At stake is our basic understanding of the difference between right and wrong. If someone commits a wrongful act but, due to a mental illness or defect, wasn’t able to recognize that what they were doing was wrong, we don’t consider them to have committed a crime.
The same goes for people who are completely unable to conform their behavior to the law. If their mental illness or defect meant that they couldn’t keep themselves from breaking the law, they have traditionally been considered not guilty.
Can a state change those traditional rules? In 1995, the state of Kansas decided to get rid of part of the insanity defense. It’s still a defense in Kansas to say that you couldn’t recognize that your behavior was wrong. No longer, however, could you legally argue that you could not conform your behavior to the law.
Think of it this way, as Justice Stephen Breyer suggested during oral arguments earlier this month. Imagine there are two defendants, each of whom killed someone. The first defendant did so because his mental illness led him to believe he was killing a dog. The second did so because a dog ordered him to kill and his mental illness prevented him from resisting that order.
Assuming their claims were true, each would traditionally be protected by the insanity defense. Kansas changed the law so that the second defendant no longer is.
A tragic case could lead to legal clarification
A man who was convicted of killing his wife and children appealed his conviction after he was denied access to the insanity defense. He alleged that his mental illnesses prevented him from being able to stop himself. His lawyers argued that Kansas’s attempt to deny him access to the insanity defense violates the U.S. Constitution’s Due Process and Cruel and Unusual Punishment clauses.
Some of the Justices pointed out that the defendant had a relatively weak claim for the insanity defense. They might rule that Kansas’s reformulation of the insanity defense is unconstitutional but not allow this particular defendant to use it.
The defense argued that there is simply a bar beneath which states cannot go. They can’t change the fundamental formulation of criminal responsibility. They pointed to centuries of history leading back to the English common law that allowed both types of insanity defenses.
Kansas, backed by the U.S. Department of Justice, argued that no single formulation of the insanity defense was indisputably lodged in our history. They urged the Justices to leave the question to the states.
According to the defendant’s lawyer, the insanity defense is invoked in fewer than 1% of murder cases. It is successful in only a quarter of those cases.
