State v. Mustafa

Amicus brief arguing that a categorical rule requiring a defendant to present expert testimony in order to raise a diminished capacity defense is unconstitutional.

This case raises an issue closely related to the one presented in State v. Arrington: the constitutionality of a categorical rule that lay testimony is inadequate to support a diminished capacity defense. Our brief argues the text of the diminished capacity statute exposes an imperfect fit between the questions bearing on criminal responsibility and the information a medical expert may supply. In requiring expert testimony, the Appellate Division distorted the historic diminished capacity standard. Moreover, the Appellate Division effectively rejected the sufficiency of all future lay testimony on diminished capacity. Prospective categorical exclusions of this kind are incompatible with due process.