This book traces the connections between diverging postwar European integration policies and intra-Christian divisions to argue that supranational integration originates from Roman Catholic internationalism, and that resistance to integration, conversely, is based in Protestantism. Royce supports this thesis through a rigorously supported historical narrative, arguing that sixteenth-century theological conflicts generated seventeenth-century constitutional solutions, which ultimately effected the political choices both for and against integration during the twentieth century....