The Supreme Court ruled Monday that states can eliminate the traditional insanity defense. Only four states don’t have one in the U.S., and three of those are in the Mountain West.
In most states, defendants can plead “not guilty by reason of insanity.” In Kansas, Utah, Montana and Idaho, though, defendants haven’t been able to for decades. That plea is extremely rare and difficult, but these four states, especially, were still concerned about abuse.
You still can’t be convicted if you didn’t know you were committing a crime in those states (like if you think you’re flying a kite instead of committing that crime). But if you understand that what you did was illegal, you could still be found guilty, even if mental illness affected your ability to know the difference between right and wrong.
One man in Kansas challenged the states’ decisions to scrap their insanity defense, saying he should be able to use it. He was charged with murdering his ex-wife, her mother and his two teenage daughters. He let his young son go free – the one he liked the most.
The court disagreed, and in a 6-3 opinion, said it’s up to the states whether they have a traditional insanity defense.
Shaakirrah Sanders is a law professor and constitutional scholar at the University of Idaho. She said the court’s decision in Kahler v. Kansas was very narrow.
“What this case says is that on the large scale you don’t have to offer [the insanity defense], but in an individualized circumstance, you may want to think about it,” Sanders said. “A lot of the court’s reasoning is this historic trend of allowing states autonomy on the question of their criminal law and procedure.”
The issue could make its way to the Supreme Court again under different circumstances, Sanders explained. Since this case focused on due process rights, she said another plaintiff could argue a lack of traditional insanity defence violates their eighth amendment rights, or constitutes cruel and unusual punishment.
In Utah, a bill that would have reintroduced the traditional insanity defense died earlier this month.
Find reporter Madelyn Beck on Twitter @MadelynBeck8
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This story was produced by the Mountain West News Bureau, a collaboration between Wyoming Public Media, Boise State Public Radio in Idaho, KUER in Salt Lake City, KUNR in Nevada, the O’Connor Center for the Rocky Mountain West in Montana, and KRCC and KUNC in Colorado.