In this habeas appeal, the petitioner was convicted of two murders in 1992 in Arizona state court. At that time, no requirement existed that the jury determine facts supporting an aggravating factor. At least one aggravating factor must be found to support a sentence of death under the Court’s precedents. In the petitioner’s case, the trial court found factors in aggravation for both murders and imposed death. In federal habeas proceedings 20 years later, the Ninth Circuit found that the trial court improperly ignored mitigation evidence in violation of Eddings v. Oklahoma, 455 U.S. 104 (1982) (reversible error for trial court to ignore relevant mitigation evidence at capital sentencing). The case returned to the Arizona Supreme Court, where the petitioner argued for a new sentencing hearing before a jury. The Arizona Supreme Court rejected this argument, pointing to Clemons v. Mississippi, 494 U.S. 738 (1990). Clemons allows a state appellate court to reweigh aggravating and mitigating factors in a death case following reversal for use of an improper aggravating factor (instead of a jury weighing those factors). The Arizona Supreme Court reweighed the sentencing factors in the case and again imposed death. The petitioner appealed to the U.S. Supreme Court, arguing that a jury should have made that determination. A majority of the court disagreed and affirmed the death sentence.

The court first rejected the argument that Clemons did not apply because that case involved an improper aggravating factor, whereas the petitioner’s case involved a failure to consider a mitigation factor.

. . . [T]he Court’s decision in Clemons ruled that appellate tribunals may perform a ‘reweighing of the aggravating and mitigating evidence.’ In short, a Clemons reweighing is a permissible remedy for an Eddings error. 

The court also rejected the argument that Clemons was overruled by Ring v. Arizona, 536 U. S. 584 (2002), and Hurst v. Florida, 136 S. Ct. 616 (2016), which require a jury to determine facts supporting an aggravating factor. The petitioner argued that an appellate court could no longer reweigh aggravating factors under those cases and that a jury determination was required. This too was rejected. A jury need only find the facts in support of the aggravated factor; states are free to allow the trial court to make the ultimate decision on whether to impose a death sentence, so long as any facts necessary to support the aggravating factor were found by a jury. The court noted:

. . .[I]n a capital proceeding just as in an ordinary sentencing proceeding, a jury (as opposed to a judge) is not constitutionally required to weigh the aggravating and mitigating circumstances or to make the ultimate sentencing decision within the relevant sentencing range. . . In short, Ring and Hurst did not require jury weighing of aggravating and mitigating circumstances, and Ring and Hurst did not overrule Clemons so as to prohibit appellate reweighing of aggravating and mitigating circumstances.

The petitioner also pointed to the fact that no jury determined the facts of the factors in aggravation supporting his death sentence as Ring and Hurst require. This claim was foreclosed by the fact that Ring and Hurst were decided after the petitioner’s direct appeal became final. Those cases therefore do not apply retroactively to cases (like the petitioner’s) on collateral review under Schriro v. Summerlin, 542 U.S. 348. The court rejected the argument that the Arizona Supreme Court’s reweighing of aggravating and mitigating factors re-opened direct review. The Arizona Supreme Court categorized its decision as collateral review, and the U.S. Supreme Court declined to disturb that interpretation of state law. “As a matter of state law, the reweighing proceeding in McKinney’s case occurred on collateral review.” Id. at 8 (emphasis in original). The Arizona Supreme Court’s judgment was consequently affirmed by a 5-4 majority. Chief Justice Roberts, and Justices Alito, Gorsuch, and Thomas joined the majority opinion.

Justice Ginsberg dissented, joined by Justices Breyer, Sotomayor, and Kagan. The dissenting justices disagreed with the majority that the Arizona Supreme Court’s action in reweighing sentencing factors was a collateral proceeding. In their view, that proceeding was a re-opening of direct appeal proceedings, and Ring applied. The dissenting justices would have found the death sentence unconstitutional and reversed the judgment of the Arizona Supreme Court.