Recent Supreme Court Ruling Jeopardizes Protections for the Mentally Ill

In March 2020, the Supreme Court decided in a 6-3 decision that a Kansas law effectively eliminating the insanity defense complied with the due process clause (Kahler v. Kansas). Kansas, like five other states, only allows a defendant to plead not guilty on the grounds  of insanity or mental defect in very specific cases; the only way a defendant in Kansas can be found not guilty by reason of insanity is if they can prove to the jury that they did not realize their actions would result in the crime of which they are accused, removing the necessary criminal element of intent. In her  majority opinion, Justice Kagangives the example of an individual not understanding “the function of a gun or the consequences of its use” as meeting this narrow criteria. The Kansas law goes against the generally accepted notion of the insanity defense by only allowing one of the two prongs of the defense into court, this article will discuss the potential reverberations of this decision on mentally ill defendants across the country. 

The so-called “insanity defense” has a long, rich history in the United States. Originally adopted from the 1843 British M’Naghten rule, the insanity defense establishes a presumption of sanity at the time of the crime unless defendants are  able to prove that they either do not know what they are doing or believe that what they are doing is not morally or legally wrong. There is a very important distinction between these two elements- the first establishes criminal intent while the second focuses on culpability. The latter, in practice, usually takes the form of delusions that God or a prophet is commanding them to commit illegal actions, but can also happen when the defendant has a mental disability or other neurodivergent characteristic that prevents them from understanding the difference between legal and illegal actions. The M’Naghten Rule is still the standard in most states.

In the case of Kahler v. Kansas, James Kahler was charged with capital murder for the shooting deaths of four family members. Kahler and his lawyers claimed that the state’s negation of the moral or legal incapacity aspect of the insanity defense violated the due process clause because, under current Kansas law, defendants who cannot differentiate between right and wrong during the time of their alleged crime can still be convicted. The Supreme Court, however, disagreed. This ruling technically follows precedent; the Supreme Court has historically allowed states to interpret the insanity defense how they see fit, provided there is consideration of the defendant’s mental state at some point during the judicial process. In Kansas, this consideration takes place during sentencing, where defendants and their counsel are free to present any mitigating factors to the judge. Kahler and his legal team, however, claimed that this measure did not amount to sufficient due process during the trial.

In criminal trials, due process generally refers to the right to a trial before an impartial judge, the right to an attorney, the right to access competing evidence and present your own evidence, and the right to cross examine witnesses. Since the Kansas law still allows for the presentation of evidence relating to the mental state of the defendant while committing the crime, the Supreme Court reasoned that due process has been met, following the precedent set by prior case law allowing for a relatively wide application of the M’Naghten rule that is largely deferential to the individual state. However, the implications of this ruling can be far reaching. The Supreme Court has ruled on the scope of the insanity defense, but never explicitly confirmed a law in a state that allows for one of the prongs of the M’Naghten rule to be discarded during the trial phase. This opens the door for other states to follow suit, which could have negative repercussions for those suffering from severe mental illness. Although only time will tell, Justice Breyer raised this point in his dissent and cautioned the majority against doing just that, stating that upholding the Kansas law “runs contrary to a legal tradition that embodies a fundamental precept of our criminal law and that stretches back, at least, to the origins of our Nation.”