Affirmed by published opinion. Judge DUNCAN wrote the majority opinion, in which Judge SHEDD joined. Judge GREGORY wrote a separate opinion concurring in part and dissenting in part.
DUNCAN, Circuit Judge.George “Cale” Buckner petitions this court for review of the district court’s denial of his petition under 28 U.S.C. § 2254 for relief from his North Carolina first-degree murder conviction and death sentence. For the reasons that follow, we affirm.
I.
On February 19, 1992, in Gaston County, North Carolina, Buckner’s friends Dennis Eason and Anthony Cathcart drove Buckner and another friend, Jamie Bivens, to the home of Eddie Dow and left them there to wait for Dow. Dow was subsequently robbed and murdered in front of his home, killed by three shots fired from an SKS rifle belonging to Buckner’s brother.
A few days after the murder, Buckner came to the police station for questioning at the request of police. The officers left *197him alone in an unlocked office for several hours, during which time he fell asleep. Officers eventually returned to question Buckner, telling him that Bivens had identified Buckner as Dow’s killer. Buckner responded that he had not killed anyone and requested to speak with his lawyer before making a statement. The police ceased their questions, arrested him, did not read him his Miranda rights, and did not contact the lawyer whom Buckner had requested.
Buckner was charged with, among other crimes, first-degree murder. At his trial, Buckner testified that Bivens had murdered Dow and that he had been present only to gather, in his capacity as a police informant, information about Dow’s drug activities. By contrast, Bivens, Eason, and Cathcart testified that Buckner had been the shooter. In its closing argument, the state challenged Buckner’s version of the events by alluding to his failure to name Bivens as the killer immediately after the crime, during his brief questioning at the police station, or during his pre-trial incarceration when he was writing to law enforcement authorities across North Carolina to offer information about other defendants and crimes about which he had knowledge.1 The jury convicted Buckner *198of first-degree murder under alternate theories of felony murder, lying in wait, and premeditation and deliberation. The trial court imposed the jury’s recommended sentence of death.
After exhausting his direct appeal, Buckner began his state collateral post-conviction appeals, which in North Carolina are brought via a Motion for Appropriate Relief (“MAR”) in the Superior Court (“MAR court”). The MAR court denied relief and the North Carolina Supreme Court affirmed that decision. Buckner then turned to the federal courts, filing a § 2254 petition for habeas relief based on several alleged points of error concerning his conviction and sentence. The district court denied the petition in its entirety but granted a certificate of appealability on Buckner’s Fifth Amendment claim concerning the state’s reference during its closing argument to Buckner’s post-arrest, pre-Miranda silence. This court expanded the certificate to include two additional claims: 1) actual innocence based on new evidence purporting to show that Bivens, not Buckner, was the shooter, and 2) ineffective assistance of counsel at sentencing.2
II.
This court reviews de novo the district court’s denial of Buckner’s petition for a writ of habeas corpus. See Conner v. Polk, 407 F.3d 198, 204 (4th Cir.2005), cert. denied, — U.S.-, 126 S.Ct. 1431, 164 L.Ed.2d 135 (2006). The Anti-Terrorism and Effective Death Penalty Act (“AED-PA”), 28 U.S.C. § 2254 (2000), governs this court’s consideration of Buckner’s challenges to his state conviction and sentence, each of which has already been adjudicated on the merits in state court.
Under the AEDPA’s deferential standard of review, a state court’s adjudication of questions of law warrants issuance of the writ only if such adjudication was “contrary to, or involved an unreasonable application of, clearly established Federal law, as determined by the Supreme Court” or if it was “based on an unreasonable determination of the facts in light of the evidence presented in the State court proceeding.” § 2254(d)(l)-(2). A decision is “contrary to” clearly established federal law if it either applies a legal rule that contradicts prior Supreme Court holdings or reaches a conclusion different from that of the Supreme Court “on a set of materially indistinguishable facts.” Williams v. Taylor, 529 U.S. 362, 412-13, 120 S.Ct. 1495, 146 L.Ed.2d 389 (2000). A decision is an “unreasonable application” of clearly established federal law if it “unreasonably applies” a Supreme Court precedent to the facts of the petitioner’s claim. Id. at 413,120 S.Ct. 1495.
In deciding whether a petitioner has demonstrated the deficiency of the state court adjudication under § 2254(d), federal courts must presume state court findings of fact to be correct unless the petitioner rebuts that presumption by clear and convincing evidence. § 2254(e)(1).
III.
Buckner first requests habeas relief based upon new evidence that he claims proves his actual innocence of mastermind*199ing the robbery and shooting Dow. The MAR court summarily denied this claim on state law grounds without consideration of its possible federal constitutional dimensions. The district court denied the claim, concluding that it was not cognizable on federal habeas review. We also deny relief.
A.
