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Vol. 107, Issue 4


Insanity Step Zero: A Modern Application of M’Naghten’s Question Four Test

Michael G. Mills, J.D., Cornell Law School, 2021; B.A., Siena College, 2018.

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14 Aug 2022

Defendants suffering from delusion currently are subject to inequitable treatment in our criminal justice system. They can genuinely believe, due to a delusion, that a person right in front of them has a gun and is about to kill them. Acting in what they believe is self-defense, they can draw a gun and kill their would-be assailant. Many in their same situation, facing what they believe to be an imminent threat against their life with no ability to escape, would do the exact same thing. In fact, the law in all fifty states would allow a defendant actually facing such a threat to raise a self-defense claim. However, under many states’ laws, the defendant suffering from delusions still will be found guilty of murder. Mistake of fact doctrines generally require mistakes to be reasonable, so the defendant will not be entitled to a self-defense claim because delusions are inherently unreasonable. Yet only seven states have insanity defenses that explicitly account for delusions. Thus, the jury may still find them guilty under that jurisdiction’s insanity test. This creates a paradox: defendants are too insane to qualify for the mistake of fact doctrine, yet too sane to escape punishment under the insanity defense. This paradox has become increasingly prevalent in recent years, as many jurisdictions seek to abolish or modify their insanity tests—often leaving defendants suffering from delusions behind in the process.

This Note proposes a novel test to fix this paradox: the step zero test. It is built off the fourth answer the Justices gave in the famous M’Naghten Case. While that answer has largely fallen to historical obscurity, my proposed test revives that answer and repurposes it to solve this modern problem. The test operates as follows: the jury is to accept the facts as the defendant in their delusional state believed them to exist. Accepting those facts as true, if the defendant would otherwise have an affirmative defense, the jury is required to acquit by reason of insanity. This instruction would be given before any other insanity instruction. After the jury performs this test, they would proceed to the jurisdiction’s usual insanity test. Requiring the jury to go through this preliminary step to any insanity defense ensures that defendants suffering from delusions are, at a bare minimum, treated equally before the law as everybody else.

To read this Note, please click here: Insanity Step Zero: A Modern Application of M’Naghten’s Question Four Test.