See Hunter v. Aispuro, 982 F.2d 344, 347-48 (9th Cir.1992) (noting that “the California Supreme Court’s denial of a habeas petition without comment or citation constituted a decision on the merits of the federal claims” (citing Harris v. Superior Court, 500 F.2d 1124, 1127-29 (9th Cir. 1974) (en banc))); Gaston v. Palmer, 417 F.3d 1030, 1038 (9th Cir.2005) (recognizing that “[w]e construe ‘postcard’ denials such as these to be decisions on the merits” (citing Hunter, 982 F.2d at 348)). The Supreme Court has not addressed the question of the proper measure of deference that applies under AEDPA where, as here, a state court provides no rationale for its decision denying habeas relief on the merits, and where, as here, no other state court decision has addressed the claims at issue. We have held, however, that in such situations, we “perform an ‘independent review of the record’ to ascertain whether the state court decision ■was objectively unreasonable.” Himes v. Thompson, 336 F.3d 848, 853 (9th Cir.2003) (quoting Delgado v. Lewis, 223 F.3d 976, 982 (9th Cir.2000)); see also Cooper v. Brown, 510 F.3d 870, 921 (9th Cir.2007); Lewis v. Mayle, 391 F.3d at 996. Such “[ijndependent review of the record is not de novo review of the constitutional issue, but rather, the only method by which we can determine whether a silent state court decision is objectively unreasonable.” Himes, 336 F.3d at 853.4

III. DISCUSSION

Pinholster argues that the California Supreme Court’s summary denial of his Sixth Amendment claims of ineffective assistance of counsel at the guilt and penalty phases of his trial was objectively unreasonable under AEDPA. Because the California Supreme Court issued its last decision in October 1997, we apply, as the relevant “clearly established Federal law” at that time, the Supreme Court’s familiar two-part standard for analyzing ineffective assistance claims set forth in Strickland v. Washington, 466 U.S. 668, 104 S.Ct. 2052, 80 L.Ed.2d 674 (1984). See Terry Williams, 529 U.S. at 391, 120 S.Ct. 1495 (noting that “[i]t is past question that the *664rule set forth in Strickland qualifies as clearly established Federal law, as determined by the Supreme Court of the United States,” and that “[the] Court’s precedent dictated that the Virginia Supreme Court apply the Strickland test at the time that court entertained Williams’ ineffective-assistance claim” (internal quotation marks omitted)).

In doing so, we note that the Court has repeatedly applied Strickland’s ineffective assistance standard to cases where, as here, the trial occurred before Strickland was decided on May 14, 1984.5 In Burger v. Kemp, 483 U.S. 776, 777, 794, 107 S.Ct. 3114, 97 L.Ed.2d 638 (1987), for example, the Court applied the Strickland standard in evaluating trial counsel’s performance where the habeas petitioner was convicted and sentenced to death on January 25, 1978, over six years before Strickland was decided. Additionally, in Woodford v. Visciotti 537 U.S. 19, 21, 22, 123 S.Ct. 357, 154 L.Ed.2d 279 (2003) (per curiam), the Court applied the Strickland standard where the petitioner was convicted and sentenced a year before Strickland was decided, see People v. Visciotti 2 Cal.4th 1, 5 Cal.Rptr.2d 495, 825 P.2d 388 (1992), and where, as here, the petitioner’s ineffective assistance claims were governed by AED-PA, see 537 U.S. at 21, 123 S.Ct. 357.

Given that AEDPA deals only with the state court’s adjudication of a claim, it does nothing to alter the standard of care to which trial counsel is held. At the same time, because Pinholster’s conviction was not final when Strickland was decided, he is entitled to rely on Strickland in challenging his conviction. See Teague v. Lane, 489 U.S. 288, 304-05, 109 S.Ct. 1060, 103 L.Ed.2d 334 (1989); Griffith v. Kentucky, 479 U.S. 314, 328, 107 S.Ct. 708, 93 L.Ed.2d 649 (1987).

To prevail under Strickland, the petitioner must first “show that counsel’s performance was deficient.” 466 U.S. at 687, 104 S.Ct. 2052. To be “deficient,” counsel’s trial performance must be objectively unreasonable “under prevailing professional norms” and under “all the circumstances” of the particular case. Id. at 687-88, 104 S.Ct. 2052. Our inquiry into “counsel’s performance [is] highly deferential,” and “[a] fair assessment of attorney performance requires that every effort be made to eliminate the distorting effects of hindsight, to reconstruct the circumstances of counsel’s challenged conduct, and to evaluate the conduct from counsel’s perspective at the time.” Id. at 689, 104 S.Ct. 2052. Given the “strong presumption that counsel’s conduct falls within the wide range of reasonable professional assistance,” the petitioner carries the burden of showing that the challenged action could not be viewed as sound trial strategy. Id.

“Second, the [petitioner] must show that the deficient performance prejudiced the defense.” Id. at 687, 104 S.Ct. 2052. For us to find prejudice, “[i]t is not enough for the [petitioner] to show that the errors had some conceivable effect on the outcome of the proceeding.” Id. at 693, 104 S.Ct. 2052. “On the other hand, ... [the petitioner] need not show that counsel’s deficient conduct more likely than not altered the outcome in the ease.” Id. Rather, “[t]he [petitioner] 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.” Id. at 694, 104 S.Ct. 2052.

Following AEDPA’s enactment, the Supreme Court has reiterated that we apply a “case-by-case approach to determining *665whether an attorney’s performance was unconstitutionally deficient under Strickland.” Rompilla v. Beard, 545 U.S. 374, 393-94, 125 S.Ct. 2456, 162 L.Ed.2d 360 (2005) (O’Connor, J., concurring). In doing so, however, the Court has instructed that its post-AEDPA ineffective assistance of counsel decisions are clearly relevant for the purpose of informing the interpretation and application of the standards originally announced in Strickland.

In Wiggins v. Smith, for example, where the petitioner’s trial originally took place in 1989, the Court observed that “[o]ur opinion in [Terry ] Williams ... is illustrative of the proper application of [Strickland’s] standards.” 539 U.S. 510, 514, 522, 123 S.Ct. 2527, 156 L.Ed.2d 471 (2003). The Wiggins Court explained that “[w]hile [Terry] Williams had not yet been decided at the time the Maryland Court of Appeals rendered the decision at issue in [Wiggins ],” the Court’s reliance on Terry Williams was nonetheless proper because “Williams’ case was before [the Court] on habeas review,” and because the Court “made no new law in resolving Williams’ ineffectiveness claim” but merely applied the established holding in Strickland. Id. at 522, 123 S.Ct. 2527. The Wiggins Court thus reached its conclusion that counsel rendered ineffective assistance under Strickland in part by distinguishing the facts in Wiggins from those in Terry Williams:

[I]n contrast to the petitioner in Williams ..., Wiggins does not have a record of violent conduct that could have been introduced by the State to offset this powerful mitigating narrative. As the Federal District Court found, the mitigating evidence in this case is stronger, and the State’s evidence in support of the death penalty far weaker, than in Williams, where we found prejudice as the result of counsel’s failure to investigate and present mitigating evidence.

539 U.S. at 537-38, 123 S.Ct. 2527 (citation omitted). Similarly, in Rompilla, decided in 2005, the Court repeatedly cited Terry Williams and Wiggins in reversing an ineffective assistance case in which the state trial took place in 1988 and in which the state postconviction decision issued in 1998. See Rompilla, 545 U.S. at 378-93, 387 n. 7, 125 S.Ct. 2456; Commonwealth v. Rompilla, 539 Pa. 499, 653 A.2d 626, 628 (1995). Most recently, in Porter v. McCollum, the Court relied on post-AEDPA cases in determining the “prevailing professional norms” at the time of Porter’s trial in 1988. 558 U.S. -, 130 S.Ct. 447, 452, — L.Ed.2d - 9-10 (2009) (per curiam).

Thus, we hold that we are required to apply the instructions contained in the Supreme Court’s post-AEDPA ineffective assistance of counsel cases to inform and construe the meaning of Strickland as it applies to Pinholster’s trial and postconviction proceedings. In other words, Terry Williams, Wiggins, Rompilla, and Porter help illuminate which applications of Strickland are unreasonable under AED-PA.

A. The Guilt Phase

Our three-judge panel unanimously held that, even assuming that counsel’s representation at the guilt phase of the trial constituted deficient performance, the district court properly denied an evidentiary hearing and granted summary judgment in favor of the State because Pinholster failed to make a colorable showing of prejudice. Pinholster II, 525 F.3d at 757, 761, 775, 777; see also Strickland, 466 U.S. at 697, 104 S.Ct. 2052 (stating that a court may assume ineffective assistance to resolve a claim on the basis of prejudice). We reach the same conclusion, and adopt Judge *666Fisher’s discussion as to prejudice in the full paragraph at Pinholster II, 525 F.3d at 777, which best summarizes the panel’s prejudice holding. We find no useful purpose would be served by repeating extensive work already contained in the Federal Reporter. On these grounds, we affirm the district court’s denial of Pinholster’s request for an evidentiary hearing and denial of habeas relief on his claim of ineffective assistance of counsel at the guilt phase.

