Kahler, charged with capital murder after he killed four family members, unsuccessfully argued that Kansas's insanity defense violated due process because it permits the conviction of a defendant whose mental illness prevented him from distinguishing right from wrong. Convicted, Kahler was sentenced to death. The Supreme Court affirmed. Due process does not require Kansas to adopt an insanity test that turns on a defendant's ability to recognize that his crime was morally wrong. A state rule about criminal liability violates due process only if it "offends some principle of justice so rooted in the traditions and conscience our people as to be ranked as fundamental." Early common law reveals no consensus favoring Kahler's approach. The tapestry of approaches adopted by the states indicates that no version of the insanity defense has become so ingrained in American law as to be "fundamental." The defense sits at the juncture of medical views of mental illness and moral and legal theories of criminal culpabilityareas of conflict and change--and is a matter for state governance, not constitutional law. Sim[lify