After finding petitioner Stringer guilty of capital murder, a Mississippi jury, in the sentencing phase of the case, found that there were three statutory aggravating factors. These included the factor the murder was "especially heinous, atrocious or cruel," which had not been otherwise defined in the trial courts instructions. Stringer was sentenced to death, the sentence was affirmed by the State Supreme Court on direct review, and postconviction relief was denied in the state courts. The Federal District Court then denied him habeas corpus relief, rejecting his contention that the "heinous, atrocious or cruel" aggravating factor was so vague as to render the sentence arbitrary, in violation of the Eighth Amendments proscription of cruel and unusual punishment. The Court of Appeals ultimately affirmed, holding that Stringer was not entitled to rely on Clemons v. Mississippi, 494 U.S. 738, or Maynard v. Cartwright, 486 U.S. 356, in his habeas corpus proceedings because those decisions, which were issued after his sentence became final, announced a "new rule" as defined in Teague v. Lane, 489 U.S. 288.

Held:

In a federal habeas corpus proceeding, a petitioner whose death sentence became final before Maynard and Clemons were decided is not foreclosed by Teague from relying on those cases. Pp. 227-237.

(a) When a petitioner seeks federal habeas relief based on a principle announced after a final judgment, Teague requires a federal court to determine, first, whether the decision in question announced a new rule, i.e., was not dictated by precedent existing when the judgment became final. If the answer is yes and neither of two exceptions apply, the decision is not available to the petitioner. Second, if the decision did not announce a new rule, it is necessary to inquire whether granting the relief sought would create a new rule because the prior decision is applied in a novel setting, thereby extending the precedent. See Butler v. McKellar, 494 U.S. 407, 414-415. P. 227-228.

(b) For purposes of Teague, Maynard did not announce a new rule. Its invalidation of Oklahomas "especially heinous, atrocious, or cruel" aggravating circumstance was controlled by Godfrey v. Georgia, 446 U.S. 420, in which the Court held that Georgias aggravating circumstance that the killing was "outrageously or wantonly vile, horrible and [503 U.S. 222, 223] inhuman" was vague and imprecise, inviting arbitrary and capricious application of the death penalty in violation of the Eighth Amendment. Pp. 228-229.

(c) This Court rejects the States contention that, at the time Stringers conviction became final and before Clemons, it would have been a new rule to apply the Godfrey and Maynard holdings to the Mississippi sentencing system because of differences between the use of aggravating factors in that system and their use in the Georgia system in Godfrey. The principal - and critical - difference between the two schemes is that Mississippi, unlike Georgia, is a "weighing" State, in which a jury that has found a defendant guilty of capital murder and found at least one statutory aggravating factor must weigh such factors against the mitigating evidence. Zant v. Stephens, 462 U.S. 862, 890, expressly left open the possibility that, in a weighing State, infection of the process with an invalid aggravating factor might require invalidation of the death sentence. Although Clemons later held that the appellate court in such a case could reweigh the aggravating and mitigating circumstances or undertake harmless error analysis, this Court has not suggested that the Eighth Amendment permits a weighing state appellate court to affirm a death sentence without a thorough analysis of the role an invalid aggravating factor played in the sentencing process, but has required such courts to implement the well-established requirement of individuali