The Insanity Defense Reform Act (IDRA), passed by Congress in 1984, imposed a uniform standard for legal insanity that applies in all federal trials in which [Page 373]the defense is raised; it also established the burden of proof in such cases.

Although criminal law is primarily the province of the individual states, the federal government has independent jurisdiction to prosecute criminal activity that concerns the federal government. In 1984, all the states and the federal criminal law had some version of the insanity defense, but the federal criminal code did not contain an insanity defense. Instead, each of the courts of appeal in the 11 federal judicial circuits had judicially adopted an insanity defense that applied in that circuit.

Ten of the 11 circuit courts of appeal ...