At the MAR hearing, Buckner offered affidavits and testimony from jailhouse informants who claimed that Bivens, Eason, and Catheart all named Bivens as the person who had planned the robbery and shot Dow. Buckner also offered the testimony of an eyewitness who claimed that, when she saw Bivens a few hours after the robbery and murder, Bivens looked agitated and declared that he had “got [him] a piece” of Dow. (J.A. at 86.) He claims that this new evidence demonstrates his actual innocence of facts necessary to sustain his conviction and sentence.
Habeas petitioners may use an actual innocence claim to excuse the procedural default of a separate constitutional claim upon which they request habeas relief. Murray v. Carrier, 477 U.S. 478, 496, 106 S.Ct. 2639, 91 L.Ed.2d 397 (1986) (“[When] a constitutional violation has probably resulted in the conviction of one who is actually innocent, a federal habeas court may grant the writ even in the absence of a showing of cause for the procedural default.”); see also Reid v. True, 349 F.3d 788, 806 (4th Cir.2003). These so-called “gateway” innocence claims may be based upon evidence of the petitioner’s innocence of the crime for which he was convicted, see, e.g., Schlup v. Delo, 513 U.S. 298, 326-27, 115 S.Ct. 851, 130 L.Ed.2d 808 (1995), or of the sentencing factors that rendered him eligible for the death penalty, see, e.g., Sawyer v. Whitley, 505 U.S. 333, 350, 112 S.Ct. 2514, 120 L.Ed.2d 269 (1992).
However, as the district court recognized, the Supreme Court has strongly suggested that claims of actual innocence standing alone do not serve as an independent basis for habeas relief: “Claims of actual innocence based on newly discovered evidence have never been held to state a ground for federal habeas relief absent an independent constitutional violation occurring in the underlying state criminal proceeding.” Herrera v. Collins, 506 U.S. 390, 400, 113 S.Ct. 853, 122 L.Ed.2d 203 (1993). Citing Herrera, in Rouse v. Lee, 339 F.3d 238, 255 (4th Cir.2003), this court noted that “claims of actual innocence are not grounds for habeas relief even in a capital case.”
While acknowledging authority to the contrary, Buckner nevertheless contends that the point is subject to debate. According to Buckner, Herrera does not completely foreclose free-standing claims of actual innocence. We need not address the issue here, however. As the Supreme Court has suggested, and Buckner recognizes, if free-standing actual innocence claims were cognizable on federal habeas review, “the threshold showing for such an assumed right would necessarily be extraordinarily high.” Herrera, 506 U.S. at 417, 113 S.Ct. 853. On the facts before us, Buckner has failed to meet even the presumptively less stringent standard of proof by which gateway innocence claims are measured.
B.
Buckner’s new evidence does not establish his actual innocence of first-degree murder. Petitioners who wish to use a claim of actual innocence as a gateway to raising an otherwise defaulted constitutional claim must demonstrate by a preponderance of the evidence that a reason*200able juror could not have convicted the petitioner in light of the new evidence. See Schlup, 513 U.S. at 327, 115 S.Ct. 851. The jury found Buckner guilty of first-degree murder under three separate theories, including felony murder.3 As the district court recognized, Buckner’s “evidence speaks only to whether he or Bivens pulled the trigger; it has no bearing upon the evidence presented at trial that [he] was an active and willing participant in the robbery of Eddie Dow.” (J.A. at 749.) New evidence that merely undermines the state’s theory of the case but does not rebut specific jury findings of guilt is insufficient to demonstrate actual innocence. See Herrera, 506 U.S. at 418-19, 113 S.Ct. 853. Because Buckner was convicted under a theory of felony murder and has provided no evidence contradicting his guilt of Dow’s robbery or the connection between that robbery and Dow’s death, he has not stated a viable free-standing claim of actual innocence of first-degree murder.
C.
Similarly, Buckner’s new evidence does not demonstrate his innocence of capital felony murder. Felony murder is a capital crime only if the defendant killed, intended to kill, intended that a killing take place or that lethal force be employed, or participated so significantly in the underlying felony that he exhibited reckless indifference to human life. Enmund v. Florida, 458 U.S. 782, 797, 102 S.Ct. 3368, 73 L.Ed.2d 1140 (1982); Tison v. Arizona, 481 U.S. 137, 158, 107 S.Ct. 1676, 95 L.Ed.2d 127 (1987). The jury’s sentencing recommendation of death in this case was predicated upon its threshold finding that one or more of these capital felony murder factors applied to Buckner. In the context of capital sentencing, a viable gateway innocence claim demonstrates by clear and convincing evidence that, but for the defaulted constitutional error, no reasonable juror would have found the petitioner eligible for the death penalty. See Sawyer, 505 U.S. at 350, 112 S.Ct. 2514. In other words, the new evidence must establish by clear and convincing evidence Buckner’s innocence of any sentencing factor that made him eligible for capital punishment.4
Buckner’s new evidence, if credible, might demonstrate his innocence of killing, intending to kill, intending that a killing take place, or intending that lethal force be employed. However, even assuming that the new evidence conclusively shows that Bivens planned the robbery and shot Dow, it does not show that no reasonable juror could have found that Buckner’s participation in the robbery rose to the level of reckless indifference to human life. The *201jury heard evidence, none of which the new evidence contradicts, that Buckner was aware of Bivens’ plan to rob Dow, that he was present at the robbery and murder, that he participated in the robbery, that he helped to conceal the crime by disposing of evidence, and that, despite having time and opportunity to do so, he did not report the crime to the police. This evidence is sufficient to support a jury finding that Buckner’s participation in Dow’s robbery constituted reckless indifference to human life. See, e.g., Tison, 481 U.S. at 151-52, 157-58, 107 S.Ct. 1676; (defendants who knew beforehand that their accomplices were likely to commit murder, who robbed the victims at their accomplices’ direction, and who stood by while the murders were committed were guilty of capital felony murder). We therefore find Buckner’s new evidence insufficient to demonstrate his actual innocence of capital felony murder.
