ALI rule

{{Short description|Guideline governing legal pleas of insanity}}

{{One source|date=May 2024}}

The ALI rule, or American Law Institute Model Penal Code rule, is a recommended rule for instructing juries how to find a defendant in a criminal trial is not guilty by reason of insanity.Criminal Law - Cases and Materials, 7th ed. 2012, Wolters Kluwer Law & Business; John Kaplan, Robert Weisberg, Guyora Binder, {{ISBN|978-1-4548-0698-1}}, [https://law.stanford.edu/publications/criminal-law-cases-and-materials-7th-edition/]{{rp|614–5}} It broadened the M'Naghten rule of whether a defendant was so mentally ill that he is unable to "know" the nature and quality of his criminal act, or know its wrongfulness, to a question of whether he had "substantial capacity to appreciate the criminality of [his] conduct".{{rp|614–5}} It also added a volitional component as to whether defendant was lacking in "substantial capacity to conform his conduct to the law".{{rp|614–5}}

It arose from the case of United States v. Brawner.{{rp|634}}, in which the court first adopted the American Law Institute's Model Penal Code rule, thereby moving away from the Durham rule.

The ALI rule is:

::"(1) A person is not responsible for criminal conduct if at the time of such conduct as a result of mental disease or defect he lacks substantial capacity either to appreciate the criminality of his conduct or to conform his conduct to the requirements of the law.

::"(2) As used in this Article, the terms "mental disease or defect" do not include an abnormality manifested only by repeated criminal or otherwise antisocial conduct [Section 4.01]."