Full opinion text
STEPHEN H. ANDERSON, Circuit Judge. Gary Lee Davis appeals from the district court’s denial of his first petition for a writ of habeas corpus, in which he seeks to overturn his sentence of death. We granted Mr. Davis’s request for a certificate of probable cause and a stay pending appeal. We hold as follows: (1) Mr. Davis was not abandoned by his attorney in the closing argument of the penalty phase of his trial; (2) Mr. Davis suffered no prejudice from his attorney’s failure to pursue and present certain additional mitigating evidence in the penalty phase; (3) the statutory aggravators presented to the jury were either valid or, if invalid or otherwise erroneously submitted to the jury, were harmless; (4) the penalty, phase jury instructions neither misled nor confused the jury concerning its evaluation of mitigating evidence; and (5) no error occurred in the removal for cause of three prospective jurors. We therefore affirm the denial of Mr. Davis’s habeas petition. BACKGROUND In July 1986, in Byers, Colorado, Gary Davis and his then-wife, Rebecca Fincham Davis, kidnaped, sexually assaulted and murdered Virginia May. Mr. Davis has never challenged his conviction for that crime, nor does he dispute his involvement in it. The tragic facts concerning this crime have been fully set out in the state court opinions affirming Mr. Davis’s conviction and sentence on direct appeal and in state post-conviction proceedings. People v. Davis, 849 P.2d 857 (Colo.Ct.App.1992) (Davis II), aff'd) 871 P.2d 769 (Colo.1994) (Davis III); People v. Davis, 794 P.2d 769 (Colo.1990) (Davis I), cert. denied, 498 U.S. 1018, 111 S.Ct. 662, 112 L.Ed.2d 656 (1991). We refer to facts concerning the crime only as necessary in our discussion of particular issues. Mr. Davis and Ms. Fincham were tried separately. The state sought the death penalty against Mr. Davis but not Ms. Fincham. When Mr. Davis’s appointed state public defender had to withdraw because of a conflict of interest, Craig Truman was appointed Mr. Davis’s counsel. Against Mr. Truman’s advice, Mr. Davis testified before the jury during the guilt/innocence phase of the trial, stating that he had kidnaped, assaulted and murdered Ms. May, and emphasizing his own culpability over that of Ms. Fincham. The jury found Mr. Davis guilty' of murder in the first degree after deliberation; felony murder; conspiracy to commit murder in the first degree; second degree kidnaping; and conspiracy to commit second degree kidnap-ing. He was sentenced to life imprisonment on the conspiracy and second degree kidnap-ing convictions. The penalty phase for the murder convictions began the day after the guilt/innocence phase concluded. The jury was presented with six aggravating factors and eight mitigating factors. It found all six aggravating circumstances proven and made no findings on the existence of any mitigating factors. The jury concluded beyond a reasonable doubt that death was the proper punishment. In his direct appeal, Mr. Davis challenged his sentence on numerous grounds. The Colorado Supreme Court affirmed the sentence, with three justices dissenting. Davis I. Mr. Davis then filed a motion for post-conviction relief, arguing that Mr. Truman provided ineffective assistance of counsel during the penalty phase of the trial. Mr. Davis sought additional time to investigate this claim of ineffectiveness. The court conducted a hearing, after which it denied his ineffectiveness claim. The Colorado Court of Appeals affirmed, with one judge dissenting, Davis II, and the Colorado Supreme Court affirmed. Davis III. After exhausting state remedies, Mr. Davis brought this federal habeas petition arguing: (1) Mr. Truman rendered ineffective assistance of counsel during the penalty phase because he (a) abandoned Mr. Davis in his closing argument; and (b) failed to conduct adequate investigation into, and failed to present, mitigating evidence in Mr. Davis’s background; (2) the jury was permitted to consider unconstitutional statutory aggrava-tors; (3) various errors occurred in the penalty phase instructions; and (4) the trial court erroneously excluded three prospective jurors because of their stated qualms about the death penalty. The district court denied his habeas petition. Davis v. Executive Director of Dept. of Corrections, 891 F.Supp. 1459 (D.Colo.1995). Mr. Davis appeals. DISCUSSION We review de novo the district court’s legal conclusions in dismissing a petition for a writ of habeas corpus. Harvey v. Shillinger, 76 F.3d 1528, 1532 (10th Cir.1996), cert. denied, — U.S. -, 117 S.Ct. 253, 136 L.Ed.2d 179 (1996). We review the district court’s factual findings for clear error. Edens v. Hannigan, 87 F.3d 1109, 1113-14 (10th Cir.1996). State court factual findings are presumptively correct and are therefore entitled to deference. Medina v. Barnes, 71 F.3d 363, 369 (10th Cir.1995); 28 U.S.C. § 2254(d). I. Effective Assistance of Counsel. A. Abandonment: Mr. Davis first argues that his attorney, Mr. Truman, effectively abandoned him during closing arguments in the penalty phase of his trial, thereby leaving him without counsel at all. The obligation to provide effective - assistance of counsel extends to a capital sentencing hearing. Brecheen v. Reynolds, 41 F.3d 1343, 1365 (10th Cir.1994), cert. denied, - U.S. -, 115 S.Ct. 2564, 132 L.Ed.2d 817 (1995). “A defense attorney who abandons his duty of loyalty to his client and effectively joins the state in an effort to attain a conviction or death sentence suffers from an obvious conflict of interest,” and thereby fails to provide effective assistance. Osborn v. Shillinger, 861 F.2d 612, 629 (10th Cir.1988). Usually, when a defendant claims ineffective assistance of counsel because his attorney’s performance was inadequate, he must show both constitutionally deficient performance and that he was prejudiced by his attorney’s errors. Brecheen, 41 F.3d at 1865. In the event of an actual conflict of interest occasioned by abandonment, prejudice is presumed. Osborn, 861 F.2d at 626; see also United States v. Williamson, 53 F.3d 1500, 1510-11 (10th Cir.), cert. denied, — U.S. -, 116 S.Ct. 218, 133 L.Ed.2d 149 (1995); Brecheen, 41 F.3d at 1364 n. 17. Mr. Truman began his closing argument in the penalty phase with the following: Now it’s my turn to come and ask you for Gary Davis’s life. That’s what I’m here to do. For 14 long years I have practiced law in these criminal courts and up and down these mean halls. You think you have seen just about everything. You think you have seen everything once. I have never seen a case like this. I never have, and I hopefully never will. R. Vol. V, Vol. 33 at 51. He went on to state: There are times in this case that I hate Gary Davis, I am going to tell you that, and I think you know it. There are times I hate the things that he has done, and I have told him, and I tell you, there’s no excuse for it. There’s no excuse for it whatsoever. In the times that we have seen these cases come and go, they get worse and worse instead of better, and I’m not kidding anybody, this is one of the worst'ones I have ever seen or heard of. I can’t recall a case where I have never made a closing argument, and I can’t recall a case where •we have spoken as little to you as we have this one, and there’s a reason for it. That reason is that in December, when I first saw Gary Davis, I knew that sometime or other I was going to be standing here asking for 12 people’s mercy. That’s