Today, the United States Supreme Court issued it's opinion in McKinner v. Arizona, No. 18-1109 (Feb. 25, 2020). In a 5-to-4 opinion written by Justice Kavanaugh (joined by Roberts, C.J., and Thomas, Alito, and Gorsuch, JJ), the Court held that a reweighing under Clemons v. Mississippi, 494 U.S. 738 (1990) (holding that Constitution does not prevent a state appellate court from upuholding a death sentence that is based in part on an invalid or improperly defined aggravating circumstance eight by reweighing or harmless error), is a permissible remedy for a constitutional error under Eddings v. Oklahoma, 455 U.S. 104 (1982) (holding that a capital sentencer may not refuse as a matter of law to consider relevant mitigating evidence). Further, when an Eddings error is found on collateral review, a state appellate court may conduct a Clemons reweighing on callateral review. Justice Ginsbert filed a dissenting opinion joined by Justices Breyer, Sotomayor and Kagan.
Merits briefing is available on the Supreme Court's website here, and a transcript of the oral argument is available here. The Training Division provides resources and training materials for federal capital habeas counsel through capdefnet.org.