Sheriff Don Horsley of San Mateo County, California, appeals from the district court’s order granting Jose Napolean Santamaria’s petition for writ of habeas corpus. The district court had jurisdiction under 28 U.S.C. § 2254. We have jurisdiction over this timely appeal pursuant to 28 U.S.C. §§ 1291 and 2253, and we affirm.
I
In February 1989, a jury found Santamaría guilty of murder and robbery, but found “not true” a sentence enhancement charge, under California Penal Code § 12022(b), that he personally used a deadly weapon in the commission of a felony. See People v. Santamaria, 8 Cal.4th 903, 909, 35 Cal.Rptr.2d 624, 884 P.2d 81 (1994) (Santamaria). A state appellate court reversed the murder conviction, holding that an 11-day continuance during jury deliberations was prejudicial error. Id. at 909, 35 Cal.Rptr.2d 624, 884 P.2d 81, citing People v. Santamaria, 229 Cal.App.3d 269, 280 Cal.Rptr. 43 (1991).
On remand, Santamaría filed a motion to, among other things, “preclude prosecution’s reliance on theory adjudicated in defendant’s favor at first trial.” Id. The trial court granted the motion, ruling that the collateral estoppel component of the Double Jeopardy Clause barred the prosecution “from retrying the defendant on the theory that he personally used the knife during the killing.” Id. The prosecution subsequently stated that it was unable to proceed in light of the court’s ruling, and the case was dismissed. The California Court of Appeal affirmed the trial court’s dismissal of the ease, but the California Supreme Court reversed. That court held “that collateral estoppel does not apply,” id. at 922, 35 Cal.Rptr.2d 624, 884 P.2d 81, and remanded the case to the trial court with instructions to reinstate the charges.
Santamaría then filed this petition for writ of habeas corpus in the United States District Court for the Northern District of California. The district court held that our decision in Pettaway v. Plummer, 943 F.2d 1041 (9th Cir.1991) (Pettaway), cert. denied, 506 U.S. 904, 113 S.Ct. 296, 121 L.Ed.2d 220 (1992), compelled the conclusion that the Double Jeopardy Clause bars the prosecution from arguing at retrial that Santamaría used a knife to commit murder. Therefore, the district court issued the writ. The Sheriff, Santamaría, and the California Supreme Court all agree that this case is factually indistinguishable from Pettaway, and that the only substantial legal issue before us is the continuing vitality of that decision. See Santamaria, 8 Cal.4th at 923, 35 Cal.Rptr.2d 624, 884 P.2d 81 (“People v. Pettaway ... involved virtually the same issue and procedural posture as this case, except that there the weapon enhancement that the jury found not true was for use of a firearm, not a knife.”).
II
We review de novo a district court’s decision to grant or deny a writ of habeas corpus. Martinez-Villareal v. Lewis, 80 F.3d 1301, 1305 (9th Cir.), cert. denied, — U.S. -, 117 S.Ct. 588, 136 L.Ed.2d 517 (1996). The habeas corpus provisions of the Antiterrorism and Effective Death Penalty Act of 1996 (amendments to 28 U.S.C. §§ 2241-2255) do not apply retroactively to this appeal. Jeffries v. Wood, 103 F.3d 827 (9th Cir.1996).
The Sheriff urges us to revisit Pettaway for three reasons: (1) it was decided incorrectly as an original matter; (2) it rested upon an erroneous interpretation of California law since corrected by the California Supreme Court; and (3) it has been undermined by the Supreme Court’s intervening decisions in Caspari v. Bohlen, 510 U.S. 383, 114 S.Ct. 948, 127 L.Ed.2d 236 (1994) (Caspari ), and United States v. Dixon, 509 U.S. 688, 113 S.Ct. 2849, 125 L.Ed.2d 556 (1993) (Dixon). We will address each of the Sheriff’s contentions in turn.
*1355A.
The Sheriffs first ground for urging us to overrule Pettaway cannot be accepted. It is settled law that one three-judge panel of this court cannot ordinarily reconsider or overrule the decision of a prior panel. United States v. Gay, 967 F.2d 322, 327 (9th Cir.) (Gay), cert. denied, 506 U.S. 929, 113 S.Ct. 359, 121 L.Ed.2d 272 (1992). This principle, that three-judge panels must respect binding circuit precedent, applies even if we believe that precedent to be erroneous. The Sheriffs various arguments that Pettaway misinterpreted Ashe v. Swenson, 397 U.S. 436, 90 S.Ct. 1189, 25 L.Ed.2d 469 (1970), can be entertained only by this court sitting en banc.
B.
The Sheriffs second ground for questioning Pettaway is more compelling, because no panel of this court can have ultimate authority over a question of California law. Our colleagues on the California Supreme Court recently informed us that Pettaway “misunderstood the relevant state law,” and urged us to reconsider that decision at the earliest opportunity. Santamaria, 8 Cal.4th at 923-26, 35 Cal.Rptr.2d 624, 884 P.2d 81.