B. The Penalty Phase

In its appeal, the State argues that the California Supreme Court was not objectively unreasonable in summarily denying Pinholster’s claim that his attorneys rendered ineffective assistance at the penalty phase of his trial by failing to investigate, to discover, and to introduce readily available mitigation evidence. For the following reasons, and based on our independent review of the record, we disagree. See Himes, 336 F.3d at 853.

1. Federal Evidentiary Hearing

The State contends that the district court abused its discretion in granting Pinholster a federal evidentiary hearing on his penalty phase ineffective assistance claim because the court allegedly failed to consider whether Pinholster properly developed a factual basis for the claim in the California Supreme Court. As a result, the State argues, the district court improperly reached its decision to grant habeas relief based on evidence that was not before the state court.

The State’s contention regarding the federal evidentiary hearing is unavailing. The State is correct that when a petitioner challenges a state habeas court’s factual conclusions, the relevant evidence is restricted to that presented to the state habeas court: Under AEDPA, federal post-conviction relief is available on such claims only if the state habeas court’s adjudication “resulted in a decision that was based on an unreasonable determination of the facts in light of the evidence presented in the State court proceeding.” 28 U.S.C. § 2254(d)(2) (emphasis added).

Here, however, Pinholster challenges the California Supreme Court’s legal conclusions. Such claims are governed not by § 2254(d)(2), but by § 2254(d)(1). As noted above, under § 2254(d)(1), relief is available if the state habeas court’s adjudication “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.” Significantly, Congress omitted “in light of the evidence presented in the State court proceeding” from § 2254(d)(1), while including that language in § 2254(d)(2). This omission strongly indicates that Congress did not intend to restrict the inquiry under § 2254(d)(1) only to the evidence introduced in the state habeas court, or to have federal courts imply any such restriction.

In addition, AEDPA has an independent provision that expressly restricts a habeas petitioner’s ability to introduce new evidence in federal court. See 28 U.S.C. § 2254(e)(2). That restriction applies when the petitioner was not diligent in seeking to develop the new evidence in state court. Holland v. Jackson, 542 U.S. 649, 652-53, 124 S.Ct. 2736, 159 L.Ed.2d 683 (2004). Neither § 2254(d)(1) nor § 2254(e)(2) contains any language indicating that evidence properly introduced under § 2254(e)(2) is irrelevant when applying § 2254(d)(1). On the contrary, § 2254(e)(2) establishes that, when drafting AEDPA, Congress was aware that federal habeas petitioners sometimes rely on evidence not presented in the state habeas court, and that Congress responded to that *667issue with an explicit statutory restriction on the introduction of such evidence.

The legal backdrop against which Congress drafted and enacted AEDPA also informs our construction of § 2254(d)(1). Historically, a federal habeas petitioner could rely on new evidence as long as that evidence did not so alter the underlying claims as to render them unexhausted. Vasquez v. Hillery, 474 U.S. 254, 260, 106 S.Ct. 617, 88 L.Ed.2d 598 (1986). As § 2254(e)(2) demonstrates, Congress included specific language in AEDPA when it intended to change that traditional practice. Congress’s failure to include any such language in § 2254(d)(1), by contrast, demonstrates that Congress did not intend for § 2254(d)(1) to imply any additional departure from the Vasquez rule beyond that contained in § 2254(e)(2).

Supreme Court precedent also fails to support the State’s position on this issue. In Michael Williams — the Court’s most significant decision regarding evidentiary development in federal habeas proceedings under AEDPA — the Court did not tie the right to a federal evidentiary hearing to a prior determination that the state habeas court had unreasonably applied Supreme Court law to the record before it. Michael Williams v. Taylor, 529 U.S. 420, 120 S.Ct. 1479, 146 L.Ed.2d 435 (2000). Nor did the Court indicate that evidence introduced at a properly conducted federal evidentiary hearing must be disregarded unless the federal court has already concluded that the state habeas court decision involved an unreasonable application of Supreme Court law. See id. at 437-44, 120 S.Ct. 1479. The clear import of Michael Williams is, to the contrary, that any new evidence admissible either under § 2254(e)(2) or because the petitioner did not exhibit a lack of diligence in state court, is pertinent to the petitioner’s claims under AEDPA.

Similarly, in Holland, a case governed by § 2254(d)(1), although the Court explained that a state habeas court’s decision generally must be reviewed in light of the evidence presented at the state habeas proceeding, the Court immediately thereafter noted that a federal habeas petitioner can introduce new evidence if he “was not at fault in failing to develop that evidence in state court.” 542 U.S. at 652-53, 124 S.Ct. 2736 (citing Michael Williams, 529 U.S. at 431-37, 120 S.Ct. 1479). As in Michael Williams, nowhere did the Holland Court indicate that such new evidence should be ignored absent an earlier determination of unreasonableness under § 2254(d)(1).6 To the contrary, the Court first concluded that the new evidence presented by the petitioner during the federal habeas proceedings was not admissible under Michael Williams or § 2254(e)(2), and only then concluded that the state habeas court’s decision was reasonable under § 2254(d)(1). Holland, 542 U.S. at 652-53, 124 S.Ct. 2736.

Bradshaw v. Richey also suggests that the reasonableness of a state habeas court’s decision under § 2254(d)(1) should be considered only after determining what evidence is admissible under Michael Williams and § 2254(e)(2). 546 U.S. 74, 79, 126 S.Ct. 602, 163 L.Ed.2d 407 (2005). Bradshaw faulted the Sixth Circuit for “relying on evidence that was not properly presented to the state habeas courts without first determining (1) whether respondent was at fault for failing to develop the factual basis for his claims in state court, or (2) whether respondent satisfied the criteria established by 28 U.S.C. *668§ 2254(e)(2).” 546 U.S. at 79, 126 S.Ct. 602 (citing Michael Williams, 529 U.S. at 430-32, 120 S.Ct. 1479). As in both Michael Williams and Holland, the Bradshaw Court nowhere indicated that the Sixth Circuit should have first considered the state habeas court’s decision in light of the evidence produced in the state habeas proceeding, then considered whether the new evidence was admissible, and only then considered whether that new evidence warranted relief.

Given AEDPA’s statutory text and the Supreme Court’s governing precedent, the most reasonable approach to any new evidence introduced in federal habeas proceedings is the most straightforward: Section 2254(e)(2) restricts the evidence that may be considered in federal habeas proceedings, and § 2254(d)(1) contains no additional restrictions on the relevant evidence. If the evidence is admissible under Michael Williams or § 2254(e)(2), and if it does not render the petitioner’s claims unexhausted under Vasquez, then it is properly considered in evaluating whether the legal conclusion reached by the state habeas court was a reasonable application of Supreme Court law.

Importantly, here, the district court expressly found that Pinholster had met the requirements for an evidentiary hearing under AEDPA. In the addendum to its order granting habeas relief on Pinholster’s penalty phase ineffective assistance claim, the district court stated, in relevant part:

Under ... AEDPA, a petitioner is not entitled to an evidentiary hearing if he failed to develop the factual basis of a claim in state court. 28 U.S.C. § 2254(e)(2). “[A] failure to develop the factual basis of a claim is not established unless there is lack of diligence, or some

greater fault, attributable to the prisoner or the prisoner’s counsel.” [Michael] Williams v. Taylor, 529 U.S. 420, 432, 120 S.Ct. 1479, 146 L.Ed.2d 435 (2000). “Diligence for purposes of the opening clause depends upon whether the prisoner made a reasonable attempt, in light of the information available at the time, to investigate and pursue claims in state court; it does not depend ... upon whether those efforts could have been successful.” Id. at 435 [120 S.Ct. 1479]. “Diligence will require in the usual case that the prisoner, at a minimum, seek an evidentiary hearing in state court in the manner prescribed by state law.” Id. at 437 [120 S.Ct. 1479].

Pinholster sought an evidentiary hearing in state court regarding his claim that counsel was ineffective for failing to investigate and present mitigating evidence at the penalty phase. He did not fail to develop the factual basis of this claim in state court and an evidentiary hearing was appropriate.

