Michael Pasquier examines the "lived" religion of French missionaries in their daily encounters with anti-Catholic Protestants and anti-clerical Catholics on the American frontier. Focusing on the collective thoughts, feelings, and actions of priests who found themselves caught between the formal canonical standards of the church and the informal experiences of missionaries in American culture, Pasquier illuminates the historical intersection of American, French, and Roman interests in the United States. Several important conclusions emerge. Pasquier shows that the French missionaries were pivotal actors in the transition from English republican Catholicism of the 18th century to the multiethnic American Catholicism of the 19th. These missionaries lived, he shows, along a fluid spectrum of Catholicism that moved between a Romanized and an American church, neither of which existed in the rigid forms constructed by historians. He finds that at no point did French missionaries engage more directly in distinctively American affairs than in the religious debates surrounding slavery, secessions, and civil war. These issues, he shows, compelled even the most politically aloof missionaries to step out of the shadow of Rome and stake their church on the side of the Confederacy. In so doing, they set in motion a strain of Catholicism more amenable to Southern concepts of social conservatism, paternalism, and white supremacy, and strikingly different from the liberal, progressive strain that historians have usually highlighted.