We held in Pettaway that a jury finding of “not true” on a California sentence-enhancement charge implicates the collateral estop-pel component of the Double Jeopardy Clause, which the Supreme Court recognized in Ashe. Pettaway, 943 F.2d at 1047-48. If the defendant’s conviction is subsequently reversed on appeal, that “not true” finding therefore bars the prosecution from relying at retrial on any theory of the offense factually inconsistent with it. In Pettaway, the jury found the defendant guilty of murder, but found “not true” two sentence enhancement charges that he had personally used a firearm and personally inflicted great bodily injury. The murder conviction was reversed on appeal, and at the retrial the prosecution proposed to introduce evidence tending to show that Pettaway personally shot the victim. We held that a retrial on that theory would be inconsistent with the first jury’s “not true” findings, and would therefore violate the Double Jeopardy Clause. Id. at 1048.
The Sheriff and the California Supreme Court contend that Pettaway rested on the erroneous state-law assumption that the defendant could be convicted of murder only either (1) as a direct perpetrator, or (2) as an aider and abettor. California law apparently permits a third alternative.
It is settled that as long as each juror is convinced beyond a reasonable doubt that defendant is guilty of murder as that offense is defined by statute, it need not decide unanimously by which theory he is guilty. More specifically, the jury need not decide unanimously whether defendant was guilty as the aider and abettor or as the direct perpetrator.
Santamaria, 8 Cal.4th at 918, 35 Cal.Rptr.2d 624, 884 P.2d 81 (citations omitted). Petta-way’s first jury might, therefore, have concluded beyond a reasonable doubt that he was either an aider and abettor or the direct perpetrator, without definitely endorsing either theory. Its “not true” finding on the weapon enhancement charge might then simply reflect a reasonable doubt on the “direct perpetrator” theory.
Under this analysis, there would have been nothing inconsistent about retrying Pettaway under the “either/or” theory. “The first jury convicted the defendant of murder, finding that he was either the direct perpetrator or the aider and abettor. If the second jury does the same, the verdicts would be consistent, not inconsistent.” Id. at 924, 35 Cal. Rptr.2d 624, 884 P.2d 81. Evidence tending to show that Pettaway personally used a gun would also have been admissible at retrial to prove that he was “either a direct and active perpetrator or the aider and abettor,” although it would not have been admissible to prove solely that he was the direct perpetrator. See id. at 932-33, 35 Cal.Rptr.2d 624, 884 P.2d 81 (Mosk, J., concurring and dissenting).
This case presents the same issue. Santamaria’s first jury may have found beyond a reasonable doubt that he was either a direct perpetrator or an aider and abettor, but harbored a reasonable doubt that he was *1356a direct perpetrator. Collateral estoppel obviously prevents the State from seeking the “deadly weapon” sentence enhancement again at retrial. But, the Sheriff argues, a conviction at retrial under the “either/or” theory would not be logically inconsistent with the first jury’s “not true” enhancement finding, even if evidence is presented which tends to suggest that Santamaría personally used a knife.
We understand the Sheriffs argument, but fidelity to our precedent requires us to reject it. The Sheriffs contention that Pettaway “overlooked” the “either/or” theory of murder under state law is inaccurate. The view now urged by the Sheriff was not “overlooked”; the district court in Pettaway relied upon it to deny the writ, and we discussed it in our opinion. Pettaway, 943 F.2d at 1044. We held in Pettaway that this rationale “assumes that collateral estoppel does not apply unless the issue previously determined was necessary to the question of guilt or innocence.” Id. We then explained at length why the jury’s factual finding on the weapon enhancement charge was entitled to preclu-sive effect even though it “was not formally necessary for a finding of guilt on the murder charge.” Id.
The jury was instructed that it had the duty to determine whether the state had proven beyond a reasonable doubt that Pettaway fired the handgun. Thus, the issue of use was tried to the jury in a proceeding with all the “hallmarks of a trial on guilt or innocence,” and was “necessarily determined” for the purposes of collateral estoppel.
Id. at 1045 (footnote omitted).
That may be a less than satisfactory response, because the Sheriff had also argued that, even if the factual finding is preclusive, a subsequent conviction under the “either/or” theory could be consistent with it. Our opinion in Pettaway does not contain a fully persuasive response to that point. The opinion does make it clear, however, that we were aware of the complex state law problem which the Sheriff now urges us to consider. See id. at 1044 (quoting the district court’s description of the “either/or” theory).