all he has got. That’s all we can seek_ I, too, think killing is wrong, and it’s killing, whether it’s the state, and it’s killing, whether it’s Gary Davis.... It says, “Thou shalt not kill,” and if I or you ... or anybody who was there, and if Ginny May would have lived — she didn’t, she died— and if I thought — if I thought that Brandon and Krista May would have five seconds of peace by Gary Davis’s death, I would choke the life out of him right now, and he knows it, but it won’t help.... Some of the’ times I hate Gary Davis is because of what he has done to me. I have been on this case since December, when the public defender got off. The public defender got off because of Gary Davis’s lies, and Gary Davis has lied to me. Gary Davis set up the public defender for failure. In a lot of respects he set me up for failure. I guess I’m too prideful, worried about my reputation. Maybe that’s why I hated him the other day. Id. at 51-53. Mr. Truman then discussed at some length the relationship between Mr. Davis and Ms. Fincham, reiterating the theme of the guili/innocence phase of the trial, that Ms. Fincham was the more culpable of the two. Mr. Truman told the jury: As bad as Gary Davis is — and you won’t hear me say otherwise — -there’s someone equally as bad, maybe worse. That someone continues to lie.... Anything to save Becky Davis [Fincham], That demonstration alone, of watching him testify, I submit to you shows who’s wearing the pants in this family. I’m not saying that forgives Gary Davis. Nothing forgives Gary Davis. He deserves to get what she got. Sauce for the goose is sauce for the gander. They’re in the same position, I submit to you, and I submit to you that both ought either to look at the gas chamber, or both ought to spend the rest of their lives in the penitentiary. Id. at 55. He concluded with the following: I have never had a case like this before, and I have never been able' not to talk to juries, as I almost wasn’t able to talk to you at the start. I guess I’m a prideful man. I have been doing this a long time and I think I’m good at it, and I haven’t said anything during this trial and I have watched you, some of you looking at me, wondering, when are you going to get started? When are you- going to start representing your client? When are you going to get up? I have seen that in your eyes. I know what you mean. You can’t change what’s happened and I am not going to twist or fudge anything for you. Now’s the time for me to be heard. Now’s the time I’m talking to you, and each one of you has it in your hand to spare Gary Davis or to kill him, for if one of you says no, stop the killing, there’s been too much, that’s the way it will be. And if all of-you believe that the only thing for Gary Davis is to put him in the gas chamber, drop those pellets into the cyanide bath, watch him choke to death, that’s what will happen. Is there a man so bad that he’s irredeemable? That’s the question here. There’s no question about what happened. It’s a question about what’s going to happen. I have never begged a jury before for anything, but I’m begging you now, and I am asking you please not to kill Gary Davis. Id. at 56. Mr. Davis relies heavily on our decision in Osborn, calling this case “virtually indistinguishable” from Osborn, in which we held that the defendant’s attorney at the sentencing hearing “so abandoned” his duty to advocate on behalf of his client “that the state proceedings were almost totally non-adversarial.” Osborn, 861 F.2d at 628. Among the statements and actions upon which we based that conclusion were the following: “Osborn’s counsel made statements to the press indicating that Osborn had no evidence to support his claims” and “although counsel knew or should have known that the prosecutor’s office had conveyed ex parte information to the sentencing court, counsel never sought to discover its contents or counteract its effect.” Id. Moreover, the district court described the attorney’s arguments at the sentencing phase as follows: Counsel’s arguments at the sentencing hearing stressed the brutality of the crimes and the difficulty his client had presented to him. At the beginning of the hearing, counsel referred to the difficulty of presenting mitigating circumstances when evidence against a client is overwhelming. In closing, counsel referred to the problems Osborn’s behavior had created for counsel throughout the representation. Counsel described the crimes as horrendous. He analogized his client and the co-defendants to “sharks feeding in the ocean in a frenzy; something that’s just animal in all aspects.” Id. (quoting Osborn v. Schillinger, 639 F.Supp. 610, 617 (D.Wyo.1986), aff'd, 861 F.2d 612 (10th Cir.1988)). We concluded that Osborn’s attorney did more than “make poor strategic choices;” rather, “he acted with reckless disregard for his client’s best interests and, at times, apparently with the intention to weaken his client’s case.” Id. at 629. In our view, Mr. Truman’s closing argument did not constitute abandonment of Mr. Davis, such that the adversarial process was undermined. As the district court observéd, Mr. Truman was placed in a very difficult position because of Mr. Davis’s own decision, against Mr. Truman’s advice, to testify at the end of the guilt/innocenee phase of the trial and take full responsibility for the crime, contrary to the strategy, pursued up to that point, of portraying Mr. Davis as less culpable than Ms. Fineham. That testimony made it even more difficult to explain why Mr. Davis did not deserve the death penalty, while maintaining credibility with the jury. Moreover, while Mr. Truman expressed in general terms how horrible the ease was— “one of the worst ones I have ever seen”— and expressed his hatred of Mr. Davis and his crimes, that is significantly different from “stress[ing] the brutality of the crimes .... describing] the crimes as horrendous ... [and] analogizing] his client and the code-fendants to ‘sharks feeding in the ocean in a frenzy; something that’s just animal in all aspects.’ ” Osborn, 861 F.2d at 628 (quoting Osborn, 639 F.Supp. at 617). Mr. Davis has never disputed that he participated in a crime which was undeniably horrific. Mr. Truman’s statements about Mr. Davis’s lies, to him and to others, while blunt and unflattering to Mr. Davis, were in part a response to Mr. Davis’s decision to testify. His testimony itself, which completely undermined the strategy pursued by Mr. Truman, with Mr. Davis’s apparent approval, revealed the obvious: that Mr. Davis had been at least deceptive towards Mr. Truman. Mr. Truman’s remarks were at least an attempt to cast doubt on the veracity of Mr. Davis, who had just testified in a manner virtually guaranteed to condemn him to a sentence of death. Furthermore, a substantial portion of the closing argument was devoted to stressing the deceptiveness of Ms. Fineham and her control over Mr. Davis, and suggesting that Mr. Davis’s testimony accepting full responsibility for the crime was yet another example of that control. Mr. Truman emphasized that Mr. Davis should receive the same sentence as Ms. Fineham, who had been sentenced to life imprisonment. This was a reiteration of the “equal justice” defense pursued throughout the trial, but substantially undermined by Mr. Davis’s testimony. That had always been the most viable strategy for Mr. Davis to avoid the death penalty, and Mr. Truman effectively pursued it again in closing argument. Finally, Mr. Truman