Opinion by Judge TASHIMA; Concurrence by Judge THOMAS; Partial Concurrence and Partial Dissent by Judge O’SCANNLAIN.

Robert Garceau was convicted of a double homicide in California state court and sentenced to death. The California Supreme Court affirmed his conviction and sentence, People v. Garceau, 6 Cal.4th 140 , 24 Cal.Rptr.2d 664 , 862 P.2d 664 (1993), cert. denied, 513 U.S. 848 , 115 S.Ct. 144 , 130 L.Ed.2d 84 (1994), and denied his state habeas petition on the merits. He then filed a habeas petition in federal district court, raising 28 separate grounds for relief. In due course, he moved the district court for an evidentiary hearing on several of these claims. The district court denied his motion for an evidentiary hearing and later denied his petition. Garceau appeals the district court’s denial of an evidentiary hearing on four of his claims, as well as the district court’s denial of his petition on three of his claims. We have jurisdiction over this timely appeal pursuant to 28 U.S.C. § 2253 , and we reverse.

I. FACTUAL BACKGROUND AND PRIOR PROCEEDINGS

Robert Garceau was convicted in Kern County, California, of first degree murder for the September 1984 stabbing deaths 17249 of his girlfriend, Maureen Bautista, and her 14-year-old son, Telesforo Bautis-ta. Their bodies were not found until six months later, in a bedroom dresser buried under a layer of concrete in the backyard of one of Garceau’s drug partners, Greg Rambo. There was no physical evidence linking Garceau to the murders. The State’s case against him consisted largely of the testimony of several persons with whom Garceau manufactured methamphetamine. These drug partners testified that Garceau had confessed to them that he had killed the Bautistas because he was worried that they would reveal his drug activities to law enforcement authorities. They further testified that after Garceau murdered the Bautistas, he returned to the scene of the crime with two of his drug partners and stuffed the Bautistas’ bodies into a bedroom dresser. Garceau and Greg Rambo then transported the dresser to Rambo’s house. They buried the dresser under a layer of concrete in Rambo’s backyard.

A few months later, in February 1985, Greg Rambo was shot to death. Prior to his trial for the Bautista murders, Garceau was charged with and convicted of Greg Rambo’s murder and sentenced to 33 years to life imprisonment. At Garceau’s trial for the Bautista murders, several of his drug partners testified that he had told them that he had killed Rambo as well. After Rambo’s death, his wife, Susan, led *772 the police to the bodies of the Bautistas buried in her backyard.

Virtuaily every single one of the prosecution’s witnesses had some connection to the murder of the Bautistas or some other self-interested reason for testifying against Garceau. Susan Rambo assisted in digging the hole in her backyard in which the dresser containing the Bautistas was buried for six months. She testified under a grant of immunity. Larry Tom Whitting-ton helped stuff the Bautistas’ bodies into the dresser at the crime scene. Patricia Shepard was Whittington’s girlfriend; she and Whittington cleaned up the bloodstains at the crime scene the day after the bodies were removed. Hariyn Codd helped Garceau dispose of Rambo’s body. The only witness that does not appear to have had a hand in any of the three murders was Wayne James. He was, however, involved in illegal drug manufacturing with Garceau, and he did not come forward to the police until a few days before he testified. Garceau argues that weapons charges against James were dropped after he agreed to testify. Garceau’s defense at trial was that one or more of these drug partners killed the Bautistas.

At the sentencing phase, the prosecution presented evidence of Garceau’s prior convictions for burglary and weapons charges. In addition, the jury heard evidence that Garceau possessed high-powered firearms on many other occasions, and that he was involved in a kidnaping. In mitigation, Garceau presented evidence of his history in prison, his upbringing, his character, and his caring relationships with people. The jury fixed the penalty at death.

