–Michael Louis Corrado
The decision in the recent case of Kahler v. Kansas before the SCOTUS involves important issues in criminal jurisprudence. In this paper, an attempt has been made to trace the nuances of the different forms of defence the insanity plea can take and the practical implications of the same against the background of the Kahler case. The issue before the SCOTUS in this case was whether the elimination of any affirmative defence of insanity, and mere provision of a mens rea defence, would amount to denial of due process. In this paper, it is contended that a historical understanding of mens rea shows that the concept, as it is understood today, differs from what it meant in the 19th century legal landscape. Thus, a mens rea approach to insanity then amounted to what is now known as an affirmative defence in several cases. However, a mens rea approach today would exclude evidence of mental illness which only affects the appreciation of the nature of the offence, without affecting the formulation of the intention to commit the specific offence. It is further contended that the State’s arguments before the SCOTUS in Kahler reveal the inconsistency between the mens rea approach and American legal history and tradition, and that the State, thus, does not sufficiently discharge its burden of showing that an affirmative defence is not required.