closed his argument with a plea for Mr. Davis’s life': “I have never begged a jury before for anything, but I’m begging you now, and I am asking you please not to kill Gary Davis.” R. Vol. V, Vol. 33 at 56. That was a powerful plea, coming from a man who had just expressed his own dislike of Mr. Davis and his crime. In sum, this case is distinguishable from. Osborn, both because the actual, closing, argument in this case was qualitatively different and because the circumstances of this case left Mr. Truman with little room to maneuver. We therefore hold that Mr. Davis was not abandoned by Mr. Truman in his closing argument. B. Presentation of Mitigating Evidence: Mr. Davis also argues that Mr. Truman was ineffective in failing to adequately investigate potential evidence in mitigation and in failing to present certain mitigating evidence which was available. To establish ineffective assistance of counsel, a defendant “must first show that counsel ‘committed serious errors in light of “prevailing professional norms” ’ in that the representation fell below an objective standard of reasonableness.” Brecheen, 41 F.3d at 1365. See Strickland v. Washington, 466 U.S. 668, 688, 104 S.Ct. 2052, 2064-65, 80 L.Ed.2d 674 (1984). There is a “strong presumption” that counsel has acted reasonably and represented his client effectively. Id. at 689, 104 S.Ct. at 2065. We review an attorney’s performance with substantial deference. Id.; see also Brecheen, 41 F.3d at 1365; Stafford v. Saffle, 34 F.3d 1557, 1562 (10th Cir.1994), cert. denied, — U.S. -, 115 S.Ct. 1830, 131 L.Ed.2d 751 (1995). Once a defendant has shown constitutionally deficient performance, he must demonstrate prejudice from that performance. The defendant bears the burden of proving both deficient performance and prejudice. Brecheen, 41 F.3d at 1365. We review an ineffectiveness ejaim de novo, as it presents a mixed question of law and fact. Brewer v. Reynolds, 51 F.3d 1519, 1523 (10th Cir.1995), cert. denied, — U.S. -, 116 S.Ct. 936, 133 L.Ed.2d 862 (1996). We review the district court’s factual findings for clear error. Id. In some cases, we proceed directly to the issue of prejudice: “[t]he Supreme Court has observed that often it may be easier to dispose of an ineffectiveness claim for lack of prejudice than to determine whether the alleged errors were legally deficient.” United States v. Haddock, 12 F.3d 950, 955 (10th Cir.1993); see also Strickland, 466 U.S. at 697, 104 S.Ct. at 2069-70; Brewer, 51 F.3d at 1523; United States v. Smith, 10 F.3d 724, 728 (10th Cir.1993). This is such a ease. We accordingly express no opinion on whether Mr. Truman’s performance was deficient. To establish prejudice under Strickland, Mr. Davis must show there exists “a reasonable probability that, but for counsel’s unprofessional errors, the result of the proceeding would have been different. A reasonable probability is a probability sufficient to undermine confidence in the outcome.” Strickland, 466 U.S. at 694, 104 S.Ct. at 2068; Brewer, 51 F.3d at 1523. As applied to the penalty phase of a capital case, a petitioner alleging prejudice from counsel’s ineffectiveness must show “a reasonable probability that, absent the errors, the sentencer — including an appellate court, to the extent it independently reweighs the evidence — would have concluded that the balance of aggravating and mitigating circumstances did not warrant death.” Strickland, 466 U.S. at 695, 104 S.Ct. at 2069. We must “keep in mind the strength of the government’s ease and the aggravating factors the jury found as well as the mitigating factors that might have been presented.” Stafford, 34 F.3d at 1564; see also Brewer, 51 F.3d at 1523. Mr. Davis’s specific allegations of error are that Mr. Truman: (1) failed to contact to solicit information and possible testimony from family members, including Tonya Ta-tem, Mr. Davis’s first wife; Glenn Davis, a stepbrother; Adeline Davis, Mr. Davis’s mother; and Mr. Davis’s children and stepchildren; (2) failed to follow up and pursue initial cursory contacts with Mr. Davis’s brother, Wayne Gehrer, and with Mr. Davis’s second wife, Leona Coates; (3) failed to adequately investigate and present expert testimony on Mr. Davis’s alcoholism; (4) failed to explore Ms. Fincham’s psyche, personality and background, including contacting her first husband, Charles, Ledbetter, and presenting expert testimony from Dr. Chris Hatcher, a psychologist who was an expert on relative accomplice liability; (5) failed to contact and adequately develop possible testimony from former employers and acquaintances, including people who lived in the same apartment complex as the Davises; and (6) failed to present favorable prison records from which mitigating evidence might have been derived. Mr. Davis argues that, had the jury heard all of this evidence, it would have viewed him in a different light and probably sentenced him to life imprisonment rather than death. 1. Family Members: Mr. Davis argues Mr. Truman failed to follow up on initial contacts with Mr. Davis’s brother, Wayne Gehrer, and with Mr. Davis’s second wife, Leona Coates, as well as failing to contact at all his first wife, Tonya Tatem, his children and stepchildren, his stepbrother, and his mother. Investigator William Martinez had prepared a report for Mr. Truman’s office, detailing his investigation, conducted in July 1986, into Mr. Davis’s background. It includes a description of a conversation with Wayne Gehrer, in which Mr. Gehrer described Mr. Davis as “always a little bit different, devil-may-care type attitude, always had an alcohol problem.” R. Vol. II, Doe. 54, tab 20. Mr. Martinez’s report indicates “[w]hen asked how he felt about the homicide and about Gary and what he thought of it, his (almost quote) words were — it was the inevitable conclusion to his life’s story.” Id. That assessment of Mr.. Davis was not likely to be viewed by the jury as mitigatory; rather, it suggests he was a reckless and irresponsible man, whose life story was appropriately concluded by the tragic murder of Ms. May. Further discussion with Mr. Gehrer was likely to produce evidence at least as damaging, perhaps more so, than helpful to Mr. Davis. Mr. Davis thus suffered no prejudice from Mr. Truman’s failure to call Wayne Gehrer to testify in the penalty phase of the trial. Mr. Davis similarly challenges Mr. Truman’s failure to pursue Leona Coates as a possible mitigation witness. At the time of Mr. Davis’s trial, she had been interviewed by another investigator, Sherry Gamer, to whom Ms. Coates stated that Mr. Davis had a drinking problem and that there “were times that he was violent with [her.]” Statement of Leona Coates dated 8/7/86, R. Vol. VI. Additionally, she stated that Mr. Davis pointed a rifle at her head one time, and tried to choke her twice. Id. When she testified, nine years later, in Mr. Davis’s habeas proceeding; she stated that Mr. Davis was never violent towards her, that the gun to which she referred in 1986 was a plastic gun, and that she was “under a lot of pressure” in 1986 when she gave the statement about the gun being held to her head. R. Vol. X at 88. The district court described that testimony as “equivocal and contradictory with previous statements given to the police at the time of Davis’ arrest.” Davis, 891 F.Supp. at 1468. The court further observed that Ms. Coates was “not clear that she would have made herself available to testify at the trial because she had moved out of state in order to protect her children from the publicity.” Id. Given the damaging nature of her statements about Mr. Davis in 1986, as well as the uncertainty as to whether she would even have been, available to testify, we see no prejudice to Mr. Davis from Mr. Truman’s failure to call her as a mitigation witness. Mr. Davis also argues he suffered prejudice from the failure to procure testimony from Tonya Tatem, his children and stepchildren, his mother, and a stepbrother. He argues they would have testified about his troubled childhood, his passivity and tendency to be a follower, his devotion to his children, and his recurrent problems with aleo-hol. The district court responded to this argument as follows: “[presenting testimony from.