Clark killed a policeman. He
was arrested and charged with first-degree murder.
First-degree murder requires that the defendant intentionally or knowingly killed the victim.
At Trial Clark argued that he
was insane as was under the delusion that aliens were impersonating
Clark argued that his
inability to understand the nature of his acts at the time they were
committed should be a sufficient basis for an insanity defense.
Basically, Clark was saying
that he should be allowed to claim that his insanity prohibited him from
forming intent (aka mens
rea), and so he could not be found
guilty of a crime that requires intent.
The Trial Court found Clark
guilty of first-degree murder. He
The Trial Court found that,
although Clark was crazy, his schizophrenia did not prevent him from
knowing right from wrong, therefore he could not claim insanity as a defense.
Basically, even though
Clark thought the policeman was an alien, he was still competent enough
to know that shooting him would result in death, and that killing
someone was a crime.
Arizona only allows an
insanity defense if a defendant is unable to tell right from wrong.
The Appellate Court upheld the
conviction. Clark appealed.
The Arizona Supreme Court
The US Supreme Court upheld
The US Supreme Court found
that it is not a violation of due process to have an insanity test stated solely in terms of the capacity
to tell whether an act charged as a crime was right or wrong.
Arizona could also
constitutionally limit a defendant's evidence of mental defect to only
what is relevant to that insanity test, even when mens rea is an element of the charged crime.
Most States do not impose a
restriction on the use of mental health evidence to rebut a requirement of
mens rea, but several (including
Arizona) do. This decision said that restriction is not a violation of due
Some States (like
California), have a partial restriction, where the evidence can be used
to rebut intent only in crimes
that involve a specific intent,
not those that require only a general intent.