Based upon our independent inquiry, we cannot say that the district court erred in its analysis. See Holland, 542 U.S. at 653, 124 S.Ct. 2736 (noting that in addition to the district court’s failure to make the requisite findings for an evidentiary hearing, the Sixth Circuit also failed to “independently inquire into these matters”). Pinholster exercised diligence in pursuing an evidentiary hearing in state court regarding his mitigation ineffective assistance claim. By withdrawing its order to show cause and dismissing Pinholster’s habeas petition on the merits, the state court denied Pinholster any further opportunity to develop the factual record in state court. Because Pinholster was diligent, the limitations of 28 U.S.C. § 2254(e)(2) are inapplicable. See Holland, 542 U.S. at 653, 124 S.Ct. 2736.7

*669Moreover, even if those limitations did apply, we find that both the federal and the state habeas petitions detail many substantially identical facts, including trial counsel’s failure to file a motion for a continuance to prepare a mitigation case for the penalty phase, counsel’s introduction of Brashear’s testimony, Pinholster’s home life as a child, and Pinholster’s educational, medical, social, psychological, and family background. Although Pinholster substituted experts during the proceedings who ultimately developed different mental impairment theories, these experts nonetheless relied on the same background facts that Pinholster presented to the state court. Accordingly, if § 2254(e)(2) were to limit the scope of the evidence before us, it would exclude only the new mental impairment theories introduced in federal court, and their exclusion would not affect our result.

We therefore conclude that the mitigation evidence introduced at the federal evidentiary hearing is properly before us in considering Pinholster’s penalty phase ineffective assistance claim. For the same reasons, and because the facts adduced at the evidentiary hearing have not fundamentally altered the penalty phase ineffective assistance claim that the California Supreme Court already considered, we also hold that Pinholster has properly exhausted this claim. See Weaver v. Thompson, 197 F.3d 359, 364 (9th Cir.1999) (rejecting an exhaustion challenge as “unwarranted hairsplitting” where at each step of the habeas proceedings the legal claim remained the same, but the precise factual predicate changed after the evidentiary hearing).

2. Deficient Performance

In Strickland, the Court held that “counsel has a duty to make reasonable investigations or to make a reasonable decision that makes particular investigations unnecessary. In any ineffectiveness case, a particular decision not to investigate must be directly assessed for reasonableness in all the circumstances, applying a heavy measure of deference to counsel’s judgments.” 466 U.S. at 691, 104 S.Ct. 2052. Strickland also instructs that “[t]he proper measure of attorney performance [is] reasonableness under prevailing professional norms.” Id. at 688, 104 S.Ct. 2052. As one example of a “guide[] to determining what is reasonable,” the Court referenced “[prevailing norms of practice as reflected in American Bar Association standards.” Id.; see also Rompilla, 545 U.S. at 387, 125 S.Ct. 2456 (“[W]e long have referred [to these ABA Standards] as guides to determining what is reasonable.” (citation and internal quotation marks omitted) (alterations in original)).

At the time of Pinholster’s trial in 1984, the ABA standards in place recognized that counsel in capital cases had a duty to *670investigate thoroughly the client’s background and the circumstances of the case in an effort to uncover mitigating evidence relevant to the penalty phase defense:

It is the duty of the lawyer to conduct a prompt investigation of the circumstances of the case and to explore all avenues leading to facts relevant to the merits of the case and the penalty in the event of conviction. The investigation should always include efforts to secure information in the possession of the prosecution and law enforcement authorities. The duty to investigate exists regardless of the accused’s admissions or statements to the lawyer of facts constituting guilt or the accused’s stated desire to plead guilty.

Rompilla, 545 U.S. at 387, 125 S.Ct. 2456 (quoting 1 ABA Standards for Criminal Justice 4-4.1 (2d ed. 1982 Supp.)). This duty has been unequivocally recognized by the Supreme Court, which recently held that “[i]t is unquestioned that under the prevailing professional norms at the time of [Pinholster’s] trial, counsel had an ‘obligation to conduct a thorough investigation of the defendant’s background.’ ” Porter, 130 S.Ct. at 453 (quoting Terry Williams, 529 U.S. at 396, 120 S.Ct. 1495 (citing 1 ABA Standards for Criminal Justice 4-4.1, commentary, 4-55 (2d ed. 1980))); see also Wiggins, 539 U.S. at 524, 123 S.Ct. 2527 (“The lawyer also has a substantial and important role to perform in raising mitigating factors both to the prosecutor initially and to the court at sentencing.... Investigation is essential to fulfillment of these functions.” (quoting 1 ABA Standards for Criminal Justice 4-4.1, commentary, 4-55 (2d ed. 1982)) (emphasis added)).

Since 1984 — and in reliance on the same ABA Standards in place at the time of Pinholster’s trial — the Court has elaborated that Strickland’s duty to investigate requires that counsel “present[] and explain[ ] the significance of all the available [mitigation] evidence.” Terry Williams, 529 U.S. at 399,120 S.Ct. 1495. The Court has also found ineffective assistance where, “[d]espite these well-defined norms” articulated in the ABA Standards, “counsel abandoned their investigation of [the] petitioner’s background after having acquired only rudimentary knowledge of his history from a narrow set of sources.” Wiggins, 539 U.S. at 524,123 S.Ct. 2527.

The dissent labors to convince us that Bobby v. Van Hook, 558 U.S. -, 130 S.Ct. 13, 175 L.Ed.2d 255 (2009), somehow changed the rules with regard to the ABA standards. Diss. at 690-95. However, the Court held that it is permissible to use a restatement of professional standards to help determine an attorney’s obligation towards a client only when those standards “describe the professional norms prevailing when the representation took place.” Van Hook, at 16. That is precisely what we do here. We refer to the 1982 edition of the ABA standards that were in effect at the time of Pinholster’s 1984 trial. Moreover, in Van Hook, the Sixth Circuit erroneously stated that attorneys “must fully comply” with the ABA guidelines. Id. (citing Van Hook v. Anderson, 560 F.3d 523, 526 (6th Cir.2009)). Here we make clear, as the Supreme Court has, that such standards do not define reasonable representation, but rather are “guides to determining what is reasonable.” Strickland, 466 U.S. at 688, 104 S.Ct. 2052. The dissent’s jeremiad is therefore misplaced.

In Porter, the Supreme Court found that the counsel’s investigation “clearly did not satisfy” the aforementioned professional norms. 130 S.Ct. at 453. Porter’s counsel met with him only once to discuss the penalty phase and did not obtain school, medical, or military records that counsel *671should have known would have led to significant mitigating evidence. Id. The Court also rejected counsel’s excuse that Porter was “fatalistic and uncooperative.” Id.8

Similarly, the evidence here shows that Pinholster’s trial counsel completely failed to discharge their responsibility to conduct the investigation required under Strickland. One week before the penalty hearing, counsel told the judge that they “did not prepare a case in mitigation” because they “felt there would be no penalty phase hearing.” Notwithstanding counsel’s admission, they inexplicably declined to request a continuance — even though the judge indicated he would readily grant one — because they did not believe the extra time “would make a great deal of difference.” Billing records confirm counsel’s own admissions that they spent almost no time preparing for the penalty phase hearing that would determine whether Pinholster would live or die.

At the penalty phase hearing, counsel waived their opening statement and presented only one witness, Pinholster’s mother, Brashear, whose testimony the district court aptly described as “brief ... damaging, incomplete, and inaccurate.” Brash-ear testified about Pinholster’s head injuries as a child as well as his epilepsy, but because the jurors lacked any accompanying expert testimony to explain the ramifications of those conditions they were left without the ability to make informed judgments about that evidence. Trial counsel also failed to obtain any of the readily available medical, psychological, law enforcement, or school records for Pinholster or his siblings. Consequently, when they asked their retained psychiatrist, Dr. Stalberg — whom they hired only after the trial started — about the availability of mitigation evidence, they failed to provide him with materials that were necessary for him to make an informed determination.

The dissent disparages these damaging admissions. Rather than concede the lawyer’s admissions, the dissent employs pop-linguistics to argue that what Brainard really meant when he said he did not recall conducting a reasonable investigation was that he actually did conduct a reasonable investigation. Diss. at 701-02. The dissent also makes much of the fact that the admissions were made after the trial, id. at 702, 706-07, but the Supreme Court’s recent decision in Porter relied heavily on the counsel’s post-conviction admission that he “had only one short meeting with Porter regarding the penalty phase ... and that [h]e did not obtain any of Porter’s school, medical, or military service records or interview any members of Porter’s family.” 130 S.Ct. at 453. The Court clearly does not share the dissent’s notion that post-conviction admissions by legal counsel do not count because attorneys are apt to lie. Diss. at 701 n.10.