IV.
Buckner next requests habeas relief based on his argument that he received ineffective assistance of counsel during the sentencing phase of his trial. The MAR court denied this claim after a hearing. The district court also denied relief, as do we.
A.
Buckner claims that his counsel failed to investigate, discover, develop, and present mitigating evidence that might have convinced the jury not to recommend a death sentence. To demonstrate that he received ineffective assistance of counsel at his sentencing, Buckner must show that (1) his attorney’s performance “fell below an objective standard of reasonableness” and (2) a reasonable probability exists that, but for the deficient performance, he would not have been sentenced to death. Strickland v. Washington, 466 U.S. 668, 687-88, 694, 104 S.Ct. 2052, 80 L.Ed.2d 674 (1984). Even assuming, without deciding, that the performance of Buckner’s trial counsel was unreasonable, we agree with the MAR court that Buckner has not demonstrated the requisite prejudice.
B.
Under the first prong of Strickland, Buckner must show that his counsel’s performance at sentencing “fell below an objective standard of reasonableness” based on the situation at the time rather than on hindsight. Strickland, 466 U.S. at 688-90, 104 S.Ct. 2052. Counsel’s conduct is generally presumed to be a reasonable strategic choice, but is not reasonable to the extent that the choice of strategy does not rely upon either a full investigation of the law and facts or an abbreviated investigation of the law and facts limited only by “reasonable professional judgments.” Id. at 690-91,104 S.Ct. 2052.
Buckner claims that his lead counsel for the sentencing phase of the trial, David Childers, spent an unreasonably short amount of time preparing for sentencing and consequently failed to uncover and present to the jury mitigating factors concerning his background and mental health. At the MAR hearing, Childers testified that he conducted “the bulk” of his work for the sentencing phase beginning approximately one and one-half months before trial. (J.A. at 135.) He also explained that he had initially focused his efforts on developing evidence that Buckner was not the shooter and that he turned his attention to preparing mitigation evidence during the guilt phase of the trial, only one week before the sentencing phase began. Finally, during this time Childers was also solely responsible for responding to an IRS deficiency investigation that had the potential to put his law partnership out of business and “take everything [he] had.” *202(J.A. at 129.) Childers was consumed by his efforts to secure a loan to pay the partnership’s sizeable tax bill, to meet with the IRS investigators, and to juggle the partnership’s other unpaid bills.
Accepting Childers’ statement that the bulk of the work in preparation for mitigation occurred during the week that he was also participating in the guilt phase of the trial and handling his partnership’s IRS difficulties, his efforts were certainly less than optimal. Strategies based upon counsel’s unreasonably short preparation time rather than upon reasoned professional judgment can, in some circumstances, constitute deficient performance of counsel under the Strickland standard. See Wiggins v. Smith, 539 U.S. 510, 526, 123 S.Ct. 2527, 156 L.Ed.2d 471 (2003) (finding ineffective assistance of counsel in part because inattention rather than professional judgment guided counsel’s conduct).5 Because we hold that Buckner was not prejudiced by Childers’ lack of preparation, however, we need not decide whether his performance was constitutionally deficient.6
*203c.
The second prong of the Strickland standard compels Buckner to demonstrate a “reasonable probability,” or by somewhat less than a preponderance of the evidence, that, but for the alleged constitutional deficiency in Childers’ representation, he would not have been sentenced to death. Strickland, 466 U.S. at 694,104 S.Ct. 2052. A reasonable probability that, despite Buckner’s legal eligibility for the death penalty, one juror considering the original and newly raised evidence together would have voted for life imprisonment satisfies this standard. See Wiggins, 539 U.S. at 536-37, 123 S.Ct. 2527. To recommend death over life imprisonment, North Carolina juries must unanimously find that mitigating factors do not outweigh aggravating factors.7 N.C. Gen.Stat. § 15A-2000(c) (2005). Buckner therefore must demonstrate a reasonable probability that at least one juror would have found that his new mitigating evidence, combined with the existing mitigating evidence, outweighed the aggravating circumstances surrounding Dow’s death.