Garceau appealed his conviction and sentence to the California Supreme Court, which affirmed the conviction and sentence. It also denied his state habeas petition on the merits. Garceau requested the appointment of counsel to pursue his federal habeas remedies and a stay of execution in federal district court on May 12, 1995. Counsel was appointed on June 26, 1995, and Garceau filed his federal habeas petition on July 2,1996. 1

The district court eventually dismissed two of Garceau’s 28 habeas claims for failure to exhaust them in state court proceedings. Garceau next filed a motion for an evidentiary hearing on several of his claims, which was denied. Ultimately, the district court denied his habeas petition, as well as the issuance of a certificate of probable cause. Garceau filed a notice of appeal from the final judgment on August 26, 1999, and we issued a certificate of probable cause on January 21, 2000. 2

*773 II. DISCUSSION

Garceau contends that the district court erred by: (1) denying his request for an evidentiary hearing on his ineffective assistance of counsel and equal protection claims; (2) dismissing his claim that the State used its peremptory challenges in a racially discriminatory manner; (3) dismissing his claim that the “other crimes” jury instruction violated the Due Process Clause; and (4) dismissing his claim that the trial court’s failure to give the jury a “voluntary intoxication” instruction violated the Due Process Clause. Because we conclude that habeas relief is warranted based on the “other crimes” jury instruction, we find it unnecessary to address the remaining issues.

A. Standard of Review

We review de novo the district court’s decision to deny a petition for a writ of habeas corpus. Bribiesca v. Galazo, 215 F.3d 1015, 1018 (9th Cir.2000).

B. The “Other Crimes” Jury Instruction

During Garceau’s trial, the State introduced two types of evidence of other crimes committed by Garceau: evidence that he manufactured illegal drugs and testimonial evidence that, several months after he allegedly murdered the Bautistas, he murdered Greg Rambo (a crime for which he had already been convicted). Although Garceau did not object to this evidence (in fact, he had planned to introduce it himself), he did object to the trial court’s instruction to the jury regarding this evidence, which read as follows:

Garceau, 24 Cal.Rptr.2d 664 , 862 P.2d at 690 n. 17 (emphasis added). Garceau asked instead for a modified version of the standard California (CALJIC) instruction on other crimes evidence, which would have instructed the jury that such evidence “may not be considered by you to prove ... bad character or ... disposition to commit crimes.” Id. at 690 n. 18. His request was rejected by the court.

On direct appeal, Garceau argued that the trial court’s instruction violated California Evidence Code § 1101, which reads:

Cal. Evid.Code § 1101(a), (b) (2001) (emphasis added). The California Supreme Court agreed, holding that the instruction “impermissibly invited the jury to consider certain evidence (e.g., that defendant killed Rambo) for the purpose of establishing defendant’s propensity to commit murder.” Garceau, 862 P.2d at 691 . The California Supreme Court concluded, however, that the error was harmless because there was “overwhelming evidence” of Garceau’s guilt. Id. at 691-92.

Garceau argues that, not only was the instruction contrary to California law, but it violated the Due Process Clause by permitting the jury to use the evidence of his other crimes to establish his criminal propensity, i.e., the likelihood that he committed the charged crimes.

The Supreme Court has held that it is not a violation of due process to admit other crimes evidence, for purposes other than to show conduct in conformity therewith, where the jury is given a limiting instruction “that it should not consider the prior conviction as any evidence of the defendant’s guilt on the charge on which he was being tried.” Spencer v. Texas, 385 U.S. 554, 558, 563-64 (1967); accord Estelle v. McGuire, 502 U.S. 62, 74-75 (1991). The defendant in Spencer was charged with murder and the trial court admitted into evidence the fact that the defendant had previously been convicted of murder. Spencer, 385 U.S. at 557 , 87 S.Ct. 648 . Although the Supreme Court did not explicitly say that the limiting instruction was necessary to the constitutional admission of the other crimes evidence, it relied on the existence of the limiting instruction in holding that there was no due process violation. Id. at 562 , 87 S.Ct. 648 (“This type of prejudicial effect is acknowledged to inhere in criminal practice, but it is justified on the grounds that ... the jury is expected to follow instructions in limiting this evidence to its proper function....”).

This rebanee has led two circuits to hold that the admission of other crimes evidence, for purposes other than to show conduct in conformity therewith, violates due process in the absence of a limiting instruction. See Panzavecchia v. Wainwright, 658 F.2d 337, 341 (5th Cir.1981) (holding that it violated due process for the jury to hear “repeated references to the defendant’s criminal past without any limiting instruction to relate this evidence only to the firearm violation and to disregard it altogether in considering the murder count”); Murray v. Superintendent, Ky. State Penitentiary, 651 F.2d 451, 453 (6th Cir.1981) (noting that the Sixth Circuit has held that “[t]he logical converse of [Spencer] is that it is unfair and violative of due process if evidence of other crimes is admitted without a limiting instruction”).

