Penry v. Lynaugh/Concurrence Stevens
Justice STEVENS, with whom Justice BLACKMUN joins, concurring in part and dissenting in part.
As I stated in my separate opinion in Teague v. Lane, 489 U.S. 288, 318-319, and n. 2, 109 S.Ct. 1060, 1080, n. 2, 103 L.Ed.2d 334 (1989), it is neither logical nor prudent to consider a rule's retroactive application before the rule itself is articulated. Nor am I at all sure that courts should decide the retroactivity issue if it was not raised below. Cf. Zant v. Moore, 489 U.S. 836, 837, 109 S.Ct. 1518, 1519, 103 L.Ed.2d 922 (1989) (BLACKMUN, J., dissenting). Finally, I do not support the Court's assertion, without benefit of argument or briefing on the issue, that Teague § retroactivity principles pertain to capital cases. Cf. Teague, 489 U.S., at 321, and n. 3, 109 S.Ct., at 1081, and n. 3 (STEVENS, J., concurring in part and concurring in judgment). But assuming, arguendo, that those principles do apply, it is clear that the Court's discussion of the mitigating evidence question, with which I agree, does not establish a "new rule" as that term is used for retroactivity purposes. I thus join Parts I, II-B, and III.
In Part IV-A the Court decides that a rule that the Eighth Amendment prohibits the execution of a mentally retarded person ought to apply retroactively. Assuming retroactivity is pertinent, I agree that the first exception to Justice Harlan's nonretroactivity doctrine "should be understood to cover not only rules forbidding criminal punishment of certain primary conduct but also rules prohibiting a certain category of punishment for a class of defendants because of their status or offense," ante, at 330, and that this claim lies within that exception. #fn-s-1 
The remaining sections of Part IV adequately and fairly state the competing arguments respecting capital punishment of mentally retarded persons. In my judgment, however, that explication particularly the summary of the arguments advanced in the Brief for American Association on Mental Retardation et al. as Amici Curiae, ante, at 336-337-compels the conclusion that such executions are unconstitutional. I would therefore reverse the judgme t of the Court of Appeals in its entirety.