Diminished capacity as an alternative to McNaghten in California law.

Dr. Diamond's courageous defense of the diminished capacity plea in People v. Gorshen (1959) emphasized mental disturbances negating malice aforethought. Diminished capacity as a defense in California remained effective from 1978 to 1982 until overturned by a modified American Law Institute rule. Diamond's advocacy of psychologic elements, including motivation, did much to enliven forensic thinking re: the death sentence and the fated diminished capacity defense.