Even if on de novo review we might strike a different balance concerning the relative weight of the aggravating and mitigating evidence, we may not disturb the MAR court’s conclusion that Buckner did not demonstrate prejudice unless we find that conclusion to be unreasonable in light of clearly established Supreme Court precedent or in light of the evidence before the MAR court. See § 2254(d)(l)-(2). When determining whether Buckner has satisfied one of these two standards, we must presume the MAR court’s factual findings to be correct unless Buckner provides clear and convincing evidence to the contrary. See § 2254(e)(1).
At the MAR proceedings and before the district court, Buckner argued that Childers’ mitigation presentation had prejudiced him because it did not include a fuller treatment of the difficult circumstances of his childhood and how those circumstances had helped to shape his emotional immaturity. He supported this claim with affidavits from Cynthia Maxwell, a mitigation specialist; Nathan Strahl, a psychiatrist; and Claudia Coleman, a psychologist. According to Buckner, these affidavits detailed the mitigation evidence that Childers could have discovered had he devoted a reasonable amount of time to preparation and made reasonable decisions in response to the information that he did uncover. In short, Buckner claimed that these affidavits established a reasonable probability that he would have received a life sentence absent Childers’ errors.
The MAR court determined that the Maxwell, Strahl, and Coleman affidavits were “not credible” because Buckner and his family were “now motivated to take a different tact [sic] by an imposed sentence of death.” (J.A. at 453.) The dissent posits that the MAR court mistakenly discounted the affidavits’ credibility, arguing that counsel’s failure to impress upon Buckner and his family the importance of cooperating with the mitigation investigation, not their belief in the truth of their original statements, was responsible for the delay in uncovering the new information. He concludes that the MAR court *204rejected the affidavits “simply because they relied on information obtained from Buckner and his family following his conviction.” Infra p. 224.
This conclusion has no apparent basis in the record. The MAR court did not reject the Maxwell, Strahl, and Coleman affidavits because the information upon which they were based was gathered after his conviction, but because the same people who provided that new information had provided directly contradictory stories to counsel prior to and at trial. The MAR court found that Buckner had told his counsel that he had no mental or emotional problems, that Buckner repeatedly refused to cooperate with evaluating psychologists, and that he “was adamant ... that the tragedies in his life did not affect him mentally or emotionally.” (J.A. at 453.) It further concluded that counsel’s background investigation uncovered evidence that Buckner was not abused as a child and that he “was raised by loving parents.” Id. In addition, the MAR court found that one of Buckner’s attorneys, “who had a long-standing relationship with [Buckner], did not see any evidence of medical or mental problems.” (J.A. at 453.) Finally, Buckner’s mother testified at sentencing that Buckner had a good childhood relationship with his father and that nothing marked Buckner’s childhood as particularly difficult. Buckner has made little attempt to explain why his and his family’s stories have changed or why the newly minted versions of Buckner’s childhood and mental health are more reliable than the originals. Indeed, he has argued only that he and his family did not fully understand the gravity of the situation prior to trial. This lone argument, coupled with the absence of any explanation for the contradictory stories, suggests that the MAR court’s credibility finding was in fact correct. Even drawing only favorable inferences from his argument, we cannot say that these inferences rebut the state court’s credibility finding by clear and convincing evidence.8
Further, even if we could surmount the barrier of the MAR court’s adverse credibility finding to consider the new information in the. affidavits, we think that neither Strickland nor its Supreme Court progeny contravene the MAR court’s conclusion that Buckner suffered no constitutionally cognizable prejudice from Childers’ representation. Indeed, an examination of the proffered evidence suggests that it differs primarily in degree rather than in kind from the evidence that Childers presented.
The Maxwell affidavit recounts several aspects of Buckner’s childhood and young adulthood that Childers did not raise or raised in less detail during sentencing. For example, it describes general neglect and emotional abuse by both parents, Buckner’s father’s physical abuse of his mother when Buckner was a child, his mother’s alcoholism during his childhood, his mother’s rumored sexual relationship with a female friend who lived with the family during his adolescence, his lack of regular medical and dental care as a child, the death of his father in 1991, and his mother’s diagnosis of ovarian cancer. Maxwell also recounted in detail the story of the death of Buckner’s brother in the house fire, the injury of his father in the fire, and the father’s inability to save the *205younger brother. As a result of 'witnessing these events, according to Maxwell, Buckner developed nightmares and a sleepwalking disorder for which he received no mental health care or counseling.
