Full opinion text
PHILLIPS, Circuit Judge. This appeal arises out of the murders of Jerald Thurman and Mary Bowles in Tulsa, Oklahoma. At trial, a jury convicted defendant John Hanson for the murder of Mary Bowles with malice aforethought and for the felony murder of Thurman. At the penalty phase, the jury found three aggravating circumstances related to Bowles’s murder. Upon the jury’s verdict, the trial court sentenced Hanson to death. See Okla. St. tit. 22, § 1007 (2015). On direct appeal, the Oklahoma Court of Criminal Appeals (“OCCA”) reversed Hanson’s death sentence and remanded for a new sentencing hearing. Hanson v. State (Hanson I), 72 P.3d 40, 55 (Okla.Crim.App.2003). At the resentencing hearing, the jury again sentenced Hanson to death for Bowles’s murder. Hanson appealed his sentence to the OCCA, which struck the jury’s finding of the great-risk-of-death aggravator but still affirmed his sentence. Hanson v. State (Hanson II), 206 P.3d 1020, 1033, 1036 (Okla.Crim.App.2009). After the OCCA denied Hanson’s application for collateral relief, Hanson filed a petition for a writ of habeas corpus under 28 U.S.C. § 2254. The district court denied the petition, but it granted him a certificate of appealability (“COA”) to pursue several arguments before this court. We also granted a COA on all of his remaining issues. Before us, Hanson argues five general issues. He asserts six instances of ineffective assistance of both trial and appellate counsel and two instances of prosecutorial misconduct. He also argues that we should invalidate his death sentence because the OCCA invalidated the great-risk-of-death aggravator. He also claims there was an error in the jury instruction on mitigating evidence that impermissibly limited the jurors’ consideration of mitigation evidence. Finally, he raises cumulative error. Exercising jurisdiction under 28 U.S.C. §§ 1291 and 2253(a), we conclude that none of Hanson’s arguments merit relief. Accordingly, we affirm the district court’s denial of the habeas petition. I. BACKGROUND AND PROCEDURAL HISTORY The following set of facts detail John Hanson’s and Victor Miller’s murderous exploits and later crime spree before their eventual arrests. It begins and ends with Mary Bowles, an older woman and volunteer at Saint Francis’s hospital, who frequently walked around the Promenade Mall for exercise. On August 31, 1999, Hanson and Miller carjacked Bowles’s car, with her in it, from outside the Mall in Tulsa, Oklahoma. Hanson II, 206 P.3d at 1025. Hanson, as usual, carried his 9 millimeter semiautomatic pistol, and Miller carried his .38 revolver. Id. Miller drove the car, with Hanson and Bowles in the backseat, to an isolated area near a dirt pit that Jerald Thurman owned. Id. Thurman was at the pit loading a dump truck with dirt for delivery. Id. He was talking to his nephew, James Moseby, on his cell phone when he saw Bowles’s car circling in the pit. Id. After Thurman and Moseby ended their call, Miller shot Thurman four times with his .38 revolver, including one shot to the head. Id. Throughout this time, Bowles remained in the car. Id. Moseby arrived at the dirt pit about ten minutes after the phone conversation, where he found Thurman lying on the ground, unconscious, with multiple gunshot wounds. Thurman died from his wounds two weeks later. Id. Meanwhile, Miller drove the car a short distance away from the pit, heading south on what is commonly known as Peanut Road and told Hanson, “You know what you have to do.” Hanson v. Sherrod (Hanson III), No. 10-CV-0113-CVE-TLW, 2013 WL 3307111, at *8 (N.D.Okla. July 1, 2013) (unpublished). On Peanut Road, Hanson removed Bowles from the car and shot her multiple times with his 9 millimeter semiautomatic pistol. Hanson II, 206 P.3d at 1025. Her significantly decomposed body was discovered on September 7, with a bullet in the right side of her chest. The state’s forensic pathologist testified that Bowles suffered “without a doubt four and, likely, six” gunshot wounds. The police found two spent cartridges at the scene of Bowles’s murder, one .38 special and one 9 millimeter. After Hanson killed Bowles, Miller and Hanson drove the car a few miles down the road and registered at the Oasis Motel. Hanson II, 206 P.3d at 1025. Miller called his wife and asked her to bring him a rag. She complied, and he used the rag to wipe down the inside of the car. Miller and Hanson then abandoned the car at the motel. Id. This was not the end of Hanson’s and Miller’s criminal pursuits. On September 3, Hanson and Miller robbed Dreamland Video Store at gunpoint. Hanson III, 2013 WL 3307111, at *1 (citing Hanson II, 206 P.3d at 1025). They entered the store and looked around for a few minutes. Hanson pulled his gun, a 9 millimeter semiautomatic, on one of the store’s patrons. He forced the patron to enter a side room and lay face down on the ground. Hanson placed his gun against the patron’s back, moved it up to his head, and finally tied the patron’s wrists and ankles with duct tape. Next, Hanson removed the patron’s wallet from his pants and placed the barrel of the gun against his neck. Hanson then left the room, shutting the patron inside. Soon afterward, Hanson and Miller fled from the store. On September 8, a few days later, Hanson and Miller robbed the Tulsa Federal Employees Credit Union at gunpoint. Hanson again carried his 9 millimeter pistol, and Miller carried his .38 revolver. The two men entered the bank and got in line for the bank teller. Stepping up to the counter, Hanson passed the bank teller a note, which read: “Do not panic. Don’t hit any buttons. If you do, you will be the first killed. And then the rest will follow in bloodshed. Put all the money in a brown envelope — [manila] envelope.” Tr. Trans. II, Vol. VIII at 1618. He also pointed to his weapon so she would know that he was armed. Hanson passed her the envelope, and she filled it with money, including a dollar bill that alerts the FBI and a dye pack. After she handed the envelope back, Hanson and Miller fled the bank. Finally the next day, law enforcement put an end to Hanson and Miller’s armed-felony binge. Miller’s wife, Phyllis, had been the driver for their robbery of the credit union. After the robbery, Miller and Phyllis got into an argument, and Miller “tore up” the car. Tr. Trans. I, Vol. IX at 1569. Miller and Hanson then retreated to the Muskogee Econo Lodge, and Phyllis called a “wrecker” to take her back to where she was staying at a Motel 6. Id. at 1570. When she arrived, she went to a pay phone and called Crime Stoppers to tell them that she knew who had committed the bank robbery. At trial, she testified that she did so because she “didn’t want to get in trouble.” Id. at 1571. The next morning, fearing for her safety, she called Crime Stoppers again to see if they had arrested the men. She explained at trial that, the day before their argument, Miller had pulled a gun on her. She also called because she had more information — she had seen Bowles’s car at the Oasis Motel. All told, she told the police where they could locate Hanson and Miller. Soon after receiving Miller’s information, one team of officers went to Bowles’s car and lifted Hanson’s fingerprint from the driver’s side seatbelt, and Miller’s fingerprint from the front passenger seatbelt. Another team of officers arrived at the motel to arrest Hanson and Miller. At 6:00 a.m., the “entry team” of police