The Insanity Defense

How One Case Could Change The Justice System's Approach


By Sarah Rogers

With a number of controversial cases on the docket, the Supreme Court kicked off on October 7th receiving arguments for Kahler v. Kansas -- an accused’s rights case centered around the “insanity defense.”[1] In 2009, James Kahler was sentenced to death for the brutal killings of his wife, their teenage daughters, and his wife’s grandmother. At trial, his lawyers constructed a defense plan on the basis that Kahler suffered from severe mental illnesses -- mainly depression, as well as a number of personality disorders. [2]However, under Kansas law they were restricted to arguing that these illnesses precluded Kahler from having criminal intent -- but because he still knew he was killing another human being, he was guilty. This is a remarkable anomaly in that practically every other state considers the “insanity defense” an affirmative offense. It is broadly accepted that an individual whose mental disorder prevents them from distinguishing right from wrong cannot be held criminally liable for their actions, even if they are proven guilty. This interpretation of law dates back to the 19th century and was universally recognized throughout the U.S. until the end of the 20th century, following a series of highly-publicized cases.[3] Particularly influential was the case of John Hinckley, who in 1981 shot President Ronald Reagan and three others, but was found not guilty by reason of insanity.[4] Following Hinckley’s acquittal, the public began to doubt the legitimacy of mental-capacity defenses, and four states -- including Kansas -- eliminated the insanity defense.


Today, Kansas solely permits the “mental-illness defense” -- allowing evidence of mental disorders only to the extent where they impede the defendant’s ability to be aware of their actions.[5] However, mental illnesses rarely prevent people from knowing what they are doing; far more often, they give people wildly irrational reasons for unlawful activity. In drawing a distinction between these two things, and only protecting the former, Kansas law deeply misunderstands the practical wisdom on which the traditional test of insanity was founded. Justice Breyer put this perfectly during the hearing: “One defendant kills a victim he thinks is a god. The second defendant knows it’s a person but thinks the dog told him to do it. They are both crazy. And why does Kansas say one is guilty, the other is not guilty?”


Up until now, the Supreme Court had never been asked to consider whether states may eliminate such fundamental principles of law. Yet, despite the Court’s typical wariness of imposing restrictions on states’ governance of criminal proceedings, it has a long-established practice of fortifying traditional legal doctrines.[6] Thus, in deciding for the first time whether abolishing the insanity defense is a constitutional violation, the Supreme Court will set significant precedent on the role of the Federal government in upholding long-established legal customs in America. Moreover, it will also have a crucial stake in the fate of legal protections for the mentally ill nationwide. If the court decides in favor of Kansas, states will be given an open invitation to begin loosening legal practices that encourage non-carceral dispositions for the mentally ill. The resulting criminalization of mental illness would not only affect those suffering from personality disorders like depression, but also those suffering from addiction to drugs and other substances. Treating mental illness as though it were a crime itself is a slippery slope to using incarceration as the solution to every problem that society does not know how to solve. Even worse, it is a definitive way to ensure that those who need help the most are deprived of it.


Of course, Supreme Court decisions are generally founded on far more than merely “doing the right thing”. Yet, in this case the insanity defense is a morally just course of action backed by long-established and deeply embedded American legal precedent. In the vast majority of jurisdictions, legally “insane” individuals who commit even the most heinous of crimes are put in secure non-penal institutions for treatment. These patients are kept in custody or under community supervision until a court deems that they are no longer a danger to society. This system has worked for centuries providing treatment to the ill as opposed to incarcerating them for crimes they cannot possibly understand: so why should Kansas be any different?


         The overarching purpose of incarceration is to provide rehabilitation for those found guilty of serious offenses. Yet, if one’s reasoning for committing a crime is blurred by mental illness, which leaves them incapable of distinguishing right from wrong, then sentencing them to prison fundamentally misunderstands what the carceral system was built to do. Prisons were never intended to treat mental disorders, nor were they meant to hold people indefinitely, because of a lack of a better place to put them. Indeed, the mentally ill who commit violent crime pose a threat to public safety and should not remain in society untouched; but for them to achieve rehabilitation, they must be provided with treatment, not punishment. Thus, the insanity defense is not only morally just, but a pragmatic necessity. For if someone is truly so ill that they are incapable of basic moral judgement, then they ought to receive actual treatment, not to be put in a cell where the system locks them up and throws away the key.  


[1] SCOTUSblog. Kahler v. Kansas

[2] Morse, Stephen and Bonnie, Richard. “Insanity and the Supreme Court.” WSJ. 6 Oct. 2019.

[3] Black, Robert. “Kahaler v. Kansas: Can States Abolish the Insanity Defense?” National Constitutional Center. 8 Oct. 2019

[4] CNN Library. “John Hinckley Jr Fast Facts.” CNN. 11 Sept. 2019.

[5] Epps, Garrett. “Does the Constitution Guarantee a Right to an Insanity Defense?” The Atlantic. 6 Oct, 2019.

[6] Bravin, Jess. “Supreme Court Opens Term with Look at Kansas’ Effort to Bar Insanity Defense.” WSJ. 7 Oct. 2019.