The Strahl affidavit opined that at the time of Dow’s murder Buckner had the emotional maturity of a twelve-year-old. Strahl also asserted that Buckner lacked mature reasoning and decision-making skills, that he harbored a need for acceptance and was easily influenced by others, and that these emotional deficiencies “contributed materially” to Buckner’s involvement in Dow’s death. (J.A. at 293.) Strahl concluded that, with treatment, Buckner could ameliorate these problems and become a constructive individual. The Coleman affidavit contains findings similar to those in the Maxwell and Strahl affidavits.9
In determining that Childers’ performance at sentencing did not prejudice Buckner, the MAR court pointed to the existing mitigation evidence touching on various aspects of Buckner’s life, from his family history to his activities as a police informant. Childers portrayed Buckner as the product of a troubled home, whose father had a history of alcohol abuse and whose brother died in a house fire when Buckner was young. He presented evidence of Buckner’s personality and values, including testimony describing him as a person who “[gets] along well with others,” who “especially [likes] children,” and who was a hardworking employee. Childers also detailed Buckner’s assistance in the prosecution of several people for criminal offenses, including murder. By contrast, the MAR court found that the state had presented “overwhelming evidence” in support of a sentence of death.10 (J.A. at 454.)
Although Buckner and the dissent disagree with the MAR court’s conclusion that Buckner suffered no prejudice, neither has shown that this conclusion was unreasonable in light of clearly established Supreme Court precedent. A review of the decisions in which prejudice has been found presents a stark contrast with the type of evidence presented by Buckner. In Williams, for example, the Supreme Court found prejudice from counsel’s failure to present at sentencing any evidence of the defendant’s “nightmarish childhood,” which included a home littered with urine, feces, and trash; lack of basic hygienic care from his parents; the imprisonment of both alcoholic parents for criminal neglect of the defendant and his siblings; severe and repeated physical abuse of the defendant by the defendant’s father; and *206two years in the custody of social services during which he spent time in an abusive foster home. 529 U.S. at 395 & n. 19, 120 S.Ct. 1495. Though the prosecution had presented extensive evidence of the defendant’s potential for future dangerousness, including expert testimony and his criminal history of armed robbery, burglary, grand larceny, violent assaults on elderly victims, and arson, the Court found that this new evidence, in conjunction with the existing evidence detailing the defendant’s actions alerting police to his crime and cooperating with the investigation, could have altered the jury’s “appraisal of [the defendant’s] moral culpability.” Id. at 398, 120 S.Ct. 1495.
The Court in Wiggins similarly found prejudice from counsel’s failure to alert the jury to defendant’s borderline mental retardation and severe childhood physical and sexual abuse, which included neglect by his alcoholic mother, who would abandon him for days during which he would beg for food and eat paint chips and garbage; beatings for breaking into his mother’s locked kitchen; hospitalization after his mother had forced his hand against a hot stove; physical abuse by two different foster mothers; repeated rapes and molestation by a foster father; multiple gang rapes by a third foster mother’s sons; sexual abuse by a Job Corps supervisor; and homelessness during a period of his adolescence. 539 U.S. at 516-17, 534-35, 123 S.Ct. 2527. Weighing this new evidence and the existing evidence of the defendant’s lack of a criminal history against the details of the defendant’s murder of an elderly woman, the Court found that the defendant was prejudiced by counsel’s unreasonable performance. Id. at 534-38, 123 S.Ct. 2527.
The Maxwell and Coleman affidavits discussing Buckner portray a childhood marked by dysfunctional relationships and sub-optimal care. Even taken as true, however, they do not describe the type of severe and prolonged child abuse and profound psychological disturbances that were present in Wiggins and Williams. Similarly, the Strahl and Coleman affidavits opine that Buckner had the emotional maturity of a twelve-year-old at the time of the crime and that this immaturity led him to make poor decisions that culminated in his participation in Dow’s robbery and murder. This evidence nevertheless does not compare to the borderline mental retardation about which Wiggins’ jury was not informed.
Furthermore, this circuit has upheld as not unreasonable state court applications of Strickland finding no prejudice from counsel’s failure to introduce evidence adding negligible detail or credibility to mitigating factors that counsel had already presented to the jury. McHone v. Polk, 392 F.3d 691, 709-10 (4th Cir.2004) (no prejudice from counsel’s failure to present evidence that as a child petitioner had witnessed his father “regularly inflict brutal beatings” on his mother and half-sister when counsel had presented evidence that petitioner’s father had engaged in “violent fights” with his mother); Tucker v. Ozmint, 350 F.3d 433, 442-43 (4th Cir.2003) (no prejudice from counsel’s failure to present evidence undermining prosecution’s argument that defendant had fabricated his claims of childhood physical and sexual abuse because prosecution and defense witnesses uniformly agreed that petitioner had suffered such abuse).
