Reflecting the attention Parsons gave to religion in relation to modernity, this paper reinterprets the significance of the Puritan ethic in modern America. It is first argued that a crucial feature of the Reformation was the Calvinist collapse of the traditional separation of the religious and mundane spheres, which makes sacralization of the mundane as likely as secularization of the religious; a second feature was that Puritanism stresses a sharp break between members of the community and outsiders, legitimating callous or harsh treatment of the latter. The paper relates these features to two themes of importance in the development of America imprinted by a Puritan culture: “service,” which Parsons early gave attention to, and “mission.” Three sorts of mission are noted, beyond the initial religious one: (a) establishing a free polity, (b) harnessing the forces of nature via technology, (c) bringing a pax Americana to the world as an extension of the American covenant.