NOTE: Where it is feasible, a syllabus (headnote) will be released, as is being done in connection with this case, at the time the opinion is issued. The syllabus constitutes no part of the opinion of the Court but has been prepared by the Reporter of Decisions for the convenience of the reader. See United States v. Detroit Lumber Co., 200 U. S. 321, 337.

SUPREME COURT OF THE UNITED STATES

Syllabus

O'NEAL v. McANINCH, WARDEN

certiorari to the united states court of appeals for the sixth circuit

No. 93–7407. Argued October 31, 1994—Decided February 21, 1995

In proceedings on Robert O'Neal's federal habeas corpus petition challenging his state-court convictions for murder and other crimes, the Sixth Circuit assumed that O'Neal had established constitutional ``trial'' error with regard to one of the jury instructions, but disregarded that error on the ground that it was ``harmless.'' After setting forth the harmlessness standard normally used by federal habeas courts—whether the error had a ``substantial and injurious effect or influence in determining the jury's verdict,'' see, e.g., Brecht v. Abrahamson, 507 U. S. ___, ___—the Sixth Circuit stated that the habeas petitioner must bear the ``burden of establishing'' whether the error was prejudicial under that standard. As a practical matter, the court's burden-of-proof statement apparently means that the petitioner must lose if a reviewing judge is in grave doubt about the effect on the jury of this kind of error, i.e., if, in the judge's mind, the matter is so evenly balanced that he or she feels in virtual equipoise as to the error's harmlessness.

Held: When a federal habeas court finds a constitutional trial error and is in grave doubt about whether the error had a ``substantial and injurious effect or influence in determining the jury's verdict,'' the error is not harmless, and the petitioner must win. Pp. 3–12.

(a) The foregoing legal conclusion rests upon three considerations. First, it is supported by precedent. See, e.g., Kotteakos v. United States, 328 U. S. 750, 764–765; Chapman v. California, 386 U. S. 18, 24. Brecht, supra, at ___, and Palmer v. Hoffman, 318 U. S. 109, 116, distinguished. The State's view that appellants' ``burden'' of showing ``prejudice'' in civil cases applies to habeas proceedings fails to take into account the stakes involved in a habeas proceeding. Unlike the civil cases cited by the State, the errors being considered by a habeas court occurred in a criminal proceeding, and therefore, although habeas is a civil proceeding, someone's custody, rather than mere civil liability, is at stake. Moreover, precedent suggests that civil and criminal harmless-error standards do not differ in their treatment of grave doubt as to the harmlessness of errors affecting substantial rights. Compare, e.g., Fed. Rule Crim. Proc. 52(a) with Fed. Rule Civ. Proc. 61. Second, the Court's conclusion is consistent with the basic purposes underlying the writ of habeas corpus. A legal rule requiring issuance of the writ will, at least often, avoid the grievous wrong of holding a person in custody in violation of the Constitution and will thereby both protect individuals from unconstitutional convictions and help to guarantee the integrity of the criminal process by assuring that trials are fundamentally fair. In contrast, although denying the writ in cases of grave uncertainty would help protect the State's interest in the finality of its judgments and would promote federal-state comity, such a rule would also virtually guarantee that many, in fact, would be wrongly imprisoned or executed, and would tell judges who believe individuals are quite possibly being held in unlawful custody that they cannot grant relief. Third, the rule adopted herein has certain administrative virtues: It is consistent with the way that courts have long-treated important trial errors and avoids the need for judges to read lengthy records to determine prejudice in every habeas case. These factors are not determinative, but offer a practical caution against a rule that, in respect to precedent and purpose, would run against the judicial grain. Pp. 4–10.

(b) Contrary to the State's argument, there is nothing in the language of the habeas corpus statute, 28 U. S. C. §2254(a), that tells a court to treat a violation as harmless when it is in grave doubt about harmlessness. Indeed, there is no significant support for either side in any of the language of the relevant statutes or Rules. In these circumstances, the Court properly undertakes the foregoing examination, looking first to the considerations underlying its habeas jurisprudence, and then determining whether the proposed rule will advance or inhibit these considerations by weighing the marginal costs and benefits of its application on collateral review. See Brecht, supra, at ___. Pp. 10–12.

3 F. 3d 143, vacated and remanded.

Breyer, J., delivered the opinion of the Court, in which Stevens, O'Connor, Kennedy, Souter, and Ginsburg, JJ., joined. Thomas, J., filed a dissenting opinion, in which Rehnquist, C. J., and Scalia, J., joined.