Insanity Defence

The ethical strains of mental illness as a defence to criminal behavior.

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I would like to begin by wishing everyone reading this a Happy Thanksgiving. Wishing you all a joyous day of eating, family, and gratefulness.

In the United States legal system there exists a term called the insanity defence. Insanity defense is something that a defendant pleads that admits to the crime however removes the criminal aspect of the action. In other words, if pleaded the insanity defence can excuse the defendant from the crime they had committed on the grounds that they lacked the mens rea (look at mens rea blog) that would convict them. This clearly is a topic of discussion as insanity defence would completely excuse a crime solely on the grounds of the defendants “not knowing what he was doing”. This blog aims to explain mens rea in its full capacity and the ethical constraints of insanity defense. 

As previously stated, insanity defence is when a defendant admits to a crime but denies mens rea thus removing the criminal charges against them. There are several tests that are used to determine whether or not a defendant is worthy of earning an insanity defense plea. Out of these several tests, there are four that are most vital in determining insanity defence. The first essential test is the M’Naghten Rule, named after Daniel M’Naghten who killed a high ranking official. The M’Naghten Rules questions if the defendant knew what they were doing at the time the crime was committed. If it is

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deemed so, the defendant is labeled as legally insane. The second of the essential tests is the "Irresistible Impulse” test, often used along with the M’Naghten Rule. The "Irresistible Impulse” test focuses on if the defendant’s mental health had caused the defendant to commit the crime while aware that what they were doing was a criminal action. The third of the essential tests is the Durham Rule, used only in the state of New Hampshire. The Durham Rule focuses on a psychologist's diagnosis on the whether or not the defendant may be deemed insane. This has come out of practice as psychologists may disagree amongst themselves about a defendant's mental state. Finally, the fourth of the essential test is determining metal state via the Model Penal Code. The Model Penal Code has a more loose definition of what deems one as insane, but includes certain flaws in other tests as well as prevents psychopaths and sociopaths from earning the insanity defence plea. 

An instance of insanity defense in trial can be seen in McElrath v. Georgia, argued in 2023. Damian McElrath suffered from mental health issues at the time of the crime. He was charged with three felonies: malice murder, aggravated assault, and felony murder after the crime of murder. He had pleaded an insanity defense which was accepted by the court for his malice murder charge, but then dined for the other charges. The state court disagreed with the verdicts claiming they were incompatible with each other, and thus ordered for a retrial on all charges. The court had deemed the retrial unlawful as per the Dobble Jeperdey section of the Fifth Amendment, but retail was later permitted by the Supreme Court. In short, insanity defense is seen in courts to this date. 

While the insanity plea does exist and is used in courts as an “excuse ” to this date, it is extremely ethically uncertain. The overall concept of insanity defense is that the defendant “did not know what they were doing” and thus should be excused from the criminal office they had committed. In that logic, crimes committed during intoxication should have their own plea that is put into common use. While there does exist an intoxication plea, it is not in common use as intoxication is self induced but mental health is not. What must be kept in mind was that a crime was still committed. If a man, such as Damian McElrath, kills another and is granted insanity defense the crime loses its weight. At the end of the day, anyone can earn insanity defense as long as they appear outwardly "insane" (with the exception of whenever the Durham Rule test is being given). In short, the “insane” should not be excused of a crime as the crime was still committed. 

Sources:

TLD Staff, “The Four Tests Used for Determining Legal Insanity.”, The Law Dictionary, 19 Nov 2024, http://thelawdictionary.org/article/four-tests-used-determining-legal-insanity/.

“Insanity defense.” Legal Information Institute, June 2023, https://www.law.cornell.edu/wex/insanity_defense.

McElrath v. Georgia, 601 U.S. ___ (2024)