Opinion of the Court, Kahler vs. Kansas, March 23, 2020This case is about Kansas’s treatment of a criminal defendant’s insanity claim. In Kansas, a defendant can invoke mental illness to show that he lacked the requisite mens rea (intent) for a crime. He can also raise mental illness after conviction to justify either a reduced term of imprisonment or commitment to a mental health facility. But Kansas, unlike many States, will not wholly exonerate a defendant on the ground that his illness prevented him from recognizing his criminal act as morally wrong. The issue here is whether the Constitution’s Due Process Clause forces Kansas to do so—otherwise said, whether that Clause compels the acquittal of any defendant who, because of mental illness, could not tell right from wrong when committing his crime. We hold that the Clause imposes no such requirement.