Pettaway may have given insufficient attention to this complex problem. Or, it may have rejected the technical, legalistic conception of “inconsistency” now urged by the Sheriff. Regardless, any error in Petta-way ’s final holding was an error of federal law. We do not agree that state law is “the proper source for determining the meaning of the jury’s verdicts and whether the issues are identical.” Santamaria, 8 Cal.4th at 917, 35 Cal.Rptr.2d 624, 884 P.2d 81. The Supreme Court reaffirmed recently that “[t]he preclusive effect of the jury’s verdict ... is a question of federal law which we must review de novo.” Schiro v. Farley, 510 U.S. 222, 232, 114 S.Ct. 783, 790-91, 127 L.Ed.2d 47 (1994). Pettaway considered these arguments, and concluded as a matter of federal law that the use at retrial of evidence tending to show that Pettaway used a gun would “violate double jeopardy principles.” Petta-way, 943 F.2d at 1048. Right or wrong, we are bound by that conclusion. The arguments of the Sheriff, and our concurring colleague, must be addressed to this court sitting en bane.
C.
A three-judge panel can revisit prior Ninth Circuit precedent on a federal issue when “an intervening Supreme Court decision undermines an existing precedent of the Ninth Circuit, and both eases are closely on point.” Gay, 967 F.2d at 327, quoting United States v. Lancellotti, 761 F.2d 1363, 1366 (9th Cir.1985). The Sheriff argues that Pett-away has been substantially undermined by the Supreme Court’s intervening decisions in Caspari and Dixon.
Dixon dealt with when a successive prosecution is for the “same offense” as an earlier prosecution, and thus barred by the claim-preclusion aspect of the Double Jeopardy Clause. Under Blockburger v. United States, 284 U.S. 299, 52 S.Ct. 180, 76 L.Ed. 306 (1932), offenses were considered different for Double Jeopardy purposes as long as each “require[d] proof of an additional fact which the other d[id] not.” Id. at 304, 52 S.Ct. at 182. In Grady v. Corbin, 495 U.S. 508, 110 S.Ct. 2084, 109 L.Ed.2d 548 (1990), the Supreme Court departed from Blockbur-*1357ger and held that offenses would also be considered the same “if, to establish an essential element of [the new offense], the government will prove conduct that constitutes an offense for which the defendant has already been prosecuted.” Id. at 510, 110 S.Ct. at 2087.
Pettaway recognized that “[t]he present case presents essentially the same situation” as Grady, and quoted extensively from that opinion. Pettaway, 943 F.2d at 1046-47. That is hardly surprising; by adopting a more fact-driven approach to the meaning of “same offense,” Grady blurred the line between the former claim preclusion (Blockbur-ger) and issue preclusion (Ashe) aspects of the Court’s Double Jeopardy jurisprudence.
In Dixon, the Supreme Court overruled Ch'ady and returned to the Blockburger test for claim preclusion. Nonetheless, the demise of Grady in the “same offense” context does not undermine Pettaway’s conclusions in the very different context of issue preclusion. Dixon recognized that Ashe may sometimes bar prosecutions when Blockbur-ger would not. “The collateral-estoppel effect attributed to the Double Jeopardy Clause may bar a later prosecution for a separate offense where the Government has lost an earlier prosecution involving the same facts.” Dixon, 509 U.S. at 705, 113 S.Ct. at 2860 (citation omitted). The Court also pointed out that “[o]f course the collateral-estoppel issue is not raised in this case.” Id. Dixon is not closely on point with Pettaway.
Caspari held only that an extension of Bullington v. Missouri, 451 U.S. 430, 101 S.Ct. 1852, 68 L.Ed.2d 270 (1981) (Bulling-ton), beyond the context of capital sentencing would be a “new rule” for purposes of Teague v. Lane, 489 U.S. 288, 109 S.Ct. 1060, 103 L.Ed.2d 334 (1989). Caspari, 510 U.S. at 396-97, 114 S.Ct. at 956-57. Bullington’s core holding was that when the death penalty phase of a capital trial bears “the hallmarks of the trial on guilt or innocence,” the Double Jeopardy Clause bars retrial of that proceeding if the state fails to obtain a death sentence. Bullington, 451 U.S. at 439, 101 S.Ct. at 1858. Pettaway cited the “hallmarks” language above, as well as numerous other sources, in its discussion of whether the critical issue was “necessarily decided” in Pettaway’s first trial. Pettaway, 943 F.2d at 1044. Bullington’s, vitality in non-capital cases is not critical to Pettaway; in any event, Cas-pari did not decide that issue on the merits.
The Supreme Court carefully limited the holdings of both Dixon and Caspari. Dixon did not decide any collateral estoppel issues, and Caspari held only that Bullington cannot be extended on collateral review because of the non-retroactivity principle of Teague. Neither of these cases are closely on point with Pettaway, and neither “undermine” that decision enough for this panel to overrule it. Our reliance on Pettaway in several recent decisions, without indicating any doubt as to its continuing vitality, strengthens this conclusion. See United States v. McLaurin, 57 F.3d 823, 826-27 (9th Cir.1995); United States v. Weems, 49 F.3d 528, 531-32 (9th Cir.1995).
We conclude that we are bound by the collateral estoppel analysis of Pettaway. It was therefore not error for the district court to issue the writ of habeas corpus.
AFFIRMED.