- family, friends, or other associates could have invited inquiry by the prosecution into Davis’ history of violence towards his former wives, his vengeful motives behind the sexual assault of an adolescent girl, his general dishonesty and his sexual exploita-tiveness.” Davis, 891 F.Supp. at 1467. For the following reasons, we agree with the district court that .such testimony was as likely to open the door to damaging evidence as it was to helpful evidence. Tonya Tatem’s affidavit and deposition testimony both described Mr. Davis as a loving and good husband, when he was not drinking. Both also described him as increasingly abusive when drinking. Again, the potentially positive effect of such testimony on the jury is offset by the potentially negative effect of a description of a man who routinely became abusive towards his spouse when drinking, and whose drinking ultimately destroyed their marriage. Various of Mr. Davis’s children and stepchildren testified, either at the habeas hearing or by way of affidavit. Their testimony recalled vague general childhood memories of Mr. Davis as a loving father, as well as more detailed accounts of how he has reestablished his relationship with them since his imprisonment for the murder of Ms. May, and how he is currently helping them. The district court described the direct testimony of three of Mr. Davis’s children as follows: Davis’ three children would have had very little to offer at the trial. Although they each testified as to how important Davis was to them now, they could offer little testimony about the kind of father he had been. Davis spent four of the five years prior to the murder of Virginia May in prison. He did not see his children between the time he was released from prison-and he was arrested for the murder. The only “fatherly” story that each child was able to relate was a well rehearsed anecdote about a family 'fishing trip which probably occurred before the two youngest children would have had any conscious memories. Id. at 1468. We agree with the district court’s characterization of that testimony, noting that the district court, not we, was in the position to evaluate the credibility of those witnesses. Their testimony about Mr. Davis, both at the hearing and by way of affidavit, concerning his character prior to and at the time of the murder was, of necessity, vague and non-specific, simply because they were either fairly young and/or Mr. Davis had spent little time with them. Their testimony about their relationship with him now, and since his conviction and sentence for the May murder, is less significant. We conclude that such testimony would have had very little impact on the jury in this case. Finally, Mr. Davis argues that Mr. Truman should have presented testimony from Glenn Davis, the stepbrother to whom Mr. Davis was closest, as well as from Mr. Davis’s mother. Glenn Davis’s deposition portrays Mr. Davis as a passive follower, but concedes that, if drunk, he might be capable of committing a crime like the murder of Ms. May: “I will say that for him to do that he had to be drunk.... [I]f he was sober and wasn’t drinking that night, in my belief I don’t think Gary would have gone along with it.” Glenn Davis Dep. at 24, R. Vol. IX. Mr. Davis’s mother, Adeline Davis, was not contacted for possible testimony at the time of Mr. Davis’s trial, partially because Wayne Gehrer told Investigator Martinez that Mr. Davis’s parents were experiencing poor health, and he worried that contacting them to testify on their son’s behalf might worsen their health. Adeline Davis’s deposition confirms that she was experiencing severe health problems in 1986 and 1987. Additionally, Mr. Truman testified, at the hearing on the Rule 35(e) motion, that he was aware that after Mr. Davis’s conviction and imprisonment for first-degree sexual assault of the 15-year-old, “his mother indicated that he was no longer welcome at their home and that he was an embarrassment to the family.” R. Vol. IV, Vol. 40 at 50. In sum, we agree with the district court that a decision to present mitigation testimony from family members was fraught with peril, because Mr. Davis’s background contained numerous instances of conduct that was more likely to make a jury feel unsympathetic towards him, than sympathetic towards him. See Brewer, 51 F.3d at 1527 (“[W]hile testimony from a family member may generally be beneficial to a capital defendant at sentencing, we believe that, in-this case, the totality of [the family member’s] revelations could have been devastating.”). The Colorado Supreme Court correctly concluded that “[t]he testimony of such witnesses, if presented, would have constituted, in Truman’s own words, ‘a two-edged sword’ at best.” Davis III, 871 P.2d at 774. We therefore conclude that he suffered no prejudice from the failure to present such testimony. ' 2. Expert Testimony: Mr. Davis also argues that he was prejudiced by the failure to investigate and present expert testimony on the nature and effects of Mr. Davis’s severe alcoholism, as well as on the relationship between Mr. Davis and Ms. Fincham. At the time of the trial, Mr. Truman sought the assistance of a psychiatrist, Dr. Seymour Z. Sundell. After examining Mr. Davis, Dr. Sundell concluded that Mr. Davis’s history and background, including his history of alcoholism, were not useful in mitigation. Mr. Davis introduced in his federal habeas proceeding reports by Dr. Gary Forrest, an expert on the effects of alcoholism, and by Dr. Chris Hatcher, an expert on relative accomplice liability. He claims comparable reports should have been submitted in the penalty phase of his trial, and that the failure to do so prejudiced him. Dr. Forrest’s report described Mr. Davis as “clearly a chronic alcoholic with a concurrent personality disorder” and further opined that “it is highly probable that Mr. Davis was both intoxicated and mentally impaired when Virginia May was murdered.” Pet’r’s Ex. No. Ill, Appel-lee’s Addendum. Aside from the fact that the report itself contains some descriptions of Mr. Davis that might not evoke sympathy at all from a jury, the mitigatory thrust of Dr. Forrest’s report — that Mr. Davis was both intoxicated and mentally impaired when Ms. May was murdered — was undermined by the fact that there was no actual evidence of intoxication when the Davises were first stopped by police on the road, following the murder, as well as by Mr. Davis’s own testimony in which he specifically recalled the murder and his involvement in it. Moreover, the jury already knew that Mr. Davis had a drinking problem, and that he had been drinking the day of the murder. Thus, Dr. Forrest’s conclusions in his report would have