The Ford v. Wainwright case in 1985 was a significant ruling by the U.S Supreme Court that addressed the issue of executing mentally ill prisoners. Alvin Bernard Ford, who had been sentenced to death for murder, developed severe mental illness while on death row and his lawyers argued that he was too insane to be executed. The court ruled in favor of Ford with a 5-4 majority decision stating it is unconstitutional under the Eighth Amendment's ban on cruel and unusual punishment to execute an individual who is insane at the time of execution. However, they did not provide specific guidelines for determining insanity leading states to establish their own standards which varied widely across jurisdictions.

In the dissenting opinion for Ford v. Wainwright, Justice Powell argued that while it is unconstitutional to execute a prisoner who has become insane after sentencing, there should be no constitutional bar against executing a prisoner whose sanity is in question at the time of execution. He believed that if a competent court determines after full and fair hearing that such person understands the nature of the punishment and why he or she is receiving it, then they can be executed constitutionally. Furthermore, he disagreed with majority's decision to allow federal courts to review state-court determinations on this issue de novo (from scratch). Instead, he suggested these decisions should only be overturned if found unreasonable by federal standards.