After distinguishing different types of Legal Moralism (positive/negative; modest/ ambitious) I defend a modest, positive Legal Moralism: we have good reason to criminalize a type of conduct if and only if it constitutes a public wrong. Some of the central elements of the argument will be: the need to begin not (as many Legal Moralists begin) with the entire realm of moral wrongdoing, but with conduct falling within the public realm of civic life; the significance of the various different processes of criminalization (of which legislation is only one); and the need to attend to the relationship between criminal law and other modes of legal regulation. Criminal law focuses on wrongs: it identifies a set of public wrongs, and provides for tho...