State v. Grell: Placing the Burden on Defendants to Prove Mental Retardation in Capital Cases

In State v. Grell, the Arizona Supreme Court addressed the question of whether placing such a burden on a defendant is unconstitutional in light of the U.S. Supreme Court’s decision in Atkins v. Virginia, which held that the execution of a mentally retarded criminal defendant constitutes cruel and unusual punishment, in violation of the Eighth Amendment of the U.S. Constitution. Emphasizing that Atkins allows states to develop appropriate ways to enforce this constitutional restriction, the court held in a 4 to 1 decision that Arizona may place the burden on the defendant to prove mental retardation, and that the clear and convincing standard withstands constitutional scrutiny. The court further held that a jury determination of mental retardation is not required.