officers went up to the Lodge and “staged up.” Tr. Trans. I, Vol. VIII at 1835, 1345. After evacuating all motel rooms except for two, a hostage negotiator called to tell the officers that they had “made contact” with Room 135 and 141 and had demanded that the occupants come out. Id. at 1336. In response, an older black male walked out of Room 141. The police took him into custody. About 15 minutes later, Miller came out of Room 135, and the police took him into custody. In contrast, an uncooperative Hanson barricaded himself in Room 135, refusing to communicate or come out. Throughout the day, an FBI negotiator made four or five approaches to the room, trying to make contact. The police officers would approach the door and “stage outside” Room 135, and the FBI negotiator would yell into the room trying to make contact. Id. at 1338. Hanson did not respond to any of these entreaties or the officers’ numerous telephone calls. Eventually, the police shut off the water and phone lines to the room. One officer set up surveillance in an adjoining room, Room 137. He heard what sounded like the porcelain lid coming off the toilet and something being dropped inside its tank. At 1:30 p.m., the police finally entered Hanson’s room. One officer broke open the door, while another deployed a temporarily debilitating chemical gas agent, CS gas, into the room. After ten or 15 seconds, the gas forced Hanson out of the room. After taking Hanson into custody, and having already obtained a search warrant, both FBI and state police officers searched Hanson and Miller’s room. Inside the toilet tank, the officers found two guns — a .38 caliber revolver and a 9 millimeter semiautomatic pistol. These were the same guns used in the murders of Thurman and Bowles. And they were the same guns used in the robbery of the video store. In the toilet tank, they also found a bag full of live ammunition for the .38 revolver and duct tape. The 9 millimeter pistol was loadéd with seven live rounds. The government jointly charged Hanson and Miller with the first-degree murder of Bowles (Count One) and the first-degree murder of Thurman (Count Two). Alternatively, it charged the counts as felony murders. At Miller’s request, the trial court severed Hanson and Miller’s trials. At trial, attorneys Jack Gordon and Eric Stall represented Hanson. Rashad Barnes, a former coworker of Hanson’s, provided crucial testimony against Hanson in the government’s case. Barnes and Hanson had worked together, along with Hanson’s cousin Tremaine Wright, at Blue Bell Creameries, where they loaded and unloaded pallets of ice cream. Between February and April 1999, the three men drove together to and from work. According to Barnes, sometime in late August or early September 1999, he was sitting alone in his backyard. During this general time, Barnes let Hanson live in Barnes’s car, which was parked in Barnes’s backyard. One day near then, at about 3:00 p.m., Hanson showed up in Barnes’s backyard acting “real nervous, real jittery.” Tr. Trans. I, Vol. VII at 1157, 1159. Barnes had not seen Hanson for about a week. Barnes described Hanson as “seared” and “terrified,” and he recollected that Hanson “kept saying everything went bad.” Id. at 1160, 1164. Barnes testified that Hanson told him that he and Miller had carjacked a car from the Promenade Mall with an old lady in it. According to Barnes, Hanson said that he and Miller put the old lady in the backseat, Hanson got in the backseat with her, and Miller drove them to a back road where they had planned to let her out. Hanson told Barnes that he and Miller had carjacked the car “[t]o do robberies.” Id. at 1161. Continuing with his account, Hanson told Barnes that a man in a dump truck saw them, so Miller got out of the car and shot the man. Judging from Hanson’s hand motions, Barnes understood that Miller shot the man in the head and chest. Hanson also told Barnes that the man’s body was “smoking.” Id. at 1162. As he reloaded his gun, Miller had gotten back into the car and told Hanson, “You know what you have to do.” Id. Hanson told Barnes that on the ride back to the road the old lady asked him, “do you have any kids or anyone who [loves you]?” Id. at 1163. Hanson told Barnes that he had told her to shut up and then he punched her. Not far from the dirt pit, Miller stopped the car, and Hanson shot the old lady and concealed her in the bushes. Near the end of the conversation, Hanson said to Barnes, “I hope that none of you all get caught up in this.” Id. at 1167. Then he walked away. Barnes did not see him again until trial. The jury convicted Hanson of first-degree murder of Bowles for Count One, and felony murder of Thurman for Count Two. At sentencing, the jury found three aggravating circumstances under Oklahoma law: (1) that Hanson had a prior conviction for a violent felony; (2) that he knowingly created a great risk of death to more than one person; and (3) that he posed a continuing threat to society. The jury fixed his punishment as death for Count One, and as life imprisonment for Count Two. On May 23, 2001, the court sentenced him to death. The OCCA affirmed Hanson’s murder convictions on appeal, but due to errors at the penalty phase it reversed his death sentence for Count One and remanded for resentencing. Hanson I, 72 P.3d at 45. Just a few days before his resentencing hearing was to begin, Hanson learned of new, possibly exculpatory evidence. A fellow inmate of Miller’s attested that Miller had confessed to shooting Bowles. Hanson filed an application for post-conviction relief based on the new evidence. The state district- court granted his request for a new trial based on the newly discovered evidence. But the OCCA granted the government’s Petition for Writ of Prohibition and reversed the district court’s decision, concluding that the district court did not have jurisdiction over Hanson’s application. It vacated the new-trial order as void and remanded the case for resentenc-ing. In January 2006, Hanson’s resentencing hearing was finally held. He again was represented by Gordon. By this time, Barnes had been killed in an unrelated incident. Hanson III, 2013 WL 3307111, at *8. Thus, the prosecution read Barnes’s trial testimony into the record, over Hanson’s objections. It also called other witnesses who had testified at the first sentencing hearing. In addition to Hanson’s familial witnesses, the defense team called Dr. Jeanne Russell, Ed.D., a licensed psychologist. She had performed a social history and risk assessment on Hanson, and she testified about her findings. A risk assessment is intended to uncover what sort of risk or threat a person may present in a prison setting to other inmates and guards. In this case, it was done in response to the government’s allegation of the aggravating circumstance that Hanson was dangerous or a continuing threat to society. Dr. Russell testified that she considered him to be a low risk to society. At the end of the resentencing hearing, the jury recommended a death sentence for Hanson after finding three aggravating circumstances: (1) Hanson had an earlier felony involving the use or threat of violence; (2) he had knowingly created a great risk of death to more than one person; and (3) he had committed the murder to avoid or prevent a lawful arrest or prosecution. Based upon the jury’s recommendation, the court sentenced Hanson to death for Count One, Bowles’s