It was John Hinckley, Jr.'s assassination attempt on President Reagan outside the Washington Hilton in 1981 that ignited a change in the U.S.'s way of thinking about how a person's insanity is evaluated and determined in the eyes of the law. Hinckley was tried and found not guilty by reason of insanity in 1982 and confined to a psychiatric hospital. The verdict stunned the country -- a poll at the time found 76 percent of Americans felt Hinckley should have been convicted and incarcerated -- and more than 40 bills went before Congress in an effort to put an end to the insanity defense [source: Lilienfeld].
The insanity defense was not abolished, though, and the Comprehensive Crime Control Act (CCCA) was passed in 1984. Under the mental health provisions in the CCCA, a defendant must prove that because of mental illness or mental defect he did not have the cognitive or moral ability to comprehend his criminal acts at the time of the crime. The competency of the defendant must be determined (including competency to stand trial, to plead guilty or no contest, and to waive counsel, as well as competency at sentencing and during appeal), and sentencing is to be determined under the included Insanity Defense Reform Act, which sets sentencing guidelines intended to protect mentally ill criminals.