On de novo review of a § 2254 claim, we reached a similar conclusion that counsel did not prejudice the petitioner by his failure to present additional evidence that was merely cumulative of the existing case in mitigation. See Moody v. Polk, 408 F.3d 141, 154 (4th Cir.2005) (no prejudice from counsel’s failure to present more evi*207dence concerning petitioner’s childhood abuse because one expert and two family members testified that the abuse claims were accurate and the prosecution presented no evidence contradicting that testimony), cert. denied, — U.S. -, 126 S.Ct. 1060, 163 L.Ed.2d 885 (2006).
To the extent that the Maxwell and Coleman affidavits provide new detail of the stories of Buckner’s brother’s death and his father’s alcoholism, we conclude that this new detail is largely cumulative. The affidavits contend that after the fire Buckner received no counseling and suffered from nightmares and sleepwalking for a period of time. They further assert that Buckner’s alcoholic father emotionally neglected him and that his mother would sometimes take the children away from the house when his father was drinking. None of these details adds significant color to the inherently tragic circumstances of losing a sibling or living with an alcoholic parent. The MAR court found that Childers had presented both of those issues to the jury. We are thus unable to conclude that these additional details would have added measurably to Buckner’s mitigation case.
Weighing the evidence of Buckner’s history of criminal violence and of the circumstances surrounding Dow’s murder against the existing mitigation evidence, Buckner’s jury concluded that the mitigating circumstances did not outweigh the aggravating circumstances concerning the events of Dow’s robbery and murder. Even assuming arguendo that the MAR court was wrong to discount Buckner’s new evidence as unreliable, we cannot say that the MAR court contravened Strickland in concluding that Buckner had not shown a reasonable probability that a juror would have changed that calculation based on Buckner’s new evidence. At best, that new evidence paints a picture of a non-organic emotional immaturity and rounds out the details of a personal history already presented to the jury.
V.
Finally, Buckner requests habeas relief based upon the state’s closing arguments referencing his post-arrest silence, which he claims violated his Fifth Amendment right to be free from self-incrimination. On direct appeal, the North Carolina Supreme Court found that the state’s references to Buckner’s silence were for the permissible purpose of impeaching Buckner’s trial testimony and denied the claim. State v. Buckner, 342 N.C. 198, 237-38, 464 S.E.2d 414 (1995). The district court denied the claim on the same grounds, as do we.11
*208Well-settled law prohibits states from using a defendant’s post -Miranda silence to impeach that defendant’s testimony providing an exculpatory version of the events in question. See Doyle v. Ohio, 426 U.S. 610, 619, 96 S.Ct. 2240, 49 L.Ed.2d 91 (1976). However, states may use a defendant’s pre-Miranda silence, whether it occurred before or after arrest, to do so. See Fletcher v. Weir, 455 U.S. 603, 607, 102 S.Ct. 1309, 71 L.Ed.2d 490 (1982) (per curiam) (concerning post-arrest, pre-Miranda silence); Jenkins v. Anderson, 447 U.S. 231, 240-41, 100 S.Ct. 2124, 65 L.Ed.2d 86 (1980) (Stevens, J., concurring) (concerning pre-arrest silence).
We agree with the MAR court and the district court that the prosecutor’s references to Buckner’s silence were for the permissible purpose of impeachment. Through his testimony Buckner attempted to exculpate himself by claiming that he had been present at Dow’s robbery and murder as a police informant rather than as a participant. His pre-Miranda refusal to offer his version of the events to the police is probative of the truthfulness of that testimony. The fact that Buckner’s testimony concerned his guilt does not insulate it from impeachment, even if in the state’s case-in-chief the Fifth Amendment would bar the impeaching evidence or line of inquiry. See, e.g., Harris v. New York, 401 U.S. 222, 225-26, 91 S.Ct. 643, 28 L.Ed.2d 1 (1971) (statements obtained in violation of Miranda may be used to impeach a defendant’s testimony, even if that testimony bears “directly on the crimes charged” rather than on collateral matters).
Indeed, the Supreme Court’s jurisprudence in this area has principally involved impeachment targeting the defendant’s exculpatory testimony, rather than impeachment concerning more collateral matters. Doyle made clear that, while the state could not use the defendant’s post-Miranda silence to impeach his exculpatory testimony, it nevertheless could use such evidence to impeach his testimony that he had not been silent at a particular time. 426 U.S. at 619 n. 11, 96 S.Ct. 2240. Fletcher and Jenkins later held that Doyle’s prohibition on the use of post -Miranda silence does not apply to pre-Miranda silence. 455 U.S. at 607, 102 S.Ct. 1309, 447 U.S. at 241, 100 S.Ct. 2124. Because the prosecutor’s closing argument used Buckner’s pre-Miranda silence to impeach his exculpatory testimony, we find that the prosecutor’s remarks during closing arguments did not violate the Fifth Amendment.
VI.
For the foregoing reasons, we affirm the district court’s denial of Buckner’s petition for relief from his North Carolina conviction and sentence. The judgment of the district court is
AFFIRMED.
