This chapter examines the mid twentieth-century convergence of Cold War liberalism and American Catholicism through the figure of foreign policy intellectual William Pfaff. In the 1940s and 1950s, Pfaff’s formative experiences occurred at the University of Notre Dame and at The Commonweal, a liberal Catholic journal of ideas, just as Catholic thought was opening decisively toward liberal modernity and, more specifically, embracing the United States as an anti-communist bulwark. By enlisting to fight in the Korean War and then joining the Free Europe Committee, Pfaff demonstrated his dedication to the American state’s hegemonic project, which he equated with Catholic anti-totalitarianism. Over the course of the 1960s, American engagement in the Vietnam War shook Pfaff’s faith in the liberalism that had allowed him to temporarily reconcile his Catholic and American identities. His increasingly idiosyncratic criticisms of U.S. empire in the decades that followed can be read as a refusal to equate American foreign policy with a particularly Catholic vision of liberal values, thus demonstrating the contingent nature of Catholic support for liberal imperialism.