Here, counsel’s performance was far more deficient than that of the attorneys in Terry Williams, Wiggins, and Rompilla, where in each case the Supreme Court upheld the petitioner’s ineffective assistance claim. In Terry Williams, “[t]he record established] that counsel did not begin to prepare for th[e] [penalty] phase of the proceeding until a week before the trial,” that counsel had called only a total *672of four witnesses, and that if counsel had not “failed to conduct an investigation];,] th[ey] would have uncovered extensive records graphically describing Williams’ nightmarish childhood.” 529 U.S. at 369, 395, 120 S.Ct. 1495. In addition, in Wiggins, “[a]t no point did [counsel] proffer any evidence of petitioner’s life history or family background,” nor did counsel “expand their investigation beyond the PSI [Presentence Investigation Report] and the DSS [Department of Social Services] records.” 539 U.S. at 516, 524, 123 S.Ct. 2527. Finally, in Rompilla, counsel called five of Rompilla’s family members as witnesses at the penalty phase and examined the reports of three mental health witnesses, but failed to review any of the materials in the court file on Rompilla’s prior conviction, despite knowledge of the prosecution’s intention to introduce those materials at trial. See 545 U.S. at 381-86, 125 S.Ct. 2456.

Pinholster’s trial counsel performed even less review of the readily available records than did the lawyer in Wiggins, who reviewed both the PSI report and the DSS records before the penalty phase. Moreover, similar to counsel in Terry Williams, Pinholster’s attorneys spent less than a week preparing for the penalty phase, but in Pinholster’s ease, the preparation lasted less than an average workday. Also, while the lawyers in both Terry Williams and Rompilla performed deficiently even though they interviewed and called multiple witnesses at the penalty phase, Pinholster’s counsel interviewed and presented just one witness, whose testimony was not only misleading, but also self-serving and harmful to Pinholster’s defense.

Nor, as the district court properly found, were counsel’s actions the result of any kind of reasonable strategic decision. Instead, counsel mistakenly thought that there would be no penalty phase at all, because the State had allegedly failed to provide notice of its intent to introduce aggravating evidence. As previously noted, however, the state trial court held a hearing on that issue and determined that the State had served Pinholster with adequate notice during the period in which he represented himself pre-trial. Nevertheless, even after learning of their mistake, counsel declined the court’s invitation to move for a continuance to prepare for the penalty phase, stating on the record that they did not believe the extra time “would make a great deal of difference.”9 Such an uninformed decision cannot, by any reasonable stretch of the imagination, “be considered sound trial strategy.” See Strickland, 466 U.S. at 689, 104 S.Ct. 2052.

In exactly such an unreasonable stretch, our dissenting colleague demonstrates yet again why he would be such a talented writer of fiction. He concocts a fantastical trial strategy for Pinholster’s attorneys despite their own admissions that they were simply unprepared. Counsel told the trial judge a week before the penalty hearing— much too soon for them to be “falling on their swords” — that they had not prepared a mitigation case.10 Diss. at 701 n.10. The *673truth of that claim was borne out a week later. To give attorneys the benefit of the doubt is one thing, but to fabricate an excuse that the attorneys themselves could not conjure up is another. The dissent suggests that counsel appeared so ineffective that they must have had something sinister in mind; in other words, no one could be that incompetent. However, given that counsel claimed to be unprepared for the penalty phase, rejected the offer of additional time to prepare, presented only one devastating “mitigation” witness, and secured their client a death sentence, it is obvious that they were not merely being sneaky; they were incompetent, and they failed miserably to discharge the duties they owed to their client at the penalty phase of his murder trial.

To be sure, in some cases counsel may have “sound reason to think it would have been pointless to spend time and money on ... additional investigation,” thereby rendering counsel’s failure to discover additional mitigating evidence reasonable. See Rompilla, 545 U.S. at 383, 125 S.Ct. 2456; see also, e.g., Burger, 483 U.S. at 792-95, 107 S.Ct. 3114 (finding “counsel’s decision not to mount an all-out investigation into petitioner’s background in search of mitigating circumstances” reasonable where all potential witnesses brought to his attention provided information predominantly harmful to the defense). But such decisions are reasonable only because counsel made them after an investigation adequate enough to make an informed choice. See Wiggins, 539 U.S. at 527, 123 S.Ct. 2527 (“Strickland does not establish that a cursory investigation automatically justifies a tactical decision with respect to sentencing strategy. Rather, a reviewing court must consider the reasonableness of the investigation said to support that strategy.”); Duncan v. Ornoski 528 F.3d 1222, 1234 (9th Cir.2008) (interpreting Strickland to mean that “decisions that are made before a complete investigation is conducted are reasonable only if the level of investigation was also reasonable”), cert. denied, — U.S. -, 129 S.Ct. 1614, 173 L.Ed.2d 1001 (2009); Correll v. Ryan, 539 F.3d 938, 948 (9th Cir.2008) (“A decision by counsel not to present mitigating evidence cannot be excused as a strategic decision unless it is supported by reasonable investigations.”); Jennings v. Woodford, 290 F.3d 1006, 1014 (9th Cir.2002) (“Although defense counsel is empowered to make such strategic decisions, Strickland demands that such decisions be reasonable and informed.”).

Here, defense counsel conducted no investigation into Pinholster’s background at all, aside from interviewing his mother. Not only was counsel’s investigation grossly inadequate; they also failed to look into any of the limited mitigating evidence that they did discover in their interview with Pinholster’s mother, such as the evidence of Pinholster’s epilepsy. Since Pinholster’s counsel did not even attempt a meaningful investigation, we can see no basis for concluding that they could have had any “sound reason” to believe that “additional investigation,” see Rompilla, 545 U.S. at 383, 125 S.Ct. 2456 (emphasis added), would not have, as they termed it, “ma[d]e a great deal of difference.”

Finally, the State’s attempt to excuse counsel’s failure to conduct the requi*674site investigation because Pinholster allegedly told them “not to put on a penalty defense” fails. As noted, this approach has been rejected by the Supreme Court. See Porter, 130 S.Ct. at 453. Furthermore, in support of this assertion, the State relies on an interview report written by a defense investigator in July 1991. However, as the district court noted, because neither Pinholster nor the defense investigator testified at the evidentiary hearing, this statement is hearsay.11 Regardless of its truth, the record demonstrates that the statement did not influence trial counsel’s performance, because trial counsel did present a penalty defense, albeit a constitutionally defective one. Moreover, even assuming that the statement is true, it did not relieve counsel of their constitutional duty to investigate. “A defendant’s insistence that counsel not call witnesses at the penalty phase does not eliminate counsel’s duty to investigate mitigating evidence or to advise the defendant of the potential consequences of failing to introduce mitigating evidence, thereby assuring that the defendant’s decision regarding such evidence is informed and knowing.” Williams v. Woodford, 384 F.3d 567, 622 (9th Cir.2004). Here, the State has failed to present any evidence that Pinholster was counseled concerning the possible repercussions of not introducing mitigation evidence, thereby enabling him to make any kind of informed, knowing decision on the matter. Counsel’s admissions on the record instead reflect that they simply failed to prepare a mitigation case because they did not expect a penalty phase to occur, and then, out of apparent apathy or neglect of duty, declined a continuance without an informed or strategic basis for doing so.

It is prima facie ineffective assistance for counsel to “abandon[] their investigation of [the] petitioner’s background after having acquired only rudimentary knowledge of his history from a narrow set of sources.” Wiggins, 539 U.S. at 524-25, 123 S.Ct. 2527; see also Siripongs v. Calderon, 35 F.3d 1308, 1316 (9th Cir.1994) (holding that counsel performed deficiently by failing to “conduct more than a cursory investigation” and by making “no attempt to humanize [the defendant] before the jury”). Accordingly, we hold that counsel’s almost complete failure to investigate the readily available mitigation evidence in Pinholster’s case was objectively unreasonable under both the prevailing norms of practice, as reflected in the ABA Standards in place at the time of his trial, as well as the clearly established federal law in Strickland.

3. Prejudice

We also hold that trial counsel’s constitutionally deficient performance prejudiced Pinholster’s defense. See Strickland, 466 U.S. at 687, 104 S.Ct. 2052. As noted, to demonstrate prejudice, a petitioner “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.” Id. at 694,104 S.Ct. 2052.

Regarding prejudice at capital sentencing, “the question is whether there is a reasonable probability that, absent the errors, the sentencer ... would have concluded that the balance of aggravating and mitigating circumstances did not warrant death.” Id. at 695, 104 S.Ct. 2052. This inquiry requires us to “reweigh the evidence in aggravation against the totality of *675available mitigating evidence.” Wiggins, 539 U.S. at 534, 123 S.Ct. 2527. The “totality of the available mitigation evidence” includes “both that adduced at trial, and the evidence adduced in the habeas proceeding[s].” Terry Williams, 529 U.S. at 397, 120 S.Ct. 1495. More particularly, given California’s requirement that a unanimous jury impose any death sentence, see Cal. Penal Code § 190.4(b), our inquiry is whether, based on the sum of this evidence, “there is a reasonable probability that at least one juror would have struck a different balance,” Wiggins, 539 U.S. at 537,123 S.Ct. 2527 (emphasis added).

a. Aggravating Evidence

As the district court noted, there was substantial aggravating evidence in this case. The State presented evidence that Pinholster beat both of the murder victims, stabbed one of them with a knife, and took their wallets, all for a paltry gain of $23 and a quarter-ounce of marijuana. Yet, when Pinholster took the stand at trial, he denied murdering the victims and boasted that he had committed hundreds of robberies over the previous six years, using a gun, but never a knife, to victimize drug dealers. He was also openly disrespectful of the deputy prosecutor, appeared unconcerned with the seriousness of the underlying murders, and even laughed or smirked several times during the deputy prosecutor’s cross-examination.