. In reference to Buckner’s silence immediately after the crime and after police questioning about the murder, the prosecutor asked the jury:
Why doesn’t he tell the police? Why doesn’t Mr. Buckner say anything to the police? He doesn't give a statement. When the police come to him and say, you know, "Jamie's over there, says you're the trigger man," he says, "I didn't shoot anybody; I don't know anything." Put yourself in that position. You didn't do a murder and someone accuses you. What's the first words out of your mouth if you know who the murderer was? The person’s name. Why is Mr. Buckner not saying, "Jamie Bivens did the shooting”? Because Jamie Bivens didn't do the shooting.
(J.A. at 342.) The prosecutor continued, saying "[the police] tried to talk to Mr. Buckner, but he didn’t want to talk to them.” (J.A. at 348.)
In reference to Buckner's silence when he was at the police station awaiting questioning, the prosecutor told the jury:
That Sunday, when Jamie Bivens tells what Mr. Buckner did, when Jamie Bivens goes out to the scene and starts showing them where evidence was at, Cale Buckner could've done the same thing. Cale Buckner could've made a statement saying Jamie Bivens was the person who did the shooting. Cale Buckner could’ve volunteered to go out and show where evidence was. He didn't; he didn’t. And how do you know he’s the trigger man, Ladies and Gentlemen? Think about this; think about this. Put yourself in the role of Mr. Bivens or Mr. Buckner. You were out there, whether you did the shooting or you participated. The police are waiting for you when you arrive back at the house; they said they want to talk to you about Eddie Dow’s death. And you go to the county police department and what’s going to be your reaction? Your heart's going to be racing because you knew ... you were out there at the scene. You’re going to be nervous about what's going to happen, especially if you're the one who’s just along for the ride. But what does Mr. Buckner do? Does he show his concern? He falls asleep. Mr. Cool, Mr. Confident, Mr. Big-Time Police Informant, doesn't have a thing to worry about. He thinks he's got it all wrapped up, so he goes to sleep. The person who didn’t do the killing is going to be real nervous; he ain't going to be falling asleep. The person who didn’t do the killing or ... wasn't the trigger man is going to want his message told to the police. Mr. Buckner didn't tell them.
(J.A. at 343-45.)
In reference to evidence that while he was awaiting trial Buckner wrote to the police about other crimes, the prosecutor told the jury;
[H]e writes all those authorities, Dare County, Alleghany County, Nash County, Forsyth, Pitt, you know, where — never wrote Gaston County to say Jamie Bivens really did the shooting. He's got all that time to write all these other counties and he never writes and says Jamie Bivens did the shooting, because Jamie Bivens didn’t do the shooting.
*198(J.A. at 341.)
. After Buckner's attorneys filed his petition to expand the certificate of appealability, Buckner wrote this court to request that we also consider his claim that his state court conviction violated the Fifth Amendment grand jury clause because his indictment listed the elements of second-degree murder, but he was convicted of first-degree murder. We declined to grant a certificate of appealability as to that issue.
. North Carolina law defines the felony murder theory by reference to the defendant’s participation in a predicate felony. See N.C. Gen.Stat. § 14-17 (2005) ("A murder ... which shall be committed in the perpetration or attempted perpetration of any ... robbery ... [is] murder in the first degree.... ”).
. Though Buckner's new evidence of actual innocence might also have affected the jury’s determination that the mitigating evidence did not out-weigh the aggravating factors, the addition of more persuasive mitigation evidence would not have made Buckner constitutionally ineligible for the death penalty. Albeit in the context of a gateway innocence claim, the Supreme Court has rejected an invitation to expand the actual innocence standard to include demonstrations that new mitigating evidence makes it unlikely that the jury would have opted for death. See Sawyer, 505 U.S. at 343-47, 112 S.Ct. 2514. Given the Court’s indication that free-standing actual innocence claims, if cognizable at all on federal habeas review, would be subject to even higher standards of proof than their gateway counterparts, see Herrera, 506 U.S. at 417, 113 S.Ct. 853, we cannot conclude that the new evidence's speculative effect on the jury’s sentencing recommendation provides a basis for habeas relief.
. We nevertheless recognize the constraints under which Childers was compelled to function. The record shows that he attempted to withdraw as Buckner’s counsel when it became clear that his partnership's financial difficulties would unacceptably interfere with his representation, but the state trial court denied his motion.
. Our conclusion with respect to the prejudice prong of the Strickland standard obviates the need to decide the reasonableness prong. In light of our respected colleague's expansive dissent, however, we feel compelled to point to other evidence of record, considered by the MAR court, that more fully reflects counsel’s efforts.
First, the MAR court heard evidence that, while Buckner's counsel did most of his mitigation work during the final week of the guilty phase of the trial, he did begin his mitigation efforts, at least generally, in the late spring or summer of 1992, approximately fifteen months before Buckner's trial began in September of 1993.
