This project seeks to understand and to bring into dialogue two ideas of sovereignty in western thought, one rooted in the Augustinian tradition of politics and connected historically with the period from the Middle Ages through the Reformation era, the other from the era of the Thirty Years War to the present and identified with the state system of international order associated with the Peace of Westphalia. In the former sovereignty is a moral concept pertaining to the person who exercises sovereign authority; it defines sovereignty in terms of the responsibility of ensuring the common good as understood in Augustinian thought--the maintenance of a common order characterized by justice and thus by peace. In the latter sovereignty is a quality of the state; amoral in content, its central feature is to define sovereignty in terms of maintaining territorial integrity and state security against external threats. Recently the Westphalian conception has come under stress, being challenged by the idea that rulers who engage in gross human rights abuses against their people thereby lose their claim to the protections of sovereignty and may be deposed and/or brought to justice. These challenges are based on essentially moral claims recalling the earlier conception of sovereignty in terms of responsibilities. Yet so far the critique of the Westphalian idea has not formally engaged this moral idea of sovereignty or examined how a new theoretical understanding of sovereignty incorporating elements of the earlier conception might look. This project aims, first, to recover the older moral concept of sovereignty in religious and secular political thought from the medieval and early modern periods, and second, to bring it into critical dialogue with the Westphalian idea so as to suggest a revised understanding of sovereignty building on the strengths of both these historical concepts.