In addition, the State introduced evidence of Pinholster’s earlier conviction for kidnapping with a knife, of his threat to kill the State’s lead witness, and of his assault of another individual with a straight razor. Pinholster had a history of other violent outbursts as well, including striking a bailiff after a court proceeding, resisting arrest and assaulting several police officers, and once, during an apparent epileptic seizure, hitting his wife and breaking her jaw. The jury also heard evidence of Pinholster’s juvenile gang activities and of his substantial disciplinary record at the Los Angeles County Central Jail, where his numerous infractions encompassed throwing urine at guards, threatening and assaulting guards, and initiating fights with other inmates. As a result of this behavior, jail officials classified him as a disciplinary problem and gave him a low-calorie diet reserved for the most recalcitrant inmates.

b. Available Mitigation Evidence

Although the State’s aggravating evidence was severely detrimental to Pin-holster’s case, the record reflects that the harmful effect of that evidence could have been significantly mitigated had Pinholster’s trial counsel performed competently. Instead, the only mitigation evidence introduced by defense counsel at the penalty phase was the inaccurate, damaging testimony of Pinholster’s mother, Brashear. If counsel had conducted even a minimally adequate investigation, however, they would have found a trove of additional mitigation evidence that would have humanized Pinholster to the jury and, at the same time, contradicted Brashear’s misleading version of events. This omitted, but readily available, evidence also would have done much to counter the State’s aggravating evidence, which Brashear’s testimony failed to rebut or even address.

i. Organic Brain Damage

First, counsel would have discovered evidence of the organic basis for Pinholster’s mental health troubles that developed as a result of his traumatic childhood head injuries. During the penalty phase, Brashear testified that when Pinholster was two, she injured his head “quite badly” when she accidentally ran over him with her car. The accident nearly tore off one of his *676ears. She also testified that, when he was four or five, she had a car accident in which his head went through the windshield. Pinholster’s counsel, however, failed to present any medical evidence regarding the consequences of those injuries. As a result, the State argued to an uninformed jury that these injuries were insignificant:

He was run over by a car when he was three years old. That’s very unfortunate. There is no evidence of any brain damage. A lot of children get dropped, fall from their cribs or whatever. A couple of years later he went through a car window, not hospitalized, got medical care.

In addition, Brashear wrongly testified that Pinholster’s epilepsy began after a severe beating that he incurred in jail at the age of eighteen. She then changed her story and claimed that she discovered his epilepsy by witnessing the end of a seizure, at which point he told her about his condition. Given her confusing testimony, however, the State argued at the end of the penalty phase that Pinholster did not have epilepsy at all. The State also argued to the jury that if Pinholster truly had epilepsy, “a doctor would have been brought in to tell you that. Medical records, something.” In contrast, readily available mitigation evidence would have shown that Pinholster’s childhood injuries likely had long-term effects on his mental health.

The evidence demonstrates beyond a doubt that Pinholster suffered from epilepsy from a young age. Pinholster was first diagnosed with epilepsy and treated with anti-seizure medication when he was only nine years old, and he frequently suffered complex partial and grand mal seizures thereafter. Dr. Olson concluded that the two car accidents damaged the frontal lobes of Pinholster’s brain, an injury that frequently causes impulsive behaviors. This damage, Dr. Olson explained, was evidenced both by Pinholster’s epilepsy and by his abnormal EEG reading as a child.12 Dr. Vinogradov similarly concluded that Pinholster’s childhood head injuries resulted in organic, pre-frontal brain damage that changed his personality and explained his aggressive, violent, and antisocial behavior, while Dr. Stalberg characterized the injuries as possibly “devastating” and likewise connected them to Pinholster’s epilepsy.

This additional medical evidence would have helped counter the State’s aggravation case in three respects. First, evidence that Pinholster’s brain damage may have influenced, or even caused, his behavior at the time of the crime may have led jurors to conclude that he was less morally culpable at the time of the offense, and at least one juror may have been inclined to refrain from voting in favor of a capital sentence. See Wiggins, 539 U.S. at 537, 123 S.Ct. 2527 (holding that prejudice is established if “there is a reasonable probability that at least one juror would have struck a different balance” between life and death). Evidence of organic brain injury in other cases has led juries to consider whether because a defendant’s “behavior was physically compelled ... his moral culpability would have been reduced.” Caro v. Woodford, 280 F.3d 1247, *6771257-58 (9th Cir.2002). For this reason, evidence of serious mental health problems, including organic brain damage, is “precisely the type of evidence that we have found critical for a jury to consider when deciding whether to impose a death sentence.” Douglas v. Woodford, 316 F.3d 1079, 1090 (9th Cir.2003). Here, as in Porter, it “was not reasonable to discount entirely the effect that [a psychiatrist’s] testimony might have had on the jury or the sentencing judge.” 130 S.Ct. at 455.

Second, properly presented evidence of Pinholster’s brain injury, and its profound effect on his behavior, could have altered the jury’s impressions of his detrimental guilt phase testimony and of his boastful, disrespectful demeanor by indicating an organic basis for his inappropriate expressions and for his tendency to exaggerate his past. In this way, “in the hands of a competent attorney,” the harmful evidence provided by Pinholster’s trial testimony and by his offensive manner could actually “have been used to support[his] claims of dysfunctional upbringing and continuing mental disorder.” See Correll, 539 F.3d at 955.

Third, evidence of Pinholster’s organic brain injury would have humanized him in the eyes of the jury, even if the jury concluded that his brain injury was not responsible for his actions during his commission of the crime. It is not necessary that there be a direct causal connection between a defendant’s brain injury and the crime he commits for the existence of that injury to serve as a humanizing and therefore mitigating factor during sentencing. See, e.g., Skipper v. South Carolina, 476 U.S. 1, 4-5, 106 S.Ct. 1669, 90 L.Ed.2d 1 (1986) (“Although it is true that [the evidence] would not relate specifically to petitioner’s culpability for the crime he committed, there is no question but that such [evidence] would be mitigating in the sense that [it] might serve as a basis for a sentence less than death.” (citations and quotation marks omitted)). The very existence of organic neurological problems may serve as mitigating evidence at sentencing by eliciting sympathy or, at the very least, some degree of understanding from the sentencer. See Douglas, 316 F.3d at 1090; see also Hendricks v. Calderon, 70 F.3d 1032, 1043 (9th Cir.1995) (holding that mental health evidence could be mitigating at the penalty phase “even though it is insufficient to establish a legal defense to conviction in the guilty phase”). Though the dissent mocks the fact that counsel did not attempt to humanize Pin-holster, diss. at 692, the Supreme Court clearly considers humanizing an important part of penalty-phase mitigation in a death penalty case. See Porter, at 454 (“The judge and jury at Porter’s original sentencing heard almost nothing that would humanize Porter or allow them to accurately gauge his moral culpability.”).

ii. Abusive and Deprived Childhood

Second, if counsel had conducted an adequate investigation, they would have found evidence of Pinholster’s abusive and deprived upbringing. Brashear minimized and distorted the true nature of Pinholster’s relationship with his step-father when she testified at the penalty phase:

Q: Did he get along with his stepfather, Mrs. Brashear? I am sorry, I know this is difficult for you.

A: Well, at times. He would try to discipline him and sometimes I was objectionable to that. Scott has always— he had a mind of his own.

Q: Do you feel that any of that punishment that was given to Scott was abusive or near abusive?

A: Well, I think so at times. Scott would push to the limit. He was a boy *678that — he had his own way. My husband sometimes would lose his temper with him, yes. He always thought he was punishing him to make him see that wasn’t the thing he was supposed to be doing, and Scott rebelled even when he was quite young. We got in quite a bit of arguments and hassles.

Q: What kind of relationship does Scott have with his stepfather today?

A: Well, it’s okay. He just feels very bad for what has happened to Scott. Q: But is it a friendly relationship?

A: Yes.

In stark contrast, the additional mitigation evidence showed that Pinholster suffered violent and continuous physical abuse during his early years. His brother, Terry, described this abuse as follows:

[Our step-father] frequently beat Scott while Scott was a child; these beatings continued until Scott left our home. Bud would use his fists, a belt, or anything else available, including on at least one occasion a two by four board. Of all the children, Scott suffered the most frequent and violent beatings. The situation grew worse the older we got; it was not long before Scott received nothing positive at all from Bud. There was so much violence in our home I dreaded coming home each day.

