This dissertation seeks to broaden political theorists' understanding of political Hebraism, arguing that Thomas Aquinas should be regarded as an important precursor to this school of thought. Viewing Aquinas in such a role has two effects. First and foremost, it reasserts the importance of Aquinas's reflections on the Mosaic Law, or Old Law, for a complete understanding of his political thought. While these writings remain understudied, they are rich with implications for political theory and practice. I argue that the Mosaic Law, for Aquinas, is a divinely-given law that is also perfectly reconcilable with the demands of reason, and that it is the exemplary case of "human law" insofar as it directs a particular community toward its common good. Examining Aquinas's treatment of the regime of the Hebrews provides an avenue into the understanding of his views regarding the two-fold end of political community, the virtues of prudence and particularity, the best constitution and laws, and citizenship. In order to understand more fully Aquinas's political thought, we must give his discussion of the Mosaic Law the attention it deserves. Equally important is the second aim of this project: to argue that Aquinas can enrich contemporary discussion of political Hebraism. Recent studies of this subject have focused on early modern use of the Hebrew Bible and Old Testament as a model for politics by key thinkers such as Hobbes, Locke, and John Selden. This dissertation argues that Aquinas deserves a place in the growing body of scholarship on political Hebraism, since the fundamental idea that gained prominence with political Hebraists during the early modern period—that the Hebrew constitution should be viewed as a standard and model for constitutions in general—is already present in Aquinas's writings on law. Through a comparison between Aquinas and Selden, identifying both continuities and discontinuities in their approaches to the Hebrew political model, I am aim to shed light on the wider issue of the relationship between medieval and modern political thought.