murder. Hanson appealed, and the OCCA invalidated the aggravating circumstance that he had knowingly created a great risk of death to more than one person. Hanson II, 206 P.3d at 1033-34. After reweighing the remaining aggravating circumstances against the mitigating ones, it affirmed Hanson’s death sentence. Id. at 1036. The United States Supreme Court denied certiorari. Hanson v. Oklahoma, 558 U.S. 1081, 130 S.Ct. 808, 175 L.Ed.2d 568 (2009). In 2008, Hanson filed an application for post-conviction relief, which the OCCA denied. After this, Hanson filed a successive application, which was also denied. Then on December 6, 2010, Hanson filed his federal habeas petition with the United States District Court for the Northern District of Oklahoma, raising nine grounds for relief. Hanson III, 2013 WL 3307111, at *5. The district court considered his petition and denied relief on all grounds. Id. at *40. But it granted Hanson a COA to appeal its decision on some of his claims: 1. Trial counsel provided ineffective assistance by failing to call Ahmod Henry as a witness; 2. Trial counsel provided ineffective assistance by failing to raise all available objections to Barnes’s testimony; 3. Trial counsel provided ineffective assistance by failing to object to prose-cutorial misconduct; 4. Trial counsel provided ineffective assistance by failing to call available mitigating witnesses; 5. Appellate counsel provided ineffective assistance by failing to argue that trial counsel was ineffective for failing to bring forward mitigation evidence of Hanson’s mental illness and brain damage; and 6. Appellate counsel provided ineffective assistance by failing to argue that trial counsel was ineffective for failing to challenge the government’s failure to specify the predicate crime supporting the avoid-arrest aggravator. See id. Hanson now appeals, raising the six issues for which the district court granted a COA, as well as an additional three issues that the district court denied: 1. We should invalidate his death sentence because the OCCA invalidated the great-risk-of-death aggravator; 2. The jury instruction on mitigating evidence prevented the jurors from considering and giving effect to all of the mitigating evidence they heard; and 8. The cumulative effect of errors at both stages of trial deprived Hanson of his constitutional rights under the Eighth and Fourteenth Amendments. We granted COAs on these three additional issues. Consequently, we have jurisdiction to hear all nine claims. II. DISCUSSION This court’s review of habeas petitions is governed by the Antiterrorism and Effective Death Penalty Act of 1996 (“AEDPA”). Under AEDPA, when a state court has considered a claim on the merits, this court may grant a habeas petition only if the decision “was contrary to, or involved an unreasonable application of, clearly established Federal law, as determined by the Supreme Court of the United States” or “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)(1), (2) (2015). The AEDPA standard is “highly deferential” and requires that we give “state-court decisions ... the benefit of the doubt.” Littlejohn v. Trammell, 704 F.3d 817, 824 (10th Cir.2013) (quoting Woodford v. Visciotti, 537 U.S. 19, 24, 123 S.Ct. 357, 154 L.Ed.2d 279 (2002) (per curiam)). To analyze a § 2254 claim, we first determine whether the petitioner’s claim is based on clearly established federal law, focusing exclusively on Supreme Court decisions. Hooks v. Workman, 689 F.3d 1148, 1163 (10th Cir.2012); Bland v. Sirmons, 459 F.3d 999, 1009 (10th Cir.2006). If so, then we consider whether the state court’s decision was “contrary to”'or “an unreasonable application of’ that law. Bland, 459 F.3d at 1009. If clearly established law exists, a state court decision is “contrary to” it only if “the state court applies a rule that contradicts the governing law set forth in [Supreme Court] cases or if the state court confronts a set of facts that are materially indistinguishable from a decision of [the Supreme Court] and nonetheless arrives at a [different] result.” Id. (first and second alterations in original) (quoting Williams v. Taylor, 529 U.S. 362, 405-06, 120 S.Ct. 1495; 146 L.Ed.2d 389 (2000)). A state court decision unreasonably applies federal law if “the state court identifies the correct governing legal principle from [Supreme Court] decisions but unreasonably applies that principle to the facts of the prisoner’s case.” Id. (alterations in original) (quoting Williams, 529 U.S. at 413, 120 S.Ct. 1495). “A state court’s determination that a claim lacks merit precludes federal habeas relief so long as ‘fairminded jurists could disagree’ on the correctness of the state court’s decision.” Harrington v. Richter, 562 U.S. 86, 101, 131 S.Ct. 770, 178 L.Ed.2d 624 (2011) (quoting Yarborough v. Alvarado, 541 U.S. 652, 664, 124 S.Ct. 2140, 158 L.Ed.2d 938 (2004)). “[Evaluating whether a rule application was unreasonable requires considering the rule’s specificity.” Id. (alterations in original). The more general the rule, the more leeway we give to the state courts in reaching decisions on a case-by-case basis. Id. When we review a state court’s decision, “we are precluded from issuing the writ simply because we conclude in our independent judgment that the state court applied the law erroneously or incorrectly. Rather, we must be convinced that the application was also objectively unreasonable.” McLuckie v. Abbott, 337 F.3d 1193, 1197 (10th Cir.2003) (citing Williams, 529 U.S. at 412, 120 S.Ct. 1495). AEDPA mandates that state court fact findings are presumptively correct and may be rebutted only by “clear and convincing evidence.” 28 U.S.C. § 2254(e)(1); accord Welch v. Workman, 639 F.3d 980, 991 (10th Cir.2011). We review the federal district court’s conclusions of law de novo and its factual determinations for clear error. Hooks, 689 F.3d at 1163 (quoting McCracken v. Gibson, 268 F.3d 970, 975 (10th Cir.2001)). When a state court has not considered a claim on the merits, we are “not constrained by the deference principles in § 2254(d).” Cargle v. Mullin, 317 F.3d 1196, 1212 (10th Cir.2003). A. Ineffective Assistance of Counsel Claims Hanson argues that his Sixth and Fourteenth Amendment rights were violated by ineffective assistance of counsel at trial and on appeal. He contends that his trial counsel was ineffective for failing to: (1) call Ahmod Henry as a witness in his casein-chief; (2) raise additional grounds for objecting to the introduction of Barnes’s earlier trial testimony; (3) investigate and introduce mitigating evidence at sentencing; and (4) object to prosecutorial misconduct. He asserts that his appellate counsel was ineffective for failing to challenge his trial counsel’s ineffectiveness in neglecting to put forth evidence of mental illness and brain damage. Last, he argues that both his trial and appellate counsel were ineffective for failing to argue that the aggravating circumstance for avoiding arrest or prosecution should have been invalidated based on the government’s failure to allege a specific crime Hanson sought to avoid by murdering Bowles. i. Standard of review for ineffective assistance of counsel claims It is undisputed that federal law clearly establishes the right to effective assistance of counsel. See Strickland v. Washington, 466 U.S. 668, 684, 686, 104 S.Ct. 2052, 80 L.Ed.2d 674 (1984) (recognizing that “the Sixth Amendment right to counsel exists, and is needed, in order to protect the fundamental right to a fair trial” and that the “right to counsel is the right to effective assistance of counsel” (citation and internal quotations omitted)). “The benchmark for judging any claim of ineffectiveness must be whether counsel’s conduct so undermined the proper functioning of the adversarial process that the trial cannot be relied on as having produced a just result.” Id. at 686, 104 S.Ct. 2052. To prevail on a claim of ineffective assistance of counsel, Hanson must show both that his counsel provided deficient assistance and that the deficiencies prejudiced his defense. Id. at 687, 104 S.Ct. 2052. First, to show that his counsel was deficient, Hanson must demonstrate that the errors were so serious that “counsel was not functioning as the ‘counsel’ guaranteed the defendant by the Sixth Amendment.” Id.; see also Wilson v. Sirmons, 536 F.3d 1064, 1083 (10th Cir.2008) (“Counsel’s performance must be ‘completely unreasonable’ to be constitutionally ineffective, not ‘merely wrong.’ ” (quoting Hoxsie v. Kerby, 108 F.3d 1239, 1246 (10th Cir.1997))). “Judicial scrutiny of counsel’s performance must be highly deferential.” Strickland, 466 U.S. at 689, 104 S.Ct. 2052; see also Hooks, 689 F.3d at 1186 (“[0]ur review of counsel’s performance under the first prong of Strickland is a ‘highly deferential’ one.” (alteration in original)). Furthermore, we strongly presume that “an attorney acted in an objectively reasonable manner and that an attorney’s challenged conduct might have been part of a sound trial strategy.” Bullock v. Carver, 297 F.3d 1036, 1046 (10th Cir.2002) (emphasis in original); see also Byrd v. Workman, 645 F.3d 1159, 1168 (10th Cir.2011). We must “judge the reasonableness of counsel’s challenged conduct” on the specific facts of the case “viewed as of the time of counsel’s conduct.” Strickland, 466 U.S. at 690, 104 S.Ct. 2052; accord United States v. Challoner, 583 F.3d 745, 749 (10th Cir.2009). We afford great deference to trial counsel’s strategy but do not allow it to obviate the requirement that counsel perform adequately. See, e.g., Williams, 529 U.S. at 396-98, 120 S.Ct. 1495 (holding that trial counsel performed so inadequately as to prejudice the defendant). “The pivotal question is whether the state court’s application of the Strickland standard was unreasonable. This is different from asking whether defense counsel’s performance fell below Strickland’s standard.” Harrington, • 562 U.S. at 101, 131 S.Ct. 770. Where we are applying both the Strickland standard and § 2254(d), our review is “doubly” deferential. Id. at 105, 131 S.Ct. 770 (citations omitted); see also Knowles v. Mirzayance, 556 U.S. 111, 123, 129 S.Ct. 1411, 173 L.Ed.2d 251 (2009) (“[B]ecause the Strickland standard is a general standard, a state court has even more latitude to reasonably determine that a defendant has not satisfied that standard.”). Second, to show that the outcome of his trial was prejudiced by counsel’s error, the defendant must show that those “errors were so serious as to deprive the defendant of a fair trial, a trial whose result is reliable.” Strickland, 466 U.S. at 687, 104 S.Ct. 2052. To establish prejudice, he must demonstrate “there is a reasonable probability that, absent the errors, the factfinder would have had a reasonable doubt respecting guilt.” Id. at 695, 104 S.Ct. 2052; see also Hooks, 689 F.3d at 1187. A reasonable probability “is a probability sufficient to undermine confidence in the outcome.” Strickland, 466 U.S. at 694,104 S.Ct. 2052. If confidence in either the conviction or the sentence is undermined, prejudice has been established and relief should be granted. Id. at 694-95, 104 S.Ct. 2052 (rejecting a preponderance of the evidence standard as too stringent); accord Byrd, 645 F.3d at 1168. Hanson raises six claims of ineffective assistance of counsel. We address each of these arguments in turn. ii. Failure to interview and call a witness Hanson contends that his trial counsel, Gordon, performed deficiently by failing to call Ahmod Henry in the defense’s case-in-chief at the resentencing hearing when Gordon knew that Henry had potentially exculpatory information. Mere days before the resentencing hearing was to occur in 2005, Gordon had learned that back in 2003 Henry had told Detective Michael Nance about a conversation between him and Miller while incarcerated together, in which Miller allegedly confessed to killing Bowles. In this interview, Detective Nance, after establishing that Henry and Miller were in segregation together, asked Henry: Q: [O.K.] And did you have any conversations with [Miller]? A: Yeah. Yes. Q: O.K. What did your conversations consist of? A: Shit, we was just talking about things that happened in the lifetime, and he started telling me something about some robberies, how he was making money out there, saying he did a lot of robberies, and he ... him and his friend was at a motel, and they got busted, and he said he was running around killing people doing the robbery. He said he killed a bitch. That’s all he said, “I killed ... I killed a bitch.” Q: O.K. Did he ... was he anymore [sic] specific about who he killed or ... or ... how he killed her or ... or anything like that? A: He (inaudible) shot her. Q: You say he shot her? A: He killed a bitch. Q: O.K. Did he ... did he tell you how he shot her or ... A: He didn’t say. He just said he killed the bitch. Q: O.K. Did he tell you who he was with? You said he was with a friend. A: Yeah, he was with a friend. He never said his friend[’s] name. Whoever the friend was is the one that got caught at the motel with him. Q: O.K. And is there anymore [sic] information that you know about this that ... that I haven’t asked you? A: No, sir. O.R. Yol. VII at 1258. At Hanson’s resentencing hearing, Gordon chose not to call Henry as a witness. Instead, he managed in effect to introduce Henry’s testimony through his cross-examination of the government’s witness, Detective Nance. Detective Nance acknowledged that Henry had told him Miller had confessed to “killing] a bitch.” Tr. Trans. II, Vol. VII at 1493. But he quickly disparaged Henry’s credibility, characterizing him as a “liar” and as someone who had previously provided unreliable information to the police during his frequent calls to them. Hanson argues that Gordon’s failure to put Henry on the stand and present him in a credible manner, or even to interview him before the hearing, was “certainly unreasonable and not [a decision] based on strategy.” Appellant’s Br. at 21. The OCCA resolved the issue on deficiency grounds, concluding that counsel had a sound strategy in introducing Henry’s testimony through Detective Nance. Hanson II, 206 P.3d at 1032. This strategy allowed counsel to present Miller’s confession to the jury without the possibility for Henry to be cross-examined. Id. The OCCA stated that “[a]rguably this was the best of all possibilities for Hanson since Henry had credibility problems and was known for being unreliable. Defense counsel made a sound strategy decision not to call Henry....” Id. We cannot say that the OCCA improperly applied Strickland in determining that Gordon operated under sound strategy. The district court agreed with the OCCA. Hanson III, 2013 WL 3307111, at *30-31. We begin with the presumption that Gordon had a sound trial strategy when he decided not to call Henry