Pinholster’s half-sister, Tammy, likewise recalled:

Scott as a child was frequently physically abused by Scott’s step-father, Bud Brashear. Bud hit Scott with his fists as often as several times within one week. Bud’s punishments were unpredictable and severe. For instance, Bud once was awakened early, and made all of us children run in circles in the back yard until we were near collapse. I have no recollection of Bud ever praising Scott or doing anything emotionally supportive for Scott.

Pinholster’s psychiatric records also indicated that his step-father frequently used a paddle to hit him on the head, back, and shoulders, knocking him out at times without subsequent medical care. And relatives’ additional declaration testimony showed that, beginning when Pinholster was one and a half years old, his maternal grandmother “beat the hell out of’ him for resembling his biological father, whom she and her husband detested as a “good for nothing.”13 Absent this available mitigation evidence, however, the State was free to summarize Brashear’s misleading testimony as ordinary discipline, arguing in its closing statement to the jury: “She said his step-father disciplined him. So what? I am sure you have all disciplined your children. I was disciplined myself. I remember trying to run from my mother when I was 16 years old, and she couldn’t catch me any more.”

Brashear also testified that Pinholster “never really wanted for anything at home too much,” having had “everything normally materialwise that most people have,” and that although the family “didn’t have lots of money,” he always had “a roof over his head” and “decent clothes.” She even recalled his supposed embarrassment at having friends over to the house because it showed the family’s secure financial situation: “[T]he more impoverished people ... that he hung around with, he wouldn’t bring them up to the house. He said it *679was too nice a house and it ruined his image.”

As the available mitigation evidence would have shown, however, the truth was that Pinholster and his siblings suffered extreme deprivation. According to additional declaration testimony from Brash-ear’s siblings, the family “remained extremely poor” after Brashear’s second marriage, and “[t]he kids did not get enough to eat.” Once, Brashear’s sister stayed over and awoke in the middle of the night to see “the boys in the kitchen mixing flour with water, trying to make themselves something to eat.... The house was really filthy.... Completely unsupervised,” the children “ran wild and trashed wherever they were living.... They ruined apartments, furniture, everything,” until the family would “skip out on the rent and move somewhere else,” generally to another “bad neighborhood! ] with lots of crime.” All the while, “when it came to spending money, Burnice always spent it on herself first.... Although her kids looked like raga-muffins and their clothes were always old and dirty, Burnice was always dressed very nicely.” Without this evidence before the jury, however, the State was able to argue that Pinholster “came from a good home. You heard that he was not a deprived child. Had many things going for him, probably more than many children.”

iii. Family’s Criminal and Mental History

Third, with an adequate investigation, Pinholster’s trial counsel would have discovered a wealth of evidence regarding his family’s significant criminal and mental history. In her testimony, Brashear inaccurately distinguished Pinholster from the rest of his siblings, portraying him as the most wayward of her children by far. She testified that his siblings had been in “small trouble” with the law, and that they were “basically very good children”:

Q: What kind of trouble?

A: My younger son once was picked up on a drunk driving, driving under the influence, which was dropped. I guess he wasn’t really as intoxicated as they thought he was. The other was possession of some kind of drug. He got probation and was totally scared, not something you carry around in your ear.

Q: How about your daughter? A: She’s been in a little bit of trouble, yes. Mostly self-destructive to herself. She was a wild girl. She isn’t any more. She got picked up on a drunk arrest also.

When asked, “Generally speaking, was Scott like your other children?,” she answered, “No, sir.”

The available mitigation evidence would have established, however, that each of Brashear’s children had severe problems. When Pinholster’s older brother, Alvin, was twenty years old, the State charged him with the rape and sodomy of a fourteen-year-old. He later entered a state mental hospital, where doctors diagnosed him with schizophrenia and determined that he was incompetent to stand trial. After several unsuccessful attempts, Alvin ultimately committed suicide by overdosing on drugs. Pinholster’s younger brother, Terry, was diagnosed with mild depression and used drugs, and his half-sister, Tammy, first began drinking when she was eleven. At age seventeen, Tammy was charged with sexual battery and oral copulation on a fourteen-year-old girl. Tammy also had arrests for prostitution, public drunkenness, and possession of marijuana. Guy, a half-brother, who was diagnosed with manic depression and prescribed lithium, was admitted to two different psychiatric hospitals. Gary, another half-*680brother, had a history of alcoholism and a horrible temper.14

iv. Pinholster’s Substance Abuse

Fourth, had trial counsel conducted an adequate investigation, they would have discovered evidence of Pinholster’s longstanding substance abuse. At the penalty phase, Brashear testified that Pinholster grew up supported by his family, as a member of “a family that sticks close together like you would not believe,” and made no mention of his chronic drug problems. According to the additional mitigation evidence, however, the reality was that Pinholster started sniffing glue and paint and using alcohol, nicotine, and marijuana between ages ten and twelve; using secanol, or downers, between ages thirteen and fourteen; and regularly using heroin and sporadically using cocaine between ages fourteen and sixteen. This substance abuse continued into his adulthood.

v. State’s Exploitation of Brashear’s Testimony

Finally, without any of the additional mitigation evidence, the State was able to capitalize on the weakness of Brashear’s testimony in its closing argument:

What did the defendant proffer in this particular case as to ask you to come back with anything less than death? Not one person, ladies and gentleman, came into this courtroom, not one person, to tell you about anything nice this man has ever done. About anything good in his background, about anything positive that you could consider as being something, maybe there is something salvageable. Not one person except his mother. A mother clearly loves her son, ladies and gentleman. Clearly not the most unbiased witness in the world.

The State argued that the defense offered “[n]othing except a mother who loves her son. Even the most heinous person born, even Adolph Hitler probably had a mother who loved him,” and that “[i]t would probably be charitable to refer to [Pinholster] as a member of the human species.” Given the absence of a minimally adequate defense investigation, these arguments went completely unchallenged, and Pinholster’s counsel could only ask the jurors to be merciful, without providing any reason for them to do so. See Rompilla, 545 U.S. at 398, 125 S.Ct. 2456 (“This evidence adds up to a mitigation case that bears no relation to the few naked pleas for mercy actually put before the jury....”).

Based on the vast differences between Brashear’s testimony and the evidence presented at Pinholster’s habeas proceedings — as well as on the mitigating effect the additional evidence would have had on the State’s aggravation case — we conclude that it was objectively unreasonable for the California Supreme Court to determine summarily that not one of the twelve jurors would have voted against the death penalty. Wiggins, 539 U.S. at 537, 123 S.Ct. 2527. We therefore find that counsel’s deficient performance prejudiced the defense. See Strickland, 466 U.S. at 687, 104 S.Ct. 2052. We find this determination buttressed by the fact that, despite the brevity of defense counsel’s penalty phase presentation, the jury deliberated for at least two and a half days before finally returning a death verdict.

*681Even more important, we find that application of the controlling precedent in Porter, Terry Williams, Wiggins, and Rompilla — as those cases inform the meaning of Strickland, — admits of no other reasonable conclusion.

In Porter, the Court found that counsel had incompetently failed to present evidence of Porter’s abusive childhood, alcohol abuse, military service, and brain damage. Porter’s father beat his children and wife and, like Pinholster, Porter was his father’s “favorite target.” Porter, at 449. Also like Pinholster, Porter had trouble in school and attended special classes for slow learners. Id. Porter joined the military to escape his family life and was honored for fighting in two horrific battles. Id. at 454. Upon his return he developed a severe drinking problem and was diagnosed with “brain damage that could manifest in impulsive, violent behavior.” Id. at 451.

In Terry Williams, had counsel conducted an adequate investigation, they would have discovered additional mitigation evidence that “Williams’ parents had been imprisoned for the criminal neglect of Williams and his siblings,” that “Williams had been severely and repeatedly beaten by his father,” and that Williams “had been committed to the custody of the social services bureau for two years.” 529 U.S. at 395, 120 S.Ct. 1495. Williams’ counsel also would have found that he “was borderline mentally retarded and did not advance beyond sixth grade,” that he had “help[ed] to crack a prison drug ring,” and that he was a peaceful inmate. 529 U.S. at 396, 120 S.Ct. 1495 (internal quotation marks omitted). The aggravating evidence, meanwhile, was that before the murder for which Williams received the death penalty, he had been convicted of burglary, armed robbery, and grand larceny, and that after the murder, he had committed “two auto thefts and two separate violent assaults on elderly victims” and “had also been convicted of arson for setting fire in the jail while awaiting trial.” Id. at 368,120 S.Ct. 1495.

