In 1989, the U.N. Economic and Social Council adopted a resolution which recommended the same. Mental retardation is a mental disability distinct from mental illness. The United States Supreme Court ruled in 1986 that the Eighth Amendment prohibits the execution of insane prisoners. Most U.S. jurisdictions have provisions which prohibit the execution of prisoners judged to be insane, but their diagnostic procedures vary widely. In many states the decision to refer a prisoner for psychiatric assessment rests with prison administrators.
Some states have provisions requiring treatment of condemned prisoners who become mentally ill.
In clear violation of international standards, mentally impaired people have been executed in the United States. The prohibition against executing insane prisoners recognizes that killing people who cannot comprehend the nature or purpose of their punishment serves no deterrent or retributive function. In addition, common law traditionally maintains that mentally-ill people may not be capable of pursuing available appeals or preparing themselves, in keeping with religious or humanitarian principles, for death. The 1993 execution of Christopher Burger indicates the questionable standards applied in some United States capital cases. Christopher Burger and an accomplice were convicted of murdering a man in 1977, when Burger was 17 years old.