In the wake of 9/11, postsecularism has emerged as a capacious critical perspective that challenges the historical narrative of Enlightenment secularization. Postsecular critique observes the persistence of religion in modernity and connects its persistence to historical religion as a longer and unbroken narrative of national, cultural, and legal discourses. Drawing on intellectual history, the anthropology of religion, and New England colonial historiography, this essay argues that our contemporary understanding of the United States is deepened by rereading the nation’s puritan past from a postsecular perspective. The essay considers the travails of Roger Williams, the Antinomian Controversy, and the puritan treatment of the early Quakers as important contributions to American perspectives on the separation of church and state, the role of spirituality in the secular, and the legal and procedural application of “tolerance.”