[1] In 1994, Lorena Bobbitt was found not guilty when her defense argued that an irresistible impulse led her to cut off her husband's penis.
The Penal Code of the U.S. state of California states (2002), "The defense of diminished capacity is hereby abolished ... there shall be no defense of ... diminished responsibility or irresistible impulse..."[2][3] The "policeman at the elbow" test is a test used by some courts to determine whether the defendant was insane when they committed a crime.
It is a variant of the M'Naghten Rules that addresses the situation in which the defendant knew that what they were going to do was wrong, but had no ability to restrain themself from doing it.
broadened the definition of "abnormality of mind" to include those lacking "the ability to exercise will-power to control acts in accordance with [their] rational judgment".
Thus it operates only as a partial defence to murder, reducing the charge to manslaughter, and giving the judge discretion as to length of sentence and whether committal would be more appropriate than incarceration.