An attempt is made to locate excuses in the network of rules and principles governing criminal liability and to distinguish them from other grounds of exculpation, such as justification, in terms of their grounding in some disability of the defendant. Three categories of excuses allowed by the criminal law are surveyed: involuntariness, reasonable deficiency, and nonresponsibility. An examination of principles underlying the law's pattern of excuses suggests that notions of voluntarism, both literal and metaphoric, determine when blame is justified in ordinary moral discourse. A critical assessment is presented of the legal excuses in each category to determine how fully legal excuses conform to the requirements of just blaming. It is argued that the criminal law, in contrast to social mores, must serve as a clear, explicit guide to lawful conduct. It also must discourage the belief that a loophole can always be found to escape prosecution. Further, it must be suited to fair and uniform application and restrain as much as possible the biases of individual judges and jurors. Therefore, instead of permitting any excuse that the court deems relevant, the law defines the elements of legal excuses. It is the nature of such definitions that they cannot always accommodate subtle moral distinctions or novel situations. For these reasons, the law sacrifices complete accord between moral and legal excuses. 103 footnotes.