Jon Gjerde saw the nation’s encounter with Catholicism in the nineteenth century as the first of many encounters with religious minorities, particularly with those groups that arrived in the massive waves of migration in the early and late twentieth century. Indeed, one could easily substitute “Judaism,” “Hinduism,” “Buddhism,” or “Islam” for “Catholicism” and advance the century in his title. Moreover, the many conflicts that have emerged between minority and majority faiths, like the debates between nineteenth-century Catholics and Protestants, have rarely come to any clear resolution but instead play a profound role in shaping the economy, society, and politics of the United States. In short, religion continues to constitute a vital component, both divisive and constitutive, of American life in the modern age.