Nonetheless, the Supreme Court has never expressly held that it violates due process to admit other crimes evidence for the purpose of showing conduct in conformity therewith, or that it violates due process to admit other crimes evidence for other purposes without an instruction bmiting the jury’s consideration of the evidence to such purposes. Indeed, the Supreme Court has expressly declined to answer these questions, see Estelle, 502 U.S. at 75 n. 5, 112 S.Ct. 475 (“Because we need not reach the issue, we express no opinion on whether a state law would *775 violate the Due Process Clause if it permitted the use of ‘prior crimes’ evidence to show propensity to commit a charged crime.”). 3

The Ninth Circuit has addressed the first of the issues left open by the Supreme Court by holding that the admission of other crimes evidence, where there were no permissible inferences the jury could have drawn from the evidence (in other words, no inference other than conduct in conformity therewith), violates due process. See McKinney v. Rees, 993 F.2d 1378, 1384 (9th Cir.1993); Jammal v. Van de Kamp, 926 F.2d 918, 920 (9th Cir.1991). In Jammal and McKinney , however, we did not have before us a case, like this one, where there is a permissible inference that the jury could draw from the other crimes evidence, but where the jury was expressly invited to draw the additional inference of criminal propensity. 4

The question we must answer, therefore, is whether the express propensity instruction in this case “by itself so infected the entire trial that the resulting conviction violates due process.” Estelle, 502 U.S. at 72 , 112 S.Ct. 475 (internal quotation marks and citations omitted). The analysis underlying McKinney supports the conclusion that the jury instruction at issue so offended fundamental conceptions of justice and fair play as to rise to the level of a constitutional violation. Specifically, in McKinney , we held that the admission of other crimes evidence violated due process where: (1) the balance of the prosecution’s case against the defendant was “solely circumstantial;” (2) the other crimes evidence, which involved the defendant’s past use of knives, was similar to the stabbing for which he was on trial; (3) the prosecutor relied on the other crimes evidence at several points during the trial; and (4) the other crimes evidence was “emotionally charged.” McKinney, 993 F.2d at 1381-82, 1385-86 .

Application of the McKinney factors to this ease similarly leads to the conclusion that the other crimes jury instruction violated due process. First, the State’s case, absent the impermissible propensity inference, was not a strong one. There was no physical evidence connecting Garceau to the alleged murders. The State’s case consisted entirely of testimony by Gar-ceau’s drug partners that Garceau had told them that he had committed the murders and circumstantial evidence. Garceau argued to the jury, not implausibly, that this testimony was tainted by self-interest. Second, the impermissible propensity inference in this case was very strong. The other crime, Rambo’s murder, was precisely the same crime for which Garceau was on trial. In addition, the proximity between Rambo’s murder and the murders for which Garceau was on trial was a very close five months. ' Third, the prosecutor relied fairly heavily on the Rambo murder *776 in urging the jury to draw the propensity inference. 5 Fourth, the other crime in this case was explained in graphic detail and very likely emotionally affected the jury.

Moreover, McKinney based its conclusion regarding the Due Process Clause on the fact that “drawing propensity inferences from ‘other acts’ evidence of character is impermissible under an historically grounded rule of Anglo-American jurispru-dence_” Id. at 1384 . The court held that when no other inference is possible, such evidence must be excluded. Id. The harm of “drawing the propensity inference” is no less stark, however, where it is possible for the jury additionally to draw other inferences. The only way to mitigate this harm, short of excluding the evidence altogether (which Spencer and Estelle held is not required by due process) is to give the jury a limiting instruction. Even worse than failing to give such an instruction is what the trial court did in this case: affirmatively inviting the jury to draw the propensity inference. Accordingly, we conclude that the other crimes jury instruction rendered Garceau’s trial so fundamentally unfair as to constitute a violation of the Due Process Clause.

We must next determine whether the due process violation constituted harmless error. The California Supreme Court held the erroneous jury instruction in this case was harmless under the “harmless beyond a reasonable doubt” standard of Chapman v. California, 386 U.S. 18 , 87 S.Ct. 824 , 17 L.Ed.2d 705 (1967). Gar-ceau, 862 P.2d at 691-92 . Although that is the correct standard for direct review, habeas review is more deferential. See Brecht v.

