In Part IV (Chapters 12–15) the final case study of this book explores the relationship between right-wing populism and religion in the USA. It begins in Chapter 12 by discussing the historical background of the First Amendment, American civil religion, and the country’s history of white Christian nationalism and religious culture wars. Specifically, Chapter 12 shows how America’s civil religious tradition had historically been able to act as an important source of integration and prophetic criticism in American politics in spite of repeated challenges from white Christian nationalism on the one hand and secularist tendencies on the other. However, this chapter also explores how this integrative potential has been profoundly challenged by the rise of a new secular identity cleavage that increasingly superseded America’s old religious culture wars and prepared the grounds for the right-wing populist and identitarian politics of Donald Trump.