Our legal understanding of mental illness shouldn’t be restricted to a 19th-century precedent.
The Supreme Court is back in session today. And in this mad political season, it somehow seems fitting that one of the first cases it will consider is whether it is constitutional for a state to punish a person who cannot tell right from wrong because of mental illness.
On the surface, the question seems like one with obvious liberal and conservative answers: liberals, it would appear, should think that the Constitution protects people with certain serious forms of mental disability, whereas conservatives should think that states may be as harsh as they like in defining crime. And indeed, it seems probable that the court will split roughly on ideological lines in the case, Kahler v. Kansas.
But on closer examination, there is actually a strong liberal argument that the Constitution should be interpreted to allow states to define the relationship between crime, moral culpability, and mental health disorders. Our collective ideas about these extremely complicated issues are ever-changing, and must frequently be updated in the light of new mores and new science. To freeze the legal definition of what lawyers still call “insanity” based on a rule developed in the 19th century might help some defendants, but it doesn’t necessarily serve the overarching value of a living Constitution that allows the law to change with time.
The case involves a law that Kansas passed specifically in order to repudiate the traditional legal standard that most states use to handle cases where a defendant pleads insanity. The prevalent standard in the U.S. today is the so-called M’Naghten rule, named for a British case decided by the House of Lords in 1843. Under the M’Naghten test, as applied in Kansas before the change in laws, a jury could find the defendant not guilty by reason of insanity if the defendant “does not know the nature and quality of his act” or alternatively “does not know right from wrong with respect to that act.”
In its simplest form, the M’Naghten test absolves the defendant the criminal responsibility if he or she didn’t know it was wrong to commit the crime.
Kansas changed its law in 1996 to say that whether the defendant knew right from wrong was no longer relevant. Instead, under the law as it was in force when James Kahler killed his wife, his wife’s grandmother, and his two daughters, the only mental disease or defect defense available was if the defendant “lacked the mental state required as an element of the offense charged.”
What that meant in practice was that Kahler couldn’t be found not guilty by reason of insanity even if he could prove he didn’t know it was wrong to kill his family members when he did it. The only way he could raise a defense based on mental disease or defect was if he could prove that he didn’t know he was engaged in an act of killing at all. Kahler had been heard saying the words “I am going to kill her,” so he couldn’t prove that he lacked the mental capacity to form the intention to kill.
We have a hint about how some of the liberal justices might view this case. In 2012, a case from Idaho was brought to the Supreme Court challenging a similar law. The court declined to take that case, but Justice Stephen Breyer dissented from the decision to deny a hearing, and he was joined by Justices Ruth Bader Ginsburg and Sonia Sotomayor. Breyer noted at the time that the American Psychiatric Association and other friends of the court had pointed out that “seriously mentally ill individuals often … know that the victim is a human being, but due to mental illness, such as a paranoid delusion, they wrongly believe the act is justified.”
The only way for the Court to hold in favor of Kahler is for it to say that the Constitution, through the due process clause of the 14th Amendment (or conceivably through the Eighth Amendment’s ban on cruel and unusual punishment), requires that states preserve something like the M’Naghten rule. You can see why liberals might reach this conclusion: it would afford a baseline constitutional protection to defendants with certain illnesses, and states would not be allowed to offer less protection, as Kansas and Idaho have done.
Yet this appealing impulse would come at the expense of reading the Constitution to prohibit states from adopting new theories of how criminal liability should interact with mental health or disability. In the 1950s and 1960s, the M’Naghten test was itself subject to harsh criticism, and many authorities, including the authors of the Model Penal Code, preferred a different test that asked not about right and wrong but about whether a defendant had “substantial capacity to control” his or her behavior.
It seems extremely likely that, as our scientific understanding of the brain improves, and as our moral intuitions change, we will collectively adopt new views of when and how punishment is appropriate for people with varying kinds of cognitive, emotional, and intellectual conditions.
Liberals should be concerned about a constitutional holding that requires the M’Naghten rule. Today such a rule might seem like a baseline protection for defendants. But future generations might actually think that it is a basic mistake for the Constitution to require courts to ask a 19th century-style question about the supposed moral capacity to distinguish right from wrong.
A living Constitution not only evolves; it leaves room for state laws to evolve and change, too. This is an extremely hard case, but liberals shouldn’t assume it has only one right answer.