either been unsupported by direct evidence at the time of the murder, or would have been duplicative of other evidence already before the jury. Mr. Davis further argues that, besides Dr. Forrest’s expert report and testimony, Mr. Truman should have more generally explored Mr. Davis’s alcoholism as a mitigating circumstance. Mr. Truman testified in the Rule 35(c) proceeding that one reason he declined to explore alcoholism as a mitigator is because the jury might have reacted negatively to the fact that Mr. Davis had been treated numerous times for alcoholism. See Jones v. Page, 76 F.3d 831, 846 (7th Cir.1996) (noting that failure to introduce evidence of petitioner’s long history of substance abuse “was a reasonable tactical choice because such evidence was a ‘double-edged sword,’ that is, it could easily have been considered either aggravating or mitigating evidence”), petition for cert. filed, (U.S. June 28, 1996) (No. 96-5064). We agree that it is just as likely the jury would react negatively to Mr. Davis’s repeated failures to effectively address his alcoholism. Similarly, Dr. Hatcher’s report examines in considerable detail the history of the relationship between Mr. Davis and Ms. Finc-ham. He draws the conclusion that the evidence leads to “serious questions as to who was the dominant individual in the commission of this abduction/homicide.” Pet’r’s Ex. No. 112, Appellee’s Addendum. ■ However, any implication or persuasive suggestion that Ms. Fincham was the dominant actor in the crime was wholly undermined by Mr. Davis’s own statement that he was the main actor and that Ms. Fincham was much less culpable. Even if Dr. Hatcher’s report permits the inference that Mr. Davis was simply lying when he testified against himself, the jury was nonetheless confronted with that clear testimony, under oath, in which Mr. Davis recounted the crime in a manner completely contrary to the way Dr. Hatcher’s report suggests the crime occurred. It is important to note that the jury was able to evaluate Mr. Davis’s credibility and demean- or when he testified, as we, an appellate court, cannot. They were further able to evaluate his credibility in context — that is, having observed him sitting in the courtroom throughout the duration of his trial. We therefore cannot conclude that there is a reasonable probability that, were those two expert reports presented to the jury, the jury would have concluded that death was not the appropriate sentence. 3. Other Acquaintances: Mr. Davis also asserts he suffered prejudice from Mr. Truman’s failure to call other mitigation witnesses, such as people who lived for awhile in the same apartment building as the Davises, and the Davises’ employer. Such evidence was, however, either as likely to harm as help Mr. Davis in front of the jury, or was also directed at showing that Ms. Fincham was the dominant figure in the Davis relationship, and by implication the dominant figure in the murder, a proposition which Mr. Davis’s own testimony effectively rebutted. Among the items of testimony Mr. Davis now claims should have been presented was testimony from Clint and Victoria Hart, who at one time lived in the same apartment as the Davises. In an interoffice memorandum prepared for Mr. Davis’s first attorneys, public defenders, an investigator reported a conversation he had with the Harts, in which they said the following things about the Davises: “.... [T]hey [the Davises] were ripping everybody off, they would borrow money and never paid it back, they were charging for services at the apartments giving receipts for the services and pocketing the money then blaming the owner for having to charge for the services. ... Gary drank a lot and ... they were swingers and tried to get people to swap partners and even jokingly approached them about doing it.... ... [B]oth Gary and Becky were bull shitters but Becky seemed to have the upper hand on that and ... they both lied consistently about everything.... ... Becky acted like she was [in charge] but Gary was the one that really was, he was more subdued where as Becky was talkative and would just rattle on especially when she was lieing [sic].” Interoffice Mem. dated 9/10/86, Appellee’s Addendum. Such negative information about the Davises was obviously more likely to harm rather than help Mr. Davis in front of the jury, and certainly suggested that finding truly helpful mitigating testimony from acquaintances was going to be extremely difficult. We therefore see no prejudice from Mr.-Truman’s decision not to present testimony from the Harts. Mr. Davis also argues Mr. Truman should have presented testimony from Robert Russell, an acquaintance of Mr. Davis and Leona Coates. In a memorandum prepared for Mr. Davis’s first attorneys, - Investigator Jim Smith described an interview with Mr. Russell, in which Mr. Russell generally described how he and Mr. Davis used to go drinking together, and stated that Mr. Davis was not unfaithful to Leona Coates during their marriage. Mr. Russell also said he was “surprised” to hear of Mr. Davis’s involvement in the murder. Interoffice Mem. dated 10/9/86, R. Vol. VI. In another memorandum prepared in connection with Mr. Davis’s habeas petition, Mr. Russell described Mr. Davis as a good, kind and dependable father and worker, without “a mean bone in his body.” Pet’r’s Ex. No. 107,. R. Vol. IX. He further offered his opinion that “the murder had to do with alcohol and someone else’s influence.” Id. We again see no prejudice to Mr. Davis from the failure to present testimony from Mr. Russell, given its generality and vagueness in 1986 (merely expressing “surprise” about Mr. Davis’s involvement in the murder). Even as elaborated nine years later, Mr. Russell’s characterization of Mr. Davis as lacking “a mean bone in his body” is flatly inconsistent with a multitude of other evidence about Mr. Davis, and the reference to alcohol does little to help Mr. Davis other than to raise once again all of the problems discussed above with using alcoholism as a mitigating circumstance in Mr. Davis’s particular case. Finally, Mr. Davis argues he suffered prejudice from the failure to present testimony from Pauline Cowell, the woman for whom the Davises worked at the time of the May murder. In the same memorandum prepared in 1986 by Investigator Jim Smith, Mr. Smith described an interview with Ms. Cowell, in which she said that Mr. Davis “was usually very shy around her,” and that she “does not believe that Gary killed Ginny [May], she is not sure what role he played in it but she does not believe he did it.” Interoffice Mem. dated 10/9/86, R. Vol. VI. She also said that “the stories they, especially Becky told, turned out to be half truths or out right lies.” Id. As with the other acquaintance testimony, it is hard to see how this would have made any difference with the jury. Ms. Cowell said she did not believe Mr. Davis killed Ms. May, but her otherwise unsupported belief was completely contra-dieted by'Mr. Davis’s own testimony. Ms. Cowell also offered that both the Davises told “half truths or out right lies.” That is hardly likely to positively impact the jury deliberating Mr. Davis’s fate. In sum, we find no prejudice from the failure to call these various acquaintances of Mr. Davis to testify in the penalty phase of the trial. 