State v. Herrera

In 1983, Utah replaced its traditional insanity defense with a statute limiting the defense to whether mental illness caused the defendant to lack the mental state required for the crime charged, eliminating the older "didn't know it was wrong" formulation. Herrera and Sweezy (defendants) pleaded not guilty by reason of insanity and moved to have the amended statute declared unconstitutional, arguing it violated federal due process by allowing conviction even without proof they knew their conduct was wrong, violated state due process, and improperly shifted the burden of proving an element of the crime onto them.