Nelsen and Guth contend that religion, or "confessional culture," plays a powerful role in shaping European ideas about politics, attitudes toward European integration, and national and continental identities in its leaders and citizens. Catholicism has for centuries promoted the unity of Christendom, while Protestantism has valued particularity and feared Catholic dominance. These confessional cultures, the authors argue, have resulted in two very different visions of Europe that have deeply influenced the process of postwar integration. Catholics have seen Europe as a single cultural entity that is best governed by a single polity; Protestants have never felt part of continental culture and have valued national borders as protectors of liberties historically threatened by Catholic powers. Catholics have pressed for a politically united Europe; Protestants have resisted sacrificing sovereignty to federal institutions, favoring pragmatic cooperation. Despite growing secularization of the continent, not to mention the impact of Islam, confessional culture still exerts enormous influence. And, the authors conclude, European elites must recognize the enduring significance of this Catholic-Protestant cultural divide as the EU attempts to solve its social and economic and political crises.