In Wiggins, the available mitigation evidence that competent counsel could have presented was that “Wiggins experienced severe privation and abuse in the first six years of his life while in the custody of his alcoholic, absentee mother,” that “[h]e suffered physical torment, sexual molestation, and repeated rape during his subsequent years in foster care,” and that he spent a period of time homeless. 539 U.S. at 535, 123 S.Ct. 2527. In addition, Wiggins had “diminished mental capacities.” Id. The only aggravating evidence, by contrast, was that he drowned his elderly victim in a bathtub and ransacked her apartment; he “d[id] not have a record of violent conduct that could have been introduced.” Id. at 514, 537, 123 S.Ct. 2527.

Finally, in Rompilla, the additional mitigation evidence was that Rompilla “was reared in [a] slum,” that his “parents were both severe alcoholics,” and that he “was abused by his father who beat him when he was young with his hands, fists, leather straps, belts and sticks.” 545 U.S. at 390-92, 125 S.Ct. 2456 (internal quotation marks omitted). This evidence also showed that Rompilla received “no expressions of parental love, affection or approval,” that he and his siblings “were not given clothes and attended school in rags,” that he drank too much alcohol, that he “suffer[ed] from organic brain damage,” and that his “IQ was in the mentally retarded range.” Id. at 392-93, 125 S.Ct. 2456 (internal quotation marks omitted). The aggravating evidence, on the other hand, was that Rompilla had prior convictions for burglary, rape, and theft, and that “the murder was committed by torture.” Id. at 378, 399, 125 S.Ct. 2456; *682Rompilla v. Horn, 355 F.3d 233, 237 (3d Cir.2004), rev’d by 545 U.S. 374, 125 S.Ct. 2456, 162 L.Ed.2d 360.

Here, the facts are remarkably similar. Like Porter, Williams, Wiggins, and Rompilla, who were all severely beaten by their parents, Pinholster suffered vicious and repeated physical abuse from both his step-father and his maternal grandmother. All five men grew up deprived in extremely poor households, lacking any meaningful parental guidance or emotional support, and four of them spent parts of their childhood in various foster homes and other institutional environments. While Pinholster, Porter, and Rompilla incurred organic brain damage as children or young adults that impaired their mental health and influenced their behavior, Williams and Wiggins had mental capacities that bordered on or amounted to mental retardation. And Pinholster, Porter, and Rompilla suffered from addictions to alcohol from an early age.

Granted, the aggravating evidence in Wiggins and Porter was not as strong as that here. Wiggins, unlike Pinholster, lacked a record of violent behavior. Porter was a decorated veteran who returned home a changed man. But the State’s aggravation case against Pinholster was not materially stronger than those in Terry Williams and Rompilla. While it is true that Pinholster boasted at trial about the many past robberies that he allegedly committed, as noted above, the available mitigation evidence of his brain damage and related mental problems could have influenced the jury’s interpretation of that testimony by suggesting an organic origin for his violent, aggressive behavior and for his penchant for exaggeration. Moreover, unlike Pinholster’s case, the aggravating evidence in Terry Williams included actual convictions for arson, burglary, armed robbery, and grand larceny; Williams’s confession to two auto thefts and to two violent assaults on elderly victims, where one of the victims “was[left] in a vegetative state and not expected to recover”; and testimony from two experts that “there was a high probability that Williams would pose a serious continuing threat to society.” 529 U.S. at 368-69, 120 S.Ct. 1495 (internal quotation marks omitted). Rompilla likewise had actual convictions of theft, burglary, and — more serious than any of Pinholster’s pre-murder crimes— rape, in which he slashed the victim with a knife. Rompilla, 545 U.S. at 378, 125 S.Ct. 2456; 355 F.3d at 237. Of even greater importance, however, unlike Pinholster’s case, the jury found that Rompilla “committed the murder by means of torture.” 355 F.3d at 236 (emphasis added).

On the other hand, the facts in Pinholster’s case are readily distinguishable from those in Van Hook, Wong v. Belmontes, and Visciotti. Nonetheless, we will discuss them in some detail here because they involved ineffective assistance of counsel and because Van Hook and Belmontes were decided while this case was pending. In Van Hook, the defendant’s attorney put vastly more effort into preparing a mitigation case than did Pinholster’s. Van Hook, 130 S.Ct. at 19. For example, Van Hook’s counsel presented eight mitigation witnesses — so many that the court found that additional “evidence from more distant relatives can reasonably be expected to be only cumulative.” Id. Here, counsel presented one witness, and that witness’s testimony was aptly described by the district court as “brief ... damaging, incomplete, and inaccurate.” Additional witnesses would not have been cumulative — indeed, they would have directly contradicted the one witness who had been put on the stand, and would have provided the only true mitigating evidence. Van Hook’s attorneys also “looked into enlisting a mitigation specialist,” id. at 18, *683presented information about Van Hook’s exposure to domestic violence, drugs, and alcohol at a young age, id. at 18, and had experts testify that his mental health problems likely “impaired his ability to refrain from the[crime]” and caused his “explosion of senseless and bizarre brutality,” id. (internal quotation marks omitted). This is precisely the type of evidence that was kept from Pinholster’s jury. Despite the Chief Judge’s best efforts to pose the dissent as a reflection of current Supreme Court jurisprudence, Van Hook has very little relevance to whether Pinholster’s attorneys made reasonable efforts to represent him during the penalty phase of trial.

The recent decision in Wong v. Belmontes is also uninstructive in this case. At the outset, the Court was careful to limit the holding by stating that “[t]he challenge confronting Belmontes’ lawyer ... was very specific.” 558 U.S. -, 130 S.Ct. 383, — L.Ed.2d-(2009). Substantial evidence (including his own boastful admission) indicated that Belmontes had committed, and escaped punishment for, a previous murder. Belmontes, 130 S.Ct. at 385. The prosecution was desperate to get that evidence in and Belmontes’s attorney “built his mitigation strategy around the overriding need to exclude it.” Id. He had to “proceed cautiously, structuring his mitigation arguments and witnesses to limit” the possibility that he would open the door. Id. at 385. Perched on this tightrope, the attorney still managed to “put on nine witnesses that he thought could advance a case for mitigation, without opening the door to the prior murder evidence.” Id. at 386. If anything, Belmontes’s attorney’s performance undermines the dissent’s argument that Pinholster’s one, ineffective mitigation witness was sufficient because his lawyers may have feared that other witnesses would have opened the door to some aggravating evidence. Diss. at 718-19. Pinholster had not committed an additional murder just waiting to be revealed, and the record reveals no other such evidence. Nor did Pinholster’s counsel assert that any such tactical reason existed for their failure to introduce the crucial mitigation evidence that they failed to uncover.

Belmontes’s lawyer showed that putting on an effective mitigation case is possible even in the face of potentially devastating aggravating evidence. The mitigating evidence presented painted a complete picture of Belmontes’s past, and the additional evidence that was not presented would have simply been cumulative: that his sister had died when he was young, that he exhibited signs of depression after her death, and that he had a strong, likeable, and respectful character. Belmontes, at 385. This evidence starkly contrasts with the unheard evidence in Pinholster’s case: organic brain damage, mental disease, childhood beatings, abandonment, and a nuclear family filled with mental illness and violence. Not only did Pinholster’s mother, the one mitigating witness, fail to paint an adequate picture, she downplayed and undermined his story in order to make herself look better on the stand.

Finally, in Visciotti, the aggravating evidence was substantially stronger, as Visciotti committed “a cold-blooded execution-style killing of one victim and attempted execution-style killing of another,” both after Visciotti and his accomplice had driven the victims to a remote area to rob them. 537 U.S. at 20, 26, 123 S.Ct. 357. Visciotti’s prior offenses, which included the “stabbing of a pregnant woman as she lay in bed trying to protect her unborn baby,” were shockingly depraved. Id. at 26, 123 S.Ct. 357. At the same time, the mitigation evidence in Visciotti was significantly weaker than that in Pinholster’s case, as Visciotti’s “troubled family background” lacked any physical abuse or privation *684comparable to that suffered by Pinholster as a child. See id. (internal quotation marks omitted).

Accordingly, we hold that the California Supreme Court’s “postcard” denial of Pinholster’s penalty phase ineffective assistance claim constituted an objectively unreasonable application of the clearly established federal law in Strickland. Pin-holster’s attorneys performed even more deficiently than the lawyers in Terry Williams, Wiggins, and Rompilla; and the balance between the available mitigating evidence and the aggravating evidence, for purposes of showing prejudice, is materially indistinguishable from that in Terry Williams and Rompilla.

We therefore affirm the district court’s grant of habeas relief on Pinholster’s penalty phase ineffective assistance claim, finding such relief warranted when properly considered under AEDPA’s deferential standards. Given the law and the facts discussed above, we are fully persuaded that it was objectively unreasonable for the California Supreme Court to determine summarily that not one of the twelve jurors would have voted against a death sentence, especially in light of the fact that the jury deliberated for almost two and a half days before finally returning a death verdict.