Moreover, while Childers certainly could have done more, the dissent’s assertion that his conduct “fell far below an objective standard of reasonableness,” infra p. 36, is hard to reconcile with the MAR court's extensive findings of fact, which we must presume to be correct unless rebutted by clear and convincing evidence. See § 2254(e)(1). The MAR court found that, during Childers' mitigation preparation, he met with individuals at the North Carolina Center for Death Penalty Litigation and hired a psychologist to interview Buckner. That psychologist failed to obtain any information because of Buckner's repeated refusals to cooperate and insistence that he had no mental or emotional problems and that no events in his childhood had adversely affected him. Buckner's other attorney, a Mr. Bell, had a lengthy relationship with Buckner and did not see any evidence of mental or medical problems. The MAR court also heard evidence that, despite those rebuffs, Childers made further efforts to obtain a psychological evaluation and that he ultimately succeeded in obtaining a pretrial evaluation. At counsel’s request, the trial court also appointed an investigator to assist in obtaining interviews to develop mitigation evidence. After a full review of the facts, including those specifically found by the MAR court, we question the dissent’s assertion that clearly established Supreme Court precedent requires more.
Further, as the MAR court found, Childers did not present psychological mitigating evidence for a variety of reasons, some of them strategic. Defense counsel developed evidence from the defendant and his own family that he was raised by caring parents and was neither mentally nor emotionally abused. Finally, and perhaps most significantly, the MAR court concluded that presenting evidence of Buckner's mental problems would have run counter to the defense theory during the guilt phase that he had been "an extremely competent informant who survived in a highly dangerous world of 'police informants.’ " (J.A. at 453.) Strickland clearly instructs us as to the inappropriateness of second-guessing decisions regarding trial strategy. 466 U.S. at 690, 104 S.Ct. 2052 ("[Courts] should recognize that counsel is strongly presumed to have rendered adequate assistance and made all significant decisions in the exercise of reasoned profes*203sional judgment.... [Strategic choices made after thorough investigation of law and facts relevant to plausible options are virtually unchallengeable. ...”).
. Though not directly relevant to our analysis of Buckner's burden of proof, capital juries in North Carolina must also unanimously find that the aggravating factors are "sufficiently substantial” to warrant a sentence of death. N.C. Gen.Stat. § 15A-2000(c) (2005).
. The dissent asserts that Buckner and his family’s contradictory statements do not necessarily undermine the credibility of the affidavits because neither Buckner nor any member of his family is a mental health expert, but fails to recognize that, under AEDPA, our task is not to decide the credibility issue de novo but to determine whether Buckner has produced clear and convincing evidence that the MAR court's resolution of that issue was incorrect.
. Large portions of the Coleman and Maxwell affidavits share identical language. It is clear that one of the affiants borrowed heavily from the statements of the other, a fact that lends weight to the MAR court’s finding that the purportedly independent professional opinions expressed in these affidavits were not credible.
. In hypothesizing about the existence of prejudice, the dissent asserts that "this was not an open-and-shut case of overwhelming guilt,” infra p. 224, suggesting that the evidence in aggravation was so paltry that the MAR court was unreasonable to conclude that Buckner’s new mitigating evidence did not satisfy Strickland. The dissent predicates this speculation upon the fact that at least one juror noted the involvement of two people in the murder as a mitigating factor.
In addition to ignoring the MAR court’s assessment that the evidence in aggravation was "overwhelming,” the dissent’s argument founders completely upon the fact that the jury found Buckner guilty of first-degree murder under a theory of felony murder, which, as we have noted, is a capital offense under North Carolina law. § 14-17. The jury’s finding that another person (presumably Bivens) in addition to Buckner had been involved in the murder does nothing to undermine the evidence of the circumstances surrounding Buckner's commission of felony murder.
. The district court further concluded that, even if the prosecutor’s references were construed to be part of the state’s case-in-chief, Buckner’s claim still lacked merit. It found that, because of the split of authority in the courts of appeals and the absence of clear Supreme Court authority, the MAR court's refusal to prohibit the use of a defendant’s pre-Miranda silence in the state's case-in-chief was not an unreasonable application of Supreme Court precedent and therefore should not be disturbed on federal habeas review. However, the MAR court merely held the claim procedurally barred because the North Carolina Supreme Court had already adjudicated it on direct appeal. For its part, the North Carolina Supreme Court ruled only on the question of the use of a defendant's preMiranda silence for the purpose of impeachment; it did not rule on the alternative question concerning the use of a defendant’s preMiranda silence in the state’s case-in-chief. See Buckner, 342 N.C. at 222-24, 464 S.E.2d 414. Because we conclude that both the North Carolina Supreme Court and the district court correctly found the prosecutor’s references to Buckner’s silence to be in the nature of impeachment, we need not decide whether the state could have used that silence in its case-in-chief.