Much has been written of John Courtney Murray’s reception of Thomas Aquinas. Although not totally misplaced, this near-exclusive attention to Aquinas’s role in Murray’s thought has obscured the contributions of an equally important figure—Augustine of Hippo—to Murray’s political theology. This article thus offers a novel survey of Murray’s seminal We Hold These Truths and reveals that Augustine’s theory of Divine Providence, as articulated in The City of God, circumscribed Murray’s Thomism. With the hope of reconciling differences between American Catholics and non-Catholics at mid-century, Murray relied upon two of the most influential theologians in western Christianity to assert that Divine Providence led the Founding Fathers to place the natural law and religious liberty at the foundation of the American republic.