Abrahamson, 507 U.S. 619, 637 , 113 S.Ct. 1710 , 123 L.Ed.2d 353 (1993) (“The imbalance of the costs and benefits of applying the Chapman harmless-error standard on collateral review counsels in favor of applying a less onerous standard on habeas review of constitutional error.”). On habeas review, error is harmless unless it “ ‘had substantial and injurious effect or influence in determining the jury’s verdict.’ ” Id. (quoting Kotteakos v. United States, 328 U.S. 750, 776 , 66 S.Ct. 1239 , 90 L.Ed. 1557 (1946)). That is, the error is harmless unless Garceau can establish “actual prejudice.” Brecht, 507 U.S. at 637 , 113 S.Ct. 1710 (internal quotation marks and citation omitted).

The district court accorded the California Supreme Court’s conclusion that the error in this case was harmless beyond a reasonable doubt a “presumption of correctness” because it was a “state court finding[ ].” As Garceau correctly points out, however, “[wjhether the constitutional error was harmless is not a factual determination entitled to the statutory presumption of correctness under 28 U.S.C. § 2254 (d).” Lawson v. Borg, 60 F.3d 608, 612 (9th Cir.1995). Thus, we consider the harmless error question de novo.

The court in McKinney stated that “[t]he analysis that leads us to conclude *777 that the erroneous admission of propensity evidence rendered [defendant’s] trial fundamentally unfair in violation of the Due Process Clause is similar to the analysis we must undertake to determine whether his conviction must be set aside on collateral review.” McKinney, 993 F.2d at 1385 . The court proceeded to conduct the harmless error analysis by evaluating the same factors it had used to determine that a constitutional violation had occurred. Id. at 1386 . Following McKinney , in order to determine whether the jury instruction in this case constituted harmless error, we therefore examine the quality, significance, and pervasiveness of the evidence related to the propensity instruction.

As discussed above, a review of the record leads to the conclusion that the instruction did not constitute harmless error. The evidence against Garceau was not weighty; in fact, there was no direct physical evidence implicating Garceau and the conviction turned on the testimony of potentially biased witnesses. In addition, the other crimes evidence was used pervasively throughout the trial. Indeed, the prosecutor made significant reference to the Rambo murder during closing argument. Moreover, one of the other crimes in question — Rambo’s murder — was identical to the crime for which Garceau was on trial, heightening its emotional impact and evi-dentiary significance. 6 In light of these facts, it was highly probable that the court’s instruction to the jury to consider Garceau’s other crimes to judge his conduct had a substantial and injurious effect on determining the jury’s verdict. See id.

The State argues, and the California Supreme Court concluded, that the balance of the State’s case against Garceau was “overwhelming.” This argument is based largely on the fact that several people testified in detail that Garceau confessed to them that he had committed the murders. It is true that evidence of a confession carries significant weight on harmless error review, at least when the defendant has confessed to the police. See, e.g., Tucker v. Johnson, 242 F.3d 617, 629 (5th Cir.) (holding that admission of other crimes evidence was harmless in light of defendant’s confession to police and overwhelming evidence of guilt), cert. denied, — U.S. -, 122 S.Ct. 18 , 150 L.Ed.2d 800 (2001). The confessions introduced in this case, however, were not made to the police, but assertedly to drug partners who arguably had reasons to lie. This weakens considerably the evidentiary weight of the confessions and, as a result, significantly undermines the State’s assertion that the weight of the evidence of guilt was overwhelming. When viewed in the context of the entirely circumstantial and self-interested nature of the evidence against Garceau, the fact that the jury was instructed to infer criminal propensity from the other crimes testimony clearly prejudiced Garceau’s case. We conclude, therefore, that the admittedly unconstitutional jury instruction was not harmless and that the writ of habeas corpus should issue.

III. CONCLUSION

For the foregoing reasons, we conclude that the district court erred in denying Garceau’s habeas petition on the ground that the “other crimes” jury instruction, albeit erroneous, was harmless error. Because Garceau’s trial and conviction were infected with constitutional error which *778 had a substantial and harmful effect on the jury’s verdict, we reverse the judgment of the district court denying Garceau’s petition for a writ of habeas corpus. We remand the case to the district court with directions to issue the writ, unless the State grants Garceau a new trial within a reasonable period of time to be set by the district court.