as a witness. See Strickland, 466 U.S. at 689, 104 S.Ct.. 2052. Gordon himself reinforced this presumption. Outside the presence of the jury, in support of his right to question Detective Nance about the conversation, Gordon explained to the presiding judge that he did not want to question Henry directly because “I don’t know whether Ahmod Henry [will invoke his Fifth Amendment right] — there’s no telling what he’ll do. He’s a long-time crook and known for getting funny notions.” Tr. Trans. II, Vol. VII at 1468. Gordon’s comment demonstrates his own concern regarding Henry’s credibility and provides a reasonable explanation for why he did not call Henry as a witness. We deem this to be sound trial strategy under Strickland’s deferential standard. See, e.g., Harrington, 562 U.S. at 108-09, 131 S.Ct. 770 (concluding that an attorney’s decision not to pursue expert blood testimony was a sound strategy under deferential Strickland standard because such testimony could have had negative consequences for the defense); United States v. Orozco, 301 Fed.Appx. 783, 785 (10th Cir.2008) (unpublished) (concluding that an attorney was not deficient for failing to call potentially exculpating witness because his credibility could taint the exculpating evidence introduced on direct examination). Depending on what Henry told him, it is possible that Gordon might have provided better counsel had he thoroughly interviewed Henry before deciding against eliciting the testimony directly from him. But this is far from certain, and even had it worked out that way, Gordon’s failure to do so hardly meets Strickland’s deficiency standard. “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.” Strickland, 466 U.S. at 689, 104 S.Ct. 2052; accord Romano v. Gibson, 278 F.3d 1145, 1154 (10th Cir.2002). When we consider Gordon’s perspective at the time of his decision, we believe it made sense for him to decide not to call Henry on direct examination for fear of what Henry might say. Because we hold that Gordon was not deficient by failing to call Henry in his case-in-chief, we do not consider prejudice. Thus, we affirm the district court’s holding on this issue. iii. Failure to raise all available grounds for impeachment of witness’s testimony Hanson next asserts that Gordon provided ineffective counsel by failing to object to the introduction of Barnes’s trial testimony at the resentencing hearing based on Miller’s testimony at his own trial. Because Barnes was deceased by the time of the resentencing hearing, the transcript of his trial testimony was read into the record. Gordon argued vigorously that the newly discovered evidence — Henry’s statement — should prevent the admission of Barnes’s testimony, but he did not mention Miller’s trial testimony specifically as a separate ground for objection. In fact, Gordon had never read the transcript from Miller’s trial. Because Barnes’s testimony was the only direct evidence identifying Hanson as Bowles’s shooter, Hanson argues that his counsel was ineffective for failing to raise every possible objection to the testimony. Thus, the question is whether Gordon’s failure to read Miller’s trial transcript was such serious error as to render his performance completely unreasonable. See Wilson, 536 F.3d at 1083. And if so, whether that deficiency prejudiced the outcome of Hanson’s trial. See id. The OCCA concluded that Gordon had not been deficient because his decision not to present evidence from Miller’s trial testimony “appears reasonable and strategic.” Hanson II, 206 P.3d at 1032. It found that there were “sound reasons to shield Hanson’s jury from evidence of Miller’s trial testimony,” including: (1). “that Miller’s testimony inculpated Hanson”; and (2) “that Miller’s testimony exculpating himself and implicating Barnes was refuted by objective facts.” Id. at 1027. Among the objective facts were these: (1) Hanson and Miller’s fingerprints, not Barnes’s, were found in Bowles’s car; and (2) Hanson and Miller robbed the liquor store, the video store, and the credit union, and they were arrested in Muskogee with the firearms used to kill Thurman and Bowles. Id. at 1027 n. 12. The district court agreed. Hanson III, 2013 WL 3307111, at *32. It is well established that “counsel has a duty to make reasonable investigations or to make a reasonable decision that makes particular investigations unnecessary.” Strickland, 466 U.S. at 691, 104 S.Ct. 2052. First, we tackle the question of whether Gordon’s failure to read Miller’s trial transcript was error. Gordon admits that he never read Miller’s trial transcript, which means he was unaware of any potential benefits the transcript might provide. But we have trouble accepting Hanson’s proposition that this omission constitutes deficient performance. The Supreme Court has recognized that “when counsel focuses on some issues to the exclusion of others, there is a strong presumption that he did so for tactical reasons rather than through sheer neglect.” Yarborough v. Gentry, 540 U.S. 1, 8, 124 S.Ct. 1, 157 L.Ed.2d 1 (2003) (per curiam) (citing Strickland, 466 U.S. at 690, 104 S.Ct. 2052). Gordon already had grounds for objecting to the introduction of Barnes’s testimony: Henry’s exculpatory statement to Detective Nance regarding Miller’s confession. The “Sixth Amendment guarantees reasonable competence, not perfect advocacy judged with the benefit of hindsight.” Id. (citing Bell v. Cone, 535 U.S. 685, 702, 122 S.Ct. 1843, 152 L.Ed.2d 914 (2002)). Thus, we do not think this omission satisfies Strickland’s notion of deficient performance. Yet even if we were to reach prejudice, Hanson’s argument would still fail. He emphasizes that Miller’s trial contained evidence that Barnes was friends with Miller. For instance, Miller testified that he had been to Barnes’s house several times, that the weapons used in the robbery belonged to Barnes and were kept in his house, and even that Barnes participated in the homicides. Miller v. State, 98 P.3d 738, 742 & n. 11 (Okla.Crim.App.2004). But these potentially useful scraps of evidence are undermined and countered by other disadvantageous components of Miller’s testimony, such as the inconvenient truth that Hanson and Miller were later caught committing other crimes with the same firearms used in the murders of Thurman and Bowles. As such, Hanson is unable to demonstrate that there is a “probability sufficient to undermine confidence in the outcome” of his trial. Strickland, 466 U.S. at 694, 104 S.Ct. 2052. We hold that even if counsel erred by not reading Miller’s trial transcript, such error did not prejudice the outcome of Hanson’s case because Barnes’s trial testimony would have been admitted regardless. We affirm the district court’s ruling on this issue. iv. Failure to investigate and present mitigating evidence Hanson next argues that his trial counsel was ineffective because he failed to investigate and present available mitigating witnesses, thereby failing to create a compelling and complete story for the jury. Gordon called one expert witness to rebut the continuing-threat aggravator. He also called four lay witnesses on Hanson’s behalf: his ten-year-old son Marq-uelle, his ex-girlfriend, his ex-girlfriend’s brother, and his ex-girlfriend’s niece. As part of his application for post-conviction relief, Hanson submitted to the OCCA the affidavits of 13 additional mitigating witnesses, who claim that they would