4. Prison Records: Mr. Davis, also argues that Mr. Truman should have presented more testimony supportive of the statutory mitigator that Mr. Davis would not be a continuing threat to society. Mr. Truman did present testimony in the penalty phase from Lieutenant Allen, who had supervised Mr. Davis while he was in the Adams County jail awaiting trial, and who testified to his good conduct during his incarceration. Mr. Davis argues a better witness concerning his conduct while in prison would have been Leonard Foster, who supervised Mr. Davis while he was in prison for his prior sexual assault conviction. Mr. Foster told an investigator' from the Federal Public Defender’s office that Mr. Davis was a model prisoner during that time. He further stated that, had he been asked to testify' at the time of Mr. Davis’s trial, he would have stated his opinion that “Gary Davis could successfully serve a term of life imprisonment.” Sholl Aff. ¶ 11, Pet’r’s Ex. No. 109, R. Yol. IX. Although Mr. Davis for some reason now believes that Mr. Foster would have provided the better testimony in mitigation, Mr. Foster’s testimony basically duplicates that of Lieutenant Allen. Thus, Mr. Davis’s conduct while incarcerated was already before the jury. The failure to present Mr: Foster to provide essentially the same testimony did not prejudice Mr. Davis. Moreover, additional testimony as to Mr. Davis’s ability to function well and adjust comfortably to prison life might have negatively affected jurors who wished to see that Mr. Davis received a severe penalty for an admittedly horrible crime. Details from Mr. Davis’s prison records would also, of course, have reminded the jury of Mr. Davis’s criminal history, with its increasingly violent behavior. Furthermore, against all of this evidence which Mr. Davis presented in the federal district court, and which he claims Mr. Truman erroneously failed to present in the penalty phase of his trial, we must weigh the aggravating factors present in this case. Although Mr. Davis challenges five of the six aggravating factors found by the jury, as we explain below, we find four of the five were constitutional and supported by the evidence, and the submission of the unconstitutionally vague aggravator was harmless error. As we have stated before, the sentence in this case was not “ ‘only weahly supported by the record.’ ” Brewer, 51 F.3d at 1527 (quoting Strickland, 466 U.S. at 696, 104 S.Ct. at 2069). Indeed, Mr. Davis’s own words, detailing his participation in the crime and his assumption of full responsibility for it, were fresh in the jurors’ minds. See Thompson v. Calderon, 86 F.3d 1509, 1525 (9th Cir.1996) (“The State’s case against [petitioner] was strong.... [Petitioner] himself made it much stronger by testifying after counsel advised him not to testify.”). As we stated in Brewer: Given the State’s overwhelming case against him, the number and gravity of the aggravating circumstances found by the jury, and the nature of the crime itself, we do not believe that the speculative, conclu-sory, and possibly damaging mitigating evidence offered now ... would have resulted in the imposition of a sentence other than death. Brewer, 51 F.3d at 1527. We are equally confident that the speculative, cumulative and almost certainly damaging evidence offered now in this case would not have resulted in the imposition of a different sentence. See Marek v. Singletary, 62 F.3d 1295, 1300-01 (11th Cir.1995) (“Given the particular circumstances of this case and the overwhelming evidence against Marek, evidence of an abusive and difficult childhood would have been entitled to little, if any, mitigating weight.”), cert. denied, — U.S. -, 117 S.Ct. 113, 136 L.Ed.2d 65 (1996); Bonin v. Calderon, 59 F.3d 815, 836 (9th Cir.1995) (“ ‘[I]n cases with overwhelming evidence of guilt, it is especially difficult to show prejudice from a claimed error on the part of trial counsel.’”) (quoting United States v. Coleman, 707 F.2d 374, 378 (9th Cir.), cert. denied, 464 U.S. 854, 104 S.Ct. 171, 78 L.Ed.2d 154 (1983)), cert. denied - U.S. -, 116 S.Ct. 718, 133 L.Ed.2d 671 (1996); Andrews v. Collins, 21 F.3d 612, 624 (5th Cir.1994) (holding that in light of evidence that defendant stood over victim and shot him directly in forehead with a bullet altered to cause more devastation on impact, defendant suffered no prejudice from counsel’s alleged ineffectiveness), cert. denied — U.S. -, 115 S.Ct. 908, 130 L.Ed.2d 790 (1995); People v, Rodriguez, 914 P.2d 230, 296 (Colo.1996) (“Given the brutal circumstances surrounding the murder of [the victim] and the overwhelming evidence of aggravation against [defendant], ... trial counsel’s failure to present the proposed mitigating evidence of child abuse [did not] materially affect[] the imposition of’ the death penalty.). II. Statutory Aggravators. The trial court instructed the jury on six statutory aggravators. The jury found the existence of all six beyond a reasonable doubt. Mr. Davis challenges five of the six. Colorado’s capital sentencing scheme involves four steps. The Colorado Supreme Court has described it as follows: First, the jury must determine if at least one of the statutory aggravating factors exists. §§ 16-ll-103(2)(a)(I), -(6). If the jury does not unanimously agree that the prosecution has proven the existence of at least one statutory aggravator beyond a reasonable doubt, the defendant must be sentenced to life imprisonment. §§ 16 — 11— 103(l)(d), -(2)(b)(I), -(2)(c). Second, if the jury has found that at least one statutory aggravating factor has been proven, the jury must then consider whether any mitigating factors exist. §§ 16-11-103(2)(a)(II), -(5). “There shall be no burden of proof as to proving or disproving mitigating factors,” § 16 — 11—103(l)(d), and the jury need not unanimously agree upon the existence of mitigating factors. Third, the jury must determine whether “sufficient mitigating factors exist which outweigh any aggravating factor or factors found to exist.” § 16 — 11—103(2)(a)(II). Fourth, and finally, if the jury finds that any mitigating factors do not outweigh the proven statutory aggravating factors, it must decide whether the defendant should be sentenced to death or to life imprisonment. § 16 — 11—103 (2) (a) (III). People v. Tenneson, 788 P.2d 786, 789 (Colo.1990) (citations omitted); see also People v. White, 870 P.2d 424, 438 (Colo.), cert. denied, — U.S. -, 115 S.Ct. 127, 130 L.Ed.2d 71 (1994). “The constitutional validity of aggravating factors is a question of law subject to de novo review.” United States v. McCullah, 76 F.3d 1087, 1107 (10th Cir.1996). What happens when an unconstitutional aggravator has been submitted to the sentencer depends, in part, on whether the state sentencing scheme involves weighing of aggravating and mitigating circumstances. In a weighing state, “after a jury has found a defendant guilty of capital murder and found the existence of at least one statutory aggravating factor, it must weigh the aggravating factor or factors against the'mitigating evidence.” Stringer v. Black, 503 U.S. 222, 229, 112 S.Ct. 1130, 1136, 117 L.Ed.2d 367 (1992). By contrast, in a non-weighing state “the jury must find the existence of one aggravating factor before imposing the death penalty, but aggravating factors as such have no specific function in the jury’s decision whether a defendant who has been found to be eligible for the death penalty should receive it under all the circumstances of the case.” Id. at 229-30, 112 S.Ct. at 1136. If an unconstitutional aggravating factor has been submitted to the jury in a weighing state, an