In 1982, an Arizona jury convicted respondent Robert Douglas Smith of first-degree murder, kidnaping, and sexual assault. He was sentenced to death. The convictions and sentence were affirmed on direct appeal, and Smith’s state petitions for posteonviction relief proved unsuccessful. Smith then filed a petition for a writ of habeas corpus in the United States District Court for the District of Arizona. In none of these proceedings did Smith argue that he was mentally retarded or that his mental retardation made him ineligible for the death penalty. Smith had, however, presented *7 evidence in mitigation during the sentencing phase of his trial showing that he had low intelligence.
The District Court denied Smith’s petition for habeas corpus in 1996. Following several rounds of appeals, remands, and petitions for certiorari to this Court (including one successful petition by the State, see
Stewart
v.
Smith,
The State’s petition for certiorari is granted,
*
the judgment of the Court of Appeals is vacated, and the case is remanded. The Ninth Circuit erred in commanding the Arizona courts to conduct a jury trial to resolve Smith’s mental retardation claim.
Atkins
stated in clear terms that “ ‘we leave to the State[s] the task of developing appropriate ways to enforce the constitutional restriction upon [their] execution of sentences.’ ”
Because the Court of Appeals exceeded its limited authority on habeas review, the judgment below is vacated, and the case is remanded for further proceedings consistent with this opinion.
It is so ordered.
Notes
Srmth’s motion to proceed informa pauperis is also granted.