In doing so, we in no way minimize the brutal nature of Pinholster’s underlying crimes of conviction. As the district court acknowledged, the murders were “heinous.” Nevertheless, Terry Williams, Wiggins, and Rompilla establish that a habeas petitioner’s “excruciating life history,” Wiggins, 539 U.S. at 537, 123 S.Ct. 2527, or “nightmarish childhood,” Terry Williams, 529 U.S. at 395, 120 S.Ct. 1495, can provide mitigating evidence powerful enough to outweigh the imposition of the death penalty for even the most horrendous of crimes, and that we cannot lightly disregard a capital lawyer’s inexcusable failure to find and introduce such evidence.

Our paramount concern is not whether “few death sentences are safe from federal judges,” diss. at 685, but rather that federal judges “acknowledge[ ] the uniqueness of the punishment of death [and] ‘the corresponding ... need for reliability in the determination that death is the appropriate punishment.’ ” McCleskey v. Kemp, 481 U.S. 279, 340, 107 S.Ct. 1756, 95 L.Ed.2d 262 (1987) (Brennan, J., dissenting) (quoting Woodson v. North Carolina, 428 U.S. 280, 305, 96 S.Ct. 2978, 49 L.Ed.2d 944 (1976)). The guarantees of the United States Constitution, as interpreted by the Supreme Court, apply to our most troubled and our most upstanding citizens alike, and our duty as Article III judges to fairly and impartially apply those guarantees to all citizens compels us to rule as we do today.

IY. CONCLUSION

For the reasons explained above, we AFFIRM the district court’s decision upholding Pinholster’s conviction but granting habeas relief on his penalty phase ineffective assistance claim. The case is REMANDED for the district court to issue a writ vacating Pinholster’s death sentence, unless within a reasonable time set by the court the State conducts a new penalty phase trial or imposes a lesser sentence consistent with applicable law.

AFFIRMED and REMANDED.

. The California Supreme Court’s opinion in People v. Pinholster (Pinholster I), 1 Cal.4th 865, 4 Cal.Rptr.2d 765, 824 P.2d 571, 581-87 (1992), and our three-judge panel's majority opinion in Pinholster v. Ayers (Pinholster II), 525 F.3d 742, 749-56 (9th Cir.2008), thoroughly summarize the detailed facts in this case. With independent verification, we reiterate here only those facts material to our disposition.

. The record shows that counsel billed 1.5 hours to "[s]tart prep, for penalty phase” on April 11, 1984, 3.0 hours for "[p]rep. penalty phase and conf. with Mrs. Brashear” on April 25, 1984, and 2.0 hours for "[p]rep. penalty phase” on April 26, 1984. The dissent guesses that other records — which do not mention penalty phase preparation — might be penalty preparation in disguise (or, worse, that "perhapsfcounsel] was not diligent about time records.”). Diss. at 697. Despite our dissenting colleague’s well-known flair for "creative” writing, it is not appropriate for a federal appellate court to conjure up evidence that does not exist, especially when we have counsel’s own testimony that they did not anticipate a death penalty hearing, and thus did not prepare for it. See Pinholster II, 525 F.3d at 751.

. The dissent seems mesmerized by the fact that the California Supreme Court twice denied Pinholster’s state habeas petitions. Diss. at 684-85, 688-89, 707-09. It is true that the postcard denial, issued by the same justices who had previously denied Pinholster’s petition, was technically a second look. However, contrary to the dissent’s suggestion, the level of deference is not measured by the number of times that habeas relief has been denied. If that were the case, then the Supreme Court might have exercised greater deference in Porter, Wiggins, and Rompilla, where their respective state trial and supreme courts had both denied postconviction relief. Instead, the Court granted habeas relief anyway, because collateral habeas review is not concerned with the number of times the state did or did not grant relief. See Porter v. McCollum, 558 U.S. -, 130 S.Ct. 447, - L.Ed.2d - (2009) (per curiam); Wiggins v. Smith, 539 U.S. 510, 123 S.Ct. 2527, 156 L.Ed.2d 471 (2003); Rompilla v. Beard, 545 U.S. 374, 125 S.Ct. 2456, 162 L.Ed.2d 360 (2005).

. We need not determine in this case whether our prior decisions properly held that AEDPA deference applies to silent state court decisions such as the denial at issue here, or whether that standard of deference applies to claims involving new evidence introduced on federal habeas. See, e.g., Brown v. Smith, 551 F.3d 424, 429 (6th Cir.2008) (reviewing an ineffective assistance of counsel claim without AEDPA deference in light of new evidence introduced by a diligent petitioner). Whether we review the state court's decision de novo or for objective unreasonableness with an independent review of the record, we would grant the writ as to Pinholster’s penalty phase claim and deny the writ as to his guilt phase claims. Accordingly, we will assume for purposes of this opinion that the stricter unreasonableness standard applies.

. As previously noted, Pinholster's trial con-eluded on May 7, 1984.

. In fact, the Holland Court specifically noted, without endorsing, the practice in certain circuits of reviewing claims based on such new evidence de novo because "there is no relevant state-court determination to which one could defer.” Id. at 653, 124 S.Ct. 2736.

. The dissent suggests that Pinholster was not diligent in presenting evidence in state court because he did not present the diagnoses of specific doctors (Drs. Olson and Vinogradov) during his first habeas petition. Diss. at 689. However, Pinholster did attempt to present mental health evidence in state court and was rejected. Pinholster's request for an evidentiary hearing in state court was denied. To claim that he was not diligent because he did not present mental health evidence in state court nullifies AEDPA’s exception for diligence, and is simply illogical. The dissent also argues that Pinholster “hasn’t shown he couldn't have returned to state court” to develop the record there. Diss. at 690. Again, the genesis of this requirement is unclear. AEDPA requires only that the defendant diligently attempt to present the evidence in state court. § 2254(e)(2). Pinholster tried, but was denied that opportunity, and we know of no case law suggesting that he needed to be rejected twice.

. The dissent also uses this excuse, claiming that Pinholster was uncooperative in putting on a penalty-phase defense and claiming that he probably (and "rationally]'') preferred to die than to spend his life in prison. Diss. at 16137-38. Pinholster said no such thing, and all evidence — including the habeas petition itself — speaks to the contrary. Regardless, a difficult or fatalistic client does not give counsel license to collapse into an armchair and admit defeat. See Porter, at 454.

. Even assuming that the State had failed to provide adequate notice, counsel would not have been absolved of their duty to investigate and present mitigation evidence because the State could have relied solely on the evidence introduced at the guilt phase in seeking a death sentence, see Cal. Penal Code § 190.3. At a minimum, counsel had a duty to investigate Pinholster's background or to make a reasonable, informed decision that such an investigation was unnecessary. See Strickland, 466 U.S. at 691, 104 S.Ct. 2052; Terry Williams, 529 U.S. at 396, 120 S.Ct. 1495 ("trial counsel did not fulfill their obligation to conduct a thorough investigation of the defendant’s background”).

. Although Brainard failed to make up an excuse for his lack of preparation, the dissent *673gives him one, claiming that the attorney was employing the tactic of "falling on your sword” to help his client on habeas. Diss. at 701 n.10. This flight of fancy goes too far — the Sixth Amendment guarantee of effective counsel, see Cuyler v. Sullivan, 446 U.S. 335, 344, 100 S.Ct. 1708, 64 L.Ed.2d 333 (1980), would be rendered meaningless if every attorney who is unable to explain his ineffective assistance is assumed to be effective because he is "falling on his sword.”

. Although the State alleges that "[t]he parties had already stipulated to the admissibility of the report,” the Slate provides no record evidence to that effect, nor can we find any.

. The dissent spends some time arguing that Pinholster’s epilepsy is irrelevant because he was not suffering a fit when he committed the crimes. The point, however, is that Pinholster's brain was so damaged by his numerous head traumas that it caused epilepsy. In other words, epilepsy is an indicator of prefrontal brain damage, and pre-frontal brain damage frequently leads to aggressive, impulsive behaviors. The jury did not hear this evidence.

. The dissent minimizes this abuse, calling it "no more than spanking.” Diss. at 712. We think it safe to say that lifting a baby "up by his two hands with one hand, holding] him up in the air, and wail[ing] on him with her other hand,” "beat[ing] the hell out of him” and "while hitting him, yelling[ing] at [him] for being 'just like your father’ ” goes far, far beyond mere spanking.

. According to relatives' additional declaration testimony, Pinholster's biological father also "did nothing but drink and party,” had fits of anger and mood swings, and "sometimes would stay up all night pacing the house, yelling and screaming.” After undergoing a mental-health evaluation for a custody hearing, he received a diagnosis as paranoid with narcissistic personality disorder.