Psychopaths pose a challenge to those who make claims about the strength of moral assessments. These individuals are entirely unmoved by the moral rules that they articulate and purportedly espouse. Psychopaths appear rationally intact but are emotionally broken. In some cases, they commit horrendous crimes yet show no guilt, no remorse. Sentimentalists claim that the empirical evidence about psychopaths’ affective deficits supports that moral judgment is rooted in emotion and that psychopaths do not make genuine moral judgments—they can’t. Here, I challenge an explanation of psychopathy that indicts psychopaths’ emotional impairments alone. I conclude that there are rational requirements for moral motivation and that psychological and neuroscientific research support that psychopaths do not make the grade.