appellate court may independently reweigh the aggravating and mitigating factors, omitting the unconstitutional one, and determine if the sentence is nonetheless appropriate. Clemons v. Mississippi 494 U.S. 738, 750, 110 S.Ct. 1441, 1449, 108 L.Ed.2d 725 (1990). Alternatively, the appellate court may conduct a harmless error analysis, determining whether the submission to the jury of the unconstitutional aggravator was harmless. Id. at 752, 110 S.Ct. at 1450. Additionally, the Supreme Court has indicated that “a state appellate court may itself determine whether the evidence' supports the existence of the aggravating circumstance as properly defined,” Walton v. Arizona, 497 U.S. 639, 654, 110 S.Ct. 3047, 3057, 111 L.Ed.2d 511 (1990), and on federal habeas review of such a decision, “the state court’s application of the narrowing construction should be reviewed under the ‘rational factfinder’ standard of Jackson v. Virginia, 443 U.S. 307 [99 S.Ct. 2781, 61 L.Ed.2d 560] (1979).” Richmond v. Lewis, 506 U.S. 40, 47, 113 S.Ct. 528, 534, 121 L.Ed.2d 411 (1992). In a non-weighing state, by contrast, so long as the sentencing body finds at least one valid aggravating factor, the fact that it also finds an invalid aggravating factor does not infect the formal process of deciding whether death is an appropriate penalty. Assuming a determination by the state appellate court that the invalid factor would not have made a difference to the jury’s determination, there is no constitutional violation resulting from the introduction of the invalid factor in an earlier stage of the proceeding. Stringer, 503 U.S. at 232, 112 S.Ct. at 1137; see also Tuggle v. Netherland, — U.S. -, 116 S.Ct. 283, 133 L.Ed.2d 251 (1995); Zant v. Stephens, 462 U.S. 862, 103 S.Ct. 2733, 77 L.Ed.2d 235 (1983); Tuggle v. Netherland, 79 F.3d 1386 (4th Cir.1996) (applying harmless error analysis to Ake v. Oklahoma, 470 U.S. 68, 105 S.Ct. 1087, 84 L.Ed.2d 53 (1985), error in capital sentencing proceeding in a non-weighing state), cert. denied, — U.S. -, 117 S.Ct. 237, 136 L.Ed.2d 166 (1996). Step three of Colorado’s four-step capital sentencing scheme clearly requires weighing of aggravating and mitigating circumstances. Step four, however, “require[s] the jury to make an independent decision whether to impose a sentence of life imprisonment or death where mitigating factors did not outweigh aggravating factors.” People v. District Court, 834 P.2d 181, 185 (Colo.1992); see also People v. Young, 814 P.2d 834, 841 (Colo.1991). It thus is more similar to the sentencing decision made in a non-weighing state. The Supreme Court has not specifically indicated whether the Clemons reweighing/harmless-error analysis or the Zant analysis applies to states having “hybrid” systems like Colorado’s. See Flamer v. Delaware, 68 F.3d 736, 769 (3d Cir.1995) (Lewis, J., dissenting), cert. denied, — U.S. -, 116 S.Ct. 807, 133 L.Ed.2d 754 (1996). Mr. Davis suggests that a harmless error analysis is not possible under Colorado’s capital sentencing scheme, apparently because of the fourth step. While he is not completely clear, we assume his argument is that a harmless-error analysis is unavailable in a non-weighing scheme, and therefore unavailable in Colorado because of that fourth step. We disagree with his characterization of Colorado’s capital sentencing scheme. While the fourth step in the sentencing process does indeed appear to give the jury the opportunity to consider any and all reasons for imposing a sentence of life or death, the third step clearly and specifically requires the jury to weigh aggravating and mitigating factors. The jury does not reach the fourth step unless it has determined that any mitigating factors do not outweigh the proven statutory aggravators. Because weighing thus performs a critical function in the jury’s sentencing scheme, we apply, where appropriate, the Clemons harmless error analysis. We turn now to the specific allegations of error. A. Aggravating Factor of “Avoiding or Preventing Lawful Arrest or Prosecution”: One of the statutory aggravators presented to the jury was the following: The class I felony was committed for the purpose of avoiding or preventing a lawful arrest or prosecution or effecting an escape from custody. This factor shall include the intentional killing of a witness to a criminal offense. Colo.Rev.Stat. § 16-ll-103(6)(k). Mr. Davis objected to the- instruction on the ground that the aggravator should only apply when a witness of a crime is killed to prevent the investigation or prosecution of that other, separate, crime or when a law enforcement officer is killed while attempting to arrest someone. The trial court overruled the objection. To be constitutional, an aggravating circumstance must “not apply to every defendant convicted of a murder; it must apply only to a subclass of defendants convicted of murder.” Tuilaepa v. California, 512 U.S. 967, -, 114 S.Ct. 2630, 2635, 129 L.Ed.2d 750 (1994). “If the sentencer fairly could conclude that an aggravating circumstance applies to every defendant eligible for the death penalty, the circumstance is constitutionally infirm.” Arave v. Creech, 507 U.S. 463, 474, 113 S.Ct. 1534, 1542, 123 L.Ed.2d 188 (1993). Additionally, “the aggravating circumstance may not be unconstitutionally vague.” Tuilaepa, 512 U.S. at -, 114 S.Ct. at 2635. The Colorado Supreme Court agreed with the state’s interpretation of this aggravator, that it “is appropriate if the evidence indicates that a defendant has murdered the victim of a contemporaneously or recently perpetrated offense and the reason for the murder was to prevent the victim from becoming a witness.” Davis I, 794 P.2d at 187. The “antecedent crime must be one whieh is not inherent or necessarily incident to murder such as assault or battery, otherwise every murder would be punished by death.” Id. at 187 n. 22. The Colorado court observed that “[b]y putting the focus on the purpose of the murder, this aggravating factor cannot be said to include all murder victims because they are all potential witnesses.” Id. at 187. Mr. Davis argues this interpretation fails to effectively narrow the class of defendants subject to the death penalty, because all murder victims are thereby prevented from testifying against their murderers. He argues “Mrs. May was not a witness to a criminal offense independent of the murder. Rather, the crimes upon her that she had witnessed were part of the same continuous criminal transaction as the murder.” Appellant’s Opening Br. at 78. We agree with the Colorado Supreme Court, whose analysis the district court adopted, that the statutory aggravator sufficiently narrows the class of defendants to whom it applies. Several other states have a similar statutory aggravating circumstance. Arkansas, for example, includes among its aggravating circumstances that “[t]he capital murder was committed for the purpose of avoiding or preventing an arrest or effecting an escape from custody.” Ark.Code Ann. § 5-4-604(5). The Eighth Circuit recently rejected an argument that the provision “does not genuinely narrow the class of persons eligible for the death penalty.” Wainwright v. Lockhart, 80 F.3d 1226, 1231 (8th Cir.1996), cert. denied, — U.S. -, 117 S.Ct. 395, 136 L.Ed.2d 310 (1996). In Wainwright, the court held that the aggravator was properly applied to a murder which was committed in the course of a robbery, in order to prevent the murderer’s identification by the victim. See