have testified at his resentencing hearing if asked. A few of the witnesses even expressed indignation at not being given the opportunity to testify. Hanson contends these witnesses would have painted a fuller picture for the jury. After reviewing the new affidavits, the OCCA rejected this claim. Hanson II, 206 P.3d at 1032. It concluded that the new character evidence was substantially similar to the testimony already provided at the re-sentencing trial, and so it was not “persuaded that presenting additional character evidence of the same type would have changed the outcome of the trial.” Id. After conducting its own review, the district court agreed, explaining that “[t]his is not a case where trial counsel did not investigate or present appropriate mitigating evidence.” Hanson III, 2013 WL 3307111, at *34. Moreover, it found the additional evidence “somewhat duplicative, and of marginal value.” Id. at *36. In the case of mitigating evidence, the Sixth Amendment imposes a duty on counsel “to make reasonable investigations or to make a reasonable decision that makes particular investigations unnecessary.” Strickland, 466 U.S. at 691, 104 S.Ct. 2052. Even under AEDPA’s deferential standard, “we are ... conscious of the overwhelming importance of the role mitigation evidence plays in the just imposition of the death penalty.” Mayes v. Gibson, 210 F.3d 1284, 1288 (10th Cir.2000). Because of the enormous stakes confronted in a capital case, this court has stated that we must ensure that “the sentencing jury makes an individualized decision while equipped with the ‘fullest information possible concerning the defendant’s life and characteristics,’ and must scrutinize carefully any decision by counsel which deprives a capital defendant of all mitigation evidence.” Id. (quoting Lockett v. Ohio, 438 U.S. 586, 603, 98 S.Ct. 2954, 57 L.Ed.2d 973 (1978)). Even amidst this backdrop, we do not think that Gordon committed error by failing to present the additional mitigating witnesses because the content was duplicative. We begin by reviewing the mitigating evidence that Gordon actually presented at the resentencing hearing. He called four mitigating witnesses who provided testimony to the effect that Hanson was a kind, loving, and hard-working person, and a good father: • Tenika Simmons, Hanson’s ex-girlfriend’s niece, testified that Hanson helped her to get through some dark times in her life and talked her out of committing suicide. She described Hanson as a “good father,” Tr. Trans. II, Vol. X at 1781, and as a nonviolent person. • Eric Knowles, Hanson’s ex-girlfriend’s brother and a coworker of Hanson’s for some time, testified that Hanson was a “good worker” who “worked his butt off.” Id. at 1787. He said Hanson was neither violent nor aggressive. He shed light on how difficult the death of Hanson’s father was on him, explaining that his father’s death “really shook his world up.” Id. at 1790. He characterized him as “a follower” who required direction and structure. Id. at 1791. • Ledocia Warrior, Hanson’s ex-girlfriend of four years, testified that Hanson was a “very caring and loving person ... [who] never showed any signs of anger.” Id. at 1803. She described their son Marquelle as the most important person in Hanson’s life and explained that Hanson and Marq-uelle have “a very loving communication.” Id. at 1808. • Marquelle Hanson, Hanson’s son, testified that he has a “pretty good relationship” with his father and that he looks forward to his father’s letters from prison. Id. at 1810,1813. As the district court noted, trial counsel investigated and presented mitigating evidence. But Hanson maintains that this testimony was insufficient to “humanize” him. Appellant’s Br. at 34. He submitted 13 affidavits from family members and friends who, he argues, would have humanized him in the eyes of the jury. These included: • Charlotte Ward, Hanson’s mother, who would have testified that Hanson was a “good boy” who “just got in with the wrong people and their influence.” Application for Evidentiary Hearing on Sixth Amendment Claim, Case No. D-2006-126, at 18. She would have explained that he was an “excellent father” and a thoughtful and kind son. Id. • Stephen Hanson, John Hanson’s brother, who would have testified that their father’s death was extremely hard on Hanson, causing him to feel like his “world had ended.” Id. at 21. He would have testified that Hanson was a “good person” and a hard worker. Id. • Charmyn Clariett, Hanson’s younger sister, who would have testified that Hanson was a “loving, caring person” whose son adores him and that his “son is his life.” Id. at 24. • Marsha Hollingsworth, Hanson’s cousin, who would have testified that she helped to raise Hanson. She would have stated that the death of Hanson’s father was hard on Hanson and that Hanson “didn’t know how to live without him.” Id. at 26. • Joyce Leake, Marquelle’s grandmother, who would have testified that Hanson “took awfully good care of’ his son. Id. at 28. He “was a very nice young man and so respectful to me.” Id. • Spencer Knowles, Marquelle’s uncle, who would have testified that he has known Hanson for ten to fifteen years and that Hanson “was a good father to his son,” “cared about his family,” and was a generous, “good-souled” person, always there to help. Id. at 30. • Theresa Simmons, Hanson’s ex-sister-in-law, who would have testified that Hanson was reliable, “kind[,] and caring.” When Simmons was going through a divorce, Hanson was “there for” her daughter. Id. at 32. • Melissa Simmons, Hanson’s ex-niece, who would have testified that Hanson was “always nice” to her, that he was “always cooking and cleaning” at their house, and that he looked after his son well. Id. at 34. • Marilyn Wright, Hanson’s mother’s best friend, who would have testified that Hanson was a “loving person, nice[,] and respectful” and that he was helpful and kind. Id. at 36. • Tremaine Wright, Hanson’s good friend and roommate for eight years, who would have testified that Hanson missed his dad a lot, that he was a “good father[,]” but that Miller was a bad influence on him. Id. at 39-41. • Jermaine Wright, Hanson’s childhood Mend, who would have testified that Hanson was a “very respectable guy”; that he was hard working and helpful; that he loved his son more than anything; and that he was a “good father.” Id. at 43. • Jamarro Wright, Hanson’s childhood Mend, who would have testified that Hanson was a family man, who was good with kids and a good father. • Daron Joseph, Hanson’s friend, who would have testified that Hanson had strong “family values,” was a good father, and was “kind-hearted”; and that he was someone who “respects people.” Id. at 48-50. We acknowledge that we would be concerned had Gordon never investigated or spoken with any of Hanson’s close family members. See Wilson, 536 F.3d at 1087 (concluding that counsel was deficient for failing to interview a single family member). The record does not reveal whether Gordon actually interviewed, or attempted to interview, these family members. But we need not face this dilemma because we believe that Hanson was not prejudiced by Gordon’s failure to present these witnesses at trial. Even if Hanson had met the first Strickland prong, he could not show that he was prejudiced by the deficient performance. He contends that the additional witnesses would have provided “unique viewpoints of who John Hanson