MPC substantial-capacity test

The insanity-defence standard from the Model Penal Code (ALI, 1962) § 4.01: not responsible if, as a result of mental disease or defect, the person lacks substantial capacity to appreciate the criminality of the conduct or to conform conduct to legal requirements. Contains both cognitive (appreciate) and volitional (conform) limbs. Adopted by most US jurisdictions; volitional limb abandoned federally after Hinckley.