Abstract: This study examines how a rational reconstruction of certain aspects of the works of St. Augustine of Hippo and St. Thomas Aquinas may shed critical light on contemporary debates over the ethical purposes of public law. It focuses on how law may shape the ethical sensibilities of individuals by providing them with reasons for action. It addresses this issue by considering each figure's proposals about public law in the light of his account of how individuals are formed as moral agents. Each thinker's account of ethical formation clarifies the conditions under which coercive public norms may be taken as ethically valuable reasons for action rather than merely coercive ones. The inquiry involves three main questions. First, how does each thinker's theological anthropology situate the role of public law in the human drama of moving from deficiency and deformity to perfection? Second, how does each theologian expect the claims of public law to be recognized and internalized by individual citizens in away that enhances the virtues? Third, in what way, if at all, may each thinker's account of these issues be brought into critical accord with the general norm of respect for individual liberty and self-determination that figures so prominently in modern ethics? Chapters one through four argue that Aquinas's discussion of public law and virtue in the Summa theologiae partially elaborates a conception of the conditions of receptivity under which law may provide ethically valuable reasons for action. His discussion of the virtue of obedience (Ilallae.104.3.2) and his account of obeying law 'from the mere dictates of reason' (lallae.92.1.2) suggest a conception of recognition that provides the operative link between coercive public norms and the ethical sensibilities of individuals. This perspective provides the rudiments of a conception of legal perfectionism that opposes both natural law conservativism and modern liberal Thomism. Chapters five and six juxtapose this interpretation of Aquinas with contemporary Augustinian positions that oppose legal perfectionism. These chapters claim that Augustine's famous defense of religious coercion and his conception of ethical formation in De trinitate offer a position more amenable to perfectionism than is often claimed.