is and offered necessary narratives of the events that transformed [his] life.” Appellant’s Br. at 30. But we are not persuaded. After comparing the mitigating evidence that was actually presented with the proffered affidavits, we see that the additional mitigating witnesses would have testified to the same themes as the four testifying witnesses: Hanson is a follower; he is a kind and nonviolent person; and he is a good father. This testimony would have been duplicative and thus of only marginal value. See Hooks, 689 F.3d at 1190 (concluding that counsel was not deficient in failing to call a witness because jury may have found that her testimony was “duplicative”); DeRosa v. Workman, 679 F.3d 1196, 1218-19 (10th Cir.2012) (concluding that counsel was not deficient in failing to present additional mitigating evidence because it was in large part “duplicative” of evidence actually presented at trial and so of only marginal value). Many of our cases have refused to find prejudice when the evidence not presented would have been cumulative of the evidence the jury already heard. See Grant v. Trammell, 727 F.3d 1006, 1022 (10th Cir.2013) (listing cases). We conclude that there is not a reasonable probability that the additional mitigating evidence would have impacted the jury’s ultimate decision. We cannot say it was unreasonable for the OCCA to hold that it would not have changed the outcome of Hanson’s trial. Therefore, we affirm the district court’s denial of habeas relief on this claim. v. Failure to present evidence of mental illness and brain damage Hanson next argues that both his trial and appellate counsel provided ineffective assistance by failing at the resentencing hearing and on appeal to properly investigate and present evidence concerning Hanson’s mental-health issues and possible brain damage. He relies on the report prepared by psychologist Dr. Jeanne Russell, Ed.D., for his resentencing hearing, which, he says, flagged multiple indicators of his mental-health issues. He' asserts that this evidence, in conjunction with reports prepared by a psychiatrist and neu-ropsychologist at the habeas stage, would have provided the jury with a fuller picture of Hanson’s mental health status and helped to explain his actions. He believes these reports provide sufficient evidence of his mental-health issues to warrant our reversal of his sentence or, at the very least, to warrant a remand with instructions for the district court to hold an evi-dentiary hearing on the matter. Before engaging in an analysis of the issue, we present the various evaluations that were conducted both before and after the resen-tencing hearing. We then examine and explain why we are unconvinced by Hanson’s argument and reject his request for an evidentiary hearing. Before the 2001 trial, Kathy LaFortune, an in-house psychologist for the Oklahoma Indigent Defense System (“OIDS”), conducted a preliminary screening examination of Hanson. This screening consisted of a basic mental health examination, a Minnesota Multiphasic Personality Inventory, and an abbreviated IQ test. LaFor-tune opined that, based on her examination, a neuropsychologist should not be retained. After the OCCA remanded the case for a new sentencing hearing, Gordon referred Hanson to Dr. Russell, for a social history and risk assessment. Dr. Russell was hired specifically to rebut the continuing-threat aggravator by providing information on Hanson’s background and potential risk for violence while incarcerated. Dr. Russell (1) performed a Minnesota Multiphasic Personality Inventory, a Weschler Abbreviated Scale of Intelligence test, and a Hare Psychopathy Checklist test; (2) interviewed Hanson, his mother, stepfather, and ex-girlfriend; and (3) reviewed various legal documents, including his presentence report and Oklahoma Department of Correction Records. Her report unearthed numerous aspects of Hanson’s background and mental health. Hanson’s parents divorced when he was ten years old and his father died when he was 17. He dropped out of high school after eleventh grade, completing his GED in prison. Dr. Russell observed that Hanson exhibits paranoid thoughts, which impair his ability to trust anyone. The Minnesota Multiphasic Personality Inventory “indicates some confusion and personality deterioration.... [H]e is preoccupied with bizarre ideas and abstract thoughts. He tends to project blame onto others and appears to withdraw into fantasy in an attempt to deal with his distress.” Appendix of Attachments to the Successive Application for Post-Conviction Relief in OCCA case no. PCD-2011-58, Att. 7, at 7. She also observed that his “extreme and bizarre thoughts! ] suggest! ] the presence of delusions and/or hallucinations. He apparently believes that he has special mystical powers or a special ‘mission’ in life that others do not understand or accept.” Id. In conclusion, her psychological testing results showed that his overall intelligence is above average, that he is depressed, and that he feels “estranged and alienated from people and is suspicious of the actions of others.” Id. at 12. At the resen-tencing hearing, she testified that he was a “low risk to society” in prison. Tr. Trans. II, Vol. X at 1758. On direct appeal of his second death sentence, Hanson’s new counsel, Jamie Py-bas, attempted to retain a neuropsychologist to examine Hanson. But after LaFor-tune advised her not to retain one, Pybas abandoned all pursuits. In preparation for his federal habeas petition, Hanson’s new counsel, Robert Jackson, procured a psychiatric evaluation and a neuropsychological evaluation. Hanson submitted reports from these evaluations with his second post-conviction application before the OCCA. The OCCA denied his post-conviction relief, finding his ineffective assistance of counsel claim mer-itless. The OCCA reviewed and acknowledged the evidence Hanson had provided in support of his mental health claims, stating: Hanson provides in support of his current application for relief the January 13, 2011 affidavit of Tora Brawley, Ph. D., and Hanson’s November 29, 2010 psychiatric evaluation conducted by Dr. Donna Schwartz-Watts, M.D. Dr. Braw-•ley conducted a neuropsychological evaluation of Hanson in December 2010 that included a clinical interview, behavior observation and the administration of a battery of standardized tests. Dr. Brawley states that her evaluation revealed the presence of scattered cognitive deficits suggestive of brain organicity. She believes these deficits were present at the time of the murder be-' cause there is no evidence Hanson suffered any trauma since that time to account for these deficits. She states that scores on testing conducted in 2004 should have led to further evaluation of Hanson’s neuropsychological and neurological functioning. Findings of brain organicity, according to Dr. Brawley, can be an important aspect contributing to criminal behaviors and should have been considered in Hanson’s defense during legal proceedings. Dr. Schwartz-Watts concludes that Hanson suffers from Dysthymic Disorder, Major Depressive Disorder, Post Traumatic Stress Disorder, Cognitive Disorder[,] and Paranoid Personality Disorder. Her opinions are consistent with those of Dr. Brawley. Opinion Denying Second Application for PosWConviction Relief and Motion for Evi-dentiary Hearing, PCD-2011-58, Appellant’s Br., Att. I at 7, n. 5. In support of its opinion