also Joubert v. Hopkins, 75 F.3d 1232, 1247 (8th Cir.) (upholding validity of Nebraska statutory aggravator that the killing was committed to hide the perpetrator’s identity where defendant kid-naped victims before killing them), cert. denied, — U.S. -, 116 S.Ct. 2574, 135 L.Ed.2d 1090 (1996); Ruiz v. Norris, 71 F.3d 1404, 1408 (8th Cir.1995), cert. denied, — U.S. -, 117 S.Ct. 384, 136 L.Ed.2d 301 (1996); Miller v. State, 269 Ark. 341, 605 S.W.2d 430, 439-40 (1980) (upholding validity of statutory aggravator that murder was committed for purpose of avoiding arrest where defendant robbed victim before killing him), cery. denied, 450 U.S. 1035, 101 S.Ct. 1750, 68 L.Ed.2d 232 (1981); Thompson v. State, 648 So.2d 692, 695 (Fla.1994) (upholding validity of statutory aggravator that murder was committed for purpose of avoiding arrest where defendant kidnaped and robbed victims before murdering them), cert. denied, — U.S. -, 115 S.Ct. 2283, 132 L.Ed.2d 286 (1995); Walker v. State, 671 So.2d 581, 602 (Miss.1995) (upholding validity of statutory aggravator that murder was committed for purpose of avoiding or preventing a lawful arrest where defendants kid-naped and raped victim before murdering her), petition for cert. filed, (U.S. July 16, 1996) (No. 96-5259); State v. Hightower, 146 N.J. 239, 680 A.2d 649, 663 (1996) (upholding validity of statutory aggravator that murder was committed to avoid apprehension where victim was robbed prior to murder, and observing that “[t]he fact that a murder occurs contemporaneously with the witnessed underlying crime does not mitigate the evil of killing a potential witness”); State v. Gregory, 340 N.C. 365, 459 S.E.2d 638, 664 (1995) (upholding validity of statutory aggravator that murders were committed for the purpose of avoiding or preventing a lawful arrest where defendants had kidnaped and raped victims prior to killing them), cert. denied, — U.S. -, 116 S.Ct. 1327, 134 L.Ed.2d 478 (1996). In each of these cases, the aggravating circumstance was applied where an antecedent crime (rape or kidnap-ing or robbery) occurred, and the murderer killed the victim to prevent the victim’s identification of the murderer for the antecedent crime. That is exactly what occurred in this case: Mr. Davis testified that he killed Ms. May so she would not be a live witness. R. Vol. V, Vol. 32 at 73. Further, the evidence in this ease concerning the Davises’ motivation for murdering Ms. May, which Mr. Davis does not dispute, supports the conclusion that their motivation for kidnaping Ms. May was to subject her to various sexual abuses, and she was then murdered so she would not identify them. We find nothing unconstitutional in the application of this ag-gravator to Mr. Davis. B. Application of the “Party to an Agreement” Aggravator: Mr. Davis also challenges the statutory aggravator that Mr. Davis “has been a party to an agreement to kill another person in furtherance of which a person has been intentionally killed.” Colo.Rev.Stat. § 16 — 11— 103(6)(e). He argues, as he did at his trial, that this aggravator should only apply to contract killings, not to “simple conspiracy.” Appellant’s Opening Br. at 87. As the Supreme Court has stated, “[s]tates must properly establish a threshold below which the [death] penalty cannot be imposed.” Romano v. Oklahoma, 512 U.S. 1, -, 114 S.Ct. 2004, 2009, 129 L.Ed.2d 1 (1994); McCleskey v. Kemp, 481 U.S. 279, 305, 107 S.Ct. 1756, 1774, 95 L.Ed.2d 262 (1987). To that end, they must “establish rational criteria that narrow the decisionmaker’s judgment as to whether the circumstances of a particular defendant’s case meet the threshold.” Id. We have recognized that “aggravating circumstances must be described in terms that are commonly understood, interpreted and applied. To truly provide guidance to a sentencer who must distinguish between murders, an aggravating circumstance must direct the sentencer’s attention to a particular aspect of a killing that justifies the death penalty.” Cartwright v. Maynard, 822 F.2d 1477, 1485 (10th Cir.1987), aff'd, 486 U.S. 356, 108 S.Ct. 1853, 100 L.Ed.2d 372 (1988). An aggravating circumstance cannot be so vague that it fails to effectively channel the sentencer’s discretion, and it must contribute to the kind of individualized sentencing necessary for the imposition of the death penalty. “Beyond these limitations, ... the Court has deferred to the State’s choice of substantive factors relevant to the penalty determination.” California v. Ramos, 463 U.S. 992, 1001, 103 S.Ct. 3446, 3453, 77 L.Ed.2d 1171 (1983). Mr. Davis makes no specific argument why the “party to an agreement” aggravator is not a rational criterion by which Colorado could select those for whom the death penalty is permissible. He simply argues that the Colorado legislature did not intend it to apply other than to contracts for hire, an argument the Colorado Supreme Court rejected, and that no other state includes such an aggravator in its capital sentencing scheme. Neither argument persuades us that habeas relief is necessary. The Colorado Supreme Court examined the legislative history behind the statute, and determined that it was not limited to “contract-murders,” as Mr. Davis argues. Absent some compelling argument that that interpretation violates the federal constitution, we will not disturb it. See Bowser v. Boggs, 20 F.3d 1060, 1065 (10th Cir.) (“We will not second guess a state court’s application dr interpretation of state law on a petition for habeas unless such application or interpretation violates federal law.”), cert. denied, — U.S. -, 115 S.Ct. 313, 130 L.Ed.2d 275 (1994); Hamm v. Latessa, 72 F.3d 947, 954 (1st Cir.1995) (same), cert. denied, — U.S. -, 117 S.Ct. 154, 136 L.Ed.2d 99 (1996); see also Mansfield v. Champion, 992 F.2d 1098, 1100 (10th Cir.1993) (“In a habeas corpus proceeding under section 2254, a federal court should defer to a state court’s interpretation of state law in determining whether an incident constitutes one or more than one offense for double jeopardy purposes.”). And the fact that Colorado may be the only state which permits such an aggravator by itself indicates no constitutional infirmity. As the Supreme Court has made clear, unless the aggravator is unconstitutionally vague on its face, or otherwise impedes the requirement that sentencing determinations be individualized, states are free to select whatever substantive criteria they wish to determine who is eligible for the death penalty. See Spaziano v. Florida, 468 U.S. 447, 464, 104 S.Ct. 3154, 3164, 82 L.Ed.2d 340 (1984) (“The Eighth Amendment is not violated every time a State reaches a conclusion different from a majority of its sisters over how best to administer its criminal laws.”). C. Consideration of the “Especially Heinous, Cruel or Depraved ” Aggra-vator: The jury was also instructed on the aggravating factor that “[t]he defendant committed the offense in an especially heinous, cruel, or depraved manner.” Colo.Rev.Stat. § 16 — 11— 103(6)(j). The trial court offered no elaboration of the language of the statute, and overruled Mr. Davis’s objection to the aggravator as unconstitutionally vague. The United States Supreme Court in Maynard v. Cartwright, 486 U.S. 356, 108 S.Ct. 1853, 100 L.Ed.2d 372 (1988), held that Oklahoma’s “especially heinous, atrocious or cruel” statutory aggravator, if presented to a jury without further elaboration and explication, was unconstitutionally vague. The Colorado Supreme Court