Clark v. Arizona

Summary

The Supreme Court held that Arizona’s abbreviated insanity test and its rule excluding mental illness evidence from mens rea deliberations do not violate due process. The Court reasoned that states have flexibility in defining legal insanity and that limiting capacity evidence to the insanity defense serves to avoid confusion about expert opinions on mental state. Justice Breyer concurred in part and dissented in part, concerned about the application of the distinction among evidence types and the need for remand.