University of Pennsylvania law professor Stephen Morse and Judge Morris Hoffman have posted on SSRN, The Uneasy Entente Between Insanity and Mens Rea: Beyond Clark v. Arizona, commenting on last year's Supreme Court decision in Clark v. Arizona. As discussed here, Clark is a troublesome case and Morse and Hoffman have added their valuable 2 cents to the discussion. Their Article contains too many goodies to expand on here, but here's one good one:

There are no doubt many open conceptual and empirical questions about mental disorders, but the law routinely deals with cases involving people who suffer from them. One way to think of these difficult questions about mental state and blameworthinesses is to analogize them to electricity. Modern physics has exposed the foundations of elemental particles, including the electron, as a kind of mysterious expression of a set of strange and counter-intuitve physical rules; in some ways it seems the more we learn about quantum physics the more our macro-reality seems to be an illusion. Yet those foundational uncertainities hardly disable us from using electricity, or designing circuits.

Morse and Hoffman also do a good job of elucidating the problems with the Court's reasoning between insanity and mens rea. This piece of scholarship is worth reading. See also, Steven K. Erickson, Mind Over Morality, Buffalo Law Review, forthcoming; and Peter Weston, The Supreme Court’s Bout with Insanity: Clark v. Arizona (pdf), 4 Ohio St. J. Crim. L. 143-165 (2006).