Clark v. Arizona

Clark (defendant), who suffered from paranoid schizophrenia, was charged with first-degree murder for intentionally killing a police officer. At his bench trial, he pleaded not guilty by reason of insanity and tried to introduce expert testimony about his schizophrenia both to support the insanity defense and to negate mens rea — the intent required for the crime. Under Arizona's rule from State v. Mott, the judge allowed the mental-illness evidence on insanity but barred it on mens rea. The judge rejected the insanity defense and convicted Clark. The Arizona courts affirmed, and the U.S. Supreme Court granted certiorari to decide whether the Mott restriction violates Due Process.