REVERSED and REMANDED.

. Although Garceau's petition for the writ of habeas corpus was filed after the effective date of the Antiterrorism and Effective Death Penalty Act of 1996 (AEDPA), Pub.L. No. 104-132, 110 Stat. 1214, the AEDPA does not generally apply to his petition. This is the case because the AEDPA does not apply to petitions that were “pending” as of the effective date of the AEDPA, Calderon v. United States Dist. Court (Kelly), 163 F.3d 530 , 539 (9th Cir.1998) (en banc), cert. denied, 526 U.S. 1060 , 119 S.Ct. 1377 , 143 L.Ed.2d 535 (1999), and Garceau's petition is considered "pending” as of May 12, 1995, the date he requested both that federal habeas counsel be appointed and that his execution be stayed, id. at 540.

. The provisions of the AEDPA regarding the issuance of a certificate of appealability (COA) as a predicate to review in the court of appeals apply to all cases in which the notice of appeal was filed after the AEDPA’s effective date, April 24, 1996. See Slack v. McDaniel, 529 U.S. 473, 482 , 120 S.Ct. 1595 , 146 L.Ed.2d 542 (2000). Garceau filed his notice of appeal after that date. In these circumstances, we treat Garceau's notice of appeal as an application for a COA. See Whelchel v. Washington, 232 F.3d 1197 , 1202 n. 1 (9th Cir. 2000). Under the AEDPA, a court may issue a COA when "the applicant has made a substantial showing of the denial of a constitutional right.” 28 U.S.C. § 2253 (c)(2). To *773 meet this standard, the petitioner "must demonstrate that the issues are debatable among jurists of reason; that a court could resolve the issues [in a different manner]; or that the questions are adequate to deserve encouragement to proceed further.” Lambright v. Stewart, 220 F.3d 1022, 1025 (9th Cir.2000) (quoting Barefoot v. Estelle, 463 U.S. 880 , 893 n. 4, 103 S.Ct. 3383 , 77 L.Ed.2d 1090 (1983) (internal quotation marks omitted) (emendation in the original)). Because it is clear that Garceau meets this standard, we grant the COA and exercise jurisdiction over all issues presented in this appeal. See Whelchel, 232 F.3d at 1202 n. 1.

. In his partial dissent in Spencer , Chief Justice Warren argued that "[w]hile this Court has never held that the use of prior convictions to show nothing more than a disposition to commit crime would violate the Due Process Clause of the Fourteenth Amendment, our decisions ... suggest that evidence of prior crimes introduced for no purpose other than to show criminal disposition would violate the Due Process Clause.” 385 U.S. at 572-74 , 87 S.Ct. 648 . This comports with the Advisory Committee's analysis of Fed. R. Evid. 404, that the general rule against using other crimes evidence to make inferences about character or propensity in a criminal case "is so deeply imbedded in our jurisprudence as to assume almost constitutional proportions.” Fed.R.Evid. 404(a) advisory committee note (1972).

. In Jammal , there was no limiting instruction, but the defendant was "barred from complaining” about its absence because he did not request one. 926 F.2d at 920 n. 2. Garceau asked for a limiting instruction.

. The prosecutor referred to Rambo's murder on dozens of pages of the transcript of his closing argument. He began his closing argument by saying that he intended to show that "the defendant[was] the killer of not only Maureen Bautista and Telesforo Bautista but Greg Rambo." State Ct. Rep. Tr. at 3658. He tied the murders together at several points in his closing argument, perhaps most extensively by using several pages of transcript to make a point-by-point comparison of the three murders, arguing that "[t]here are certain systems at least of categories that connect Maureen and Telesforo's murder with Greg Rambo's murder.” State Ct. Rep. Tr. at 3861-65. He concluded: "Garceau is the common denominator. Garceau is the one who committed the murders.” State Ct. Rep. Tr. at 3865. 17258

. Nor was the other crimes evidence in this case “cumulative” of properly admitted evidence. See Brecht v. Abrahamson, 507 U.S. 619, 639 , 113 S.Ct. 1710 , 123 L.Ed.2d 353 (1993); see also Laboa v. Calderon, 224 F.3d 972, 978 (9th Cir.2000) (holding improperly admitted confession was harmless because it "added nothing to the evidence”).