52 NY 467 (1873)
The insanity defense was a feature of many high-profile murder cases during the Gilded Age. The most famous example was that of the disgruntled officer seeker who claimed that God had commanded him to assassinate President James Garfield (United States v. Guiteau,10 F. 161 [1882]).
The criminal defense of insanity, considered an excuse rather than a justification for criminal behavior, has been recognized for thousands of years. Its modern form took shape following Daniel M’Naghten’s attempted assassination of British Prime Minister Robert Peel in 1843. Believing that Peel was conspiring against him, M’Naghten ended up killing Peel’s secretary, whom he mistook for Peel. A jury found him not guilty by reason of insanity, causing a public uproar that led Queen Victoria to demand that the House of Lords establish a legal standard for the insanity defense. A panel of English judges helped develop the “M’Naghten Rule:”
[T]o establish a defense on the ground of insanity, it must be proved that, at the time of the committing of the act, the party accused was laboring under such a defect of reason, from disease of the mind, as not to know the nature and quality of the act he was doing; or if he did know it, that he did not know he was doing what was wrong.
The 1873 case of Flanagan v. People established the M’Naghten Rule as the proper test for the insanity defense in New York. On trial for murdering his wife, Flanagan asserted an alternative to the M’Naghten Rule, namely that he was subject to an “irresistible impulse” that overrode his capacity to choose between right and wrong. The trial judge declined to charge the jury along those lines and adhered to the M’Naghten Rule, which requires the party asserting the defense of insanity to clearly prove that he was “laboring under such a defect of reason from disease of the mind as not to know the nature and quality of the act he was doing; and, if he did know it, that he did not know he was doing wrong.”
Writing for a unanimous court, Judge Andrews rejected Flanagan’s argument that a person is not guilty by reason of insanity where his “faculties are so disordered and deranged that a man, though he perceives the moral quality of his acts, is unable to control them, and is urged by some mysterious pressure to the commission of acts, the consequences of which he anticipates but cannot avoid.” The court reaffirmed that “the test of responsibility for criminal acts, where unsoundness of mind is interposed as a defence, is the capacity of the defendant to distinguish between right and wrong at the time of and with respect to the act which is the subject of the inquiry.” Furthermore, “[t]he doctrine that a criminal act may be excused upon the notion of an irresistible impulse to commit it, where the offender has the ability to discover his legal and moral duty in respect to it, has no place in the law.” As Judge Andrews pointed out, every crime, arguably, was committed under an influence of “evil passions” that “weaken the restraining power of the will and conscience.” The whole point and “object of the law was to compel people to control these influences.”
New York’s definition of insanity, though codified and amended several times in response to evolving state and federal law, has remained essentially true to the M’Naghten Rule. Today, Penal Law § 40.15, entitled “Mental disease or defect,” reads as follows:
In any prosecution for an offense, it is an affirmative defense that when the defendant engaged in the proscribed conduct, he lacked criminal responsibility by reason of mental disease or defect. Such lack of criminal responsibility means that at the time of such conduct, as a result of mental disease or defect, he lacked substantial capacity to know or appreciate either: (1) The nature and consequences of such conduct; or (2) That such conduct was wrong.
Sources
Brian Quinn, “Charles Andrews,” The Judges of the New Court of Appeals, Rosenblatt, ed., Fordham Univ. Press, 2007, at 181.
Richard H. Underwood, Gaslight Lawyers, Shadeland House Modern Press, 2017 at pp. 96-99, 186-187.
Winston Bowman, United States v. Guiteau: Assassination and Insanity in Gilded Age America, Federal Judicial Center 2019.
Eugene M. Fahey, Laura Groschadl and Brianna Weaver, The Angels that Surrounded My Cradle: The History, Evolution and Application of the Insanity Defense, Buffalo Law Review, Vol. 68, No. 3, 2020.