denying relief, the OCCA stated: According to the materials, Hanson was evaluated early on by the Head of Psychological Services at OIDS at the request of trial counsel, presumably to evaluate' the need for psychological experts. After the screening procedure, a psychologist was retained to perform a risk assessment for Hanson’s original trial. Appellate counsel’s request for a neuropsychologist during Hanson’s direct appeal of his original trial was denied based upon the screening examination conducted before trial. We can only conclude that his screening examination did not suggest the need for neu-ropsychological testing for mental illness and cognitive dysfunction. For Hanson’s resentencing trial, a second risk assessment was performed by another psychologist. There is no evidence before us that either of the psychologists who performed risk assessments of Hanson expressed any concerns to Hanson’s attorneys — as one would think this type of expert would do in a case like this— that Hanson needed further evaluation because their testing revealed indicators of mental health or cognitive dysfunction. We cannot accept as credible Hanson’s assertion that the experienced capital litigation experts and attorneys all missed these obvious indicators of mental illness and cognitive dysfunction in this case at every step. Instead, we think the record shows that the issue of Hanson’s mental health was considered by trial and appellate counsel and they decided not to pursue further mental health investigation in light of the screening test results. This was a reasonable strategy decision under the circumstances. Id. at 5-6 (emphasis added). Because the OCCA reviewed the new evidence, the district court properly analyzed the claim through the lens of AED-PA. Hanson III, 2013 WL 3307111, at *37. It affirmed the OCCA’s holding and agreed with its reasoning that “appellate counsel did not perform deficiently because pretrial mental and social evaluations of [Hanson] did not reveal a need for further evaluation.” Id. at *38. It also concluded that Hanson “was not prejudiced by trial counsel’s failure to further investigate and present evidence of [Hanson’s] mental health issues.” Id. at *39. We agree and hold that neither trial nor appellate counsel was deficient in their investigation and presentation of Hanson’s mental-health issues. As in his previous ineffective assistance of counsel claims, Hanson here must establish both that his attorney’s representation was deficient and that the deficient performance prejudiced his defense. See Hooper v. Mullin, 314 F.3d 1162, 1168-69 (10th Cir.2002). The Supreme Court has expressly held that evidence of mental illness and brain dysfunction are essential components of a defendant’s mitigation case. Boyde v. California, 494 U.S. 370, 382, 110 S.Ct. 1190, 108 L.Ed.2d 316 (1990) (“[E]vidence about the defendant’s background and character is relevant because of the belief ... that defendants who commit criminal acts that are attributable to ... emotional and mental problems, may be less culpable than defendants who have no excuse.” (internal quotation marks omitted)); see also Sears v. Upton, 561 U.S. 945, 956, 130 S.Ct. 3259, 177 L.Ed.2d 1025 (2010) (per curiam) (concluding that trial counsel’s utter failure to uncover evidence of petitioner’s significant mental and psychological impairments was deficient and prejudicial). Mental-health evidence in particular is some of the most valuable mitigating evidence available. See Anderson v. Sirmons, 476 F.3d 1131, 1144 (10th Cir.2007) (stating that mental health' evidence can show that what is going on in a defendant is not necessarily the “meanness” jurors assume). Hanson argues that counsel did not have a strategic reason for failing to investigate the possible mental-health issues flagged in Dr. Russell’s report. “Instead of exploring these markers, counsel simply forged ahead with the lone approach of rebutting the continuing threat aggravator.” Appellant’s Br. at 44. While the OCCA and the district court found that the pretrial mental health evaluations revealed no reason for further testing, Hanson attributes this to the limited evaluations. We are surprised by his argument. His assertion flies in the face of his contemporaneous argument that Dr. Russell’s report flagged multiple indicators of mental-health issues that trial and appellate counsel should have followed up on. He cannot simultaneously contend that the tests were too narrow to reveal his mental health issues and that they raised red flags requiring counsel’s follow-up. Those arguments are intrinsically contradictory. Moreover, studied through the lens of AEDPA’s deference, we do not see how we could disagree with the OCCA’s finding that “we cannot accept as credible Hanson’s assertion that the experienced capital litigation experts and attorneys all missed these obvious indicators of mental health illness and cognitive dysfunction in this case at every step.” Appellant’s Br., Att. I. at 5-6. Hanson received at least two different mental health screenings or evaluations before his resentencing hearing. The evaluations alerted neither the psychologist nor the attorneys to flags indicating Hanson might have mental-health problems. We cannot simply assume that every single member of the defense team missed glaring markers of Hanson’s mental illness. Finally, we refuse Hanson’s request to remand the case to the district court for an evidentiary hearing on this issue. A habeas petitioner can obtain an evidentiary hearing in federal court by “(1) showing he was diligent in developing the factual basis for his claim in state court ...; and (2) asserting a factual basis that, if true, would entitle him to habeas relief.” Boyle v. McKune, 544 F.3d 1132, 1135 (10th Cir.2008) (citations omitted). If the petitioner has exercised diligence in developing the factual basis for his claim, “his request for an evidentiary hearing may be assessed under less-rigorous pre-AEDPA standards.” Littlejohn, 704 F.3d at 857; see also Williams, 529 U.S. at 437, 120 S.Ct. 1479. The preliminary inquiry is whether Hanson was “diligent” in developing the factual basis for his claim. “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.” Williams, 529 U.S. at 437, 120 S.Ct. 1479. Hanson sought to develop his claim in state court. As such, we believe Hanson was diligent in developing the factual basis for his claim. Moving on to the substantive inquiry, we must consider whether Hanson is entitled to an evidentiary hearing on his claim. He is entitled to a hearing so long as his factual allegations, “if true, would entitle [him] to federal habeas relief.” Boyle, 544 F.3d at 1136 (alteration in original) (quoting Schriro v. Landrigan, 550 U.S. 465, 474, 127 S.Ct. 1933, 167 L.Ed.2d 836 (2007)). But he has offered no evidence that his counsel was deficient in relying on the evaluations of two psychological experts, neither of which suggested further testing. Therefore, we deny his request for an evidentiary hearing. vi. Failure to object to prosecutorial misconduct Hanson next argues that there were numerous instances of prosecutorial misconduct to which Gordon failed to object, rendering his counsel ineffective. He contends that the prosecution: (1) inappropriately vouched for Barnes’s credibility; (2) made improper appeals for civic justice; (3) misled the jury about the proof necessary to establish the great-