Insanity defense
The question of who bears the burden of proof is an issue in the United States. Before the John Hinckley, Jr. trial the burden of proof rested with the government in most states. Afterwards many of these states required the defense to prove the defendant was legally insane. Where the state still bears the burden of proof, the standard for the prosecution is beyond a reasonable doubt. Where the defense bears the burden, the standard is preponderance of the evidence (a lower standard).