Nineteenth-century America saw a nationwide campaign to tame the “Mormon menace.” Promoted by an alliance of religious and secular individuals, institutions, and ideals, it even led President Rutherford B. Hayes to recommend stripping Mormons of their citizenship. Although Contending Modernities will focus primarily on Mormonism’s fellow subjects of modern opprobrium—Islam and Catholicism—it is important to consider such other “shadow cases” as we examine the complex dynamics of religion in modernity. The deep pluralism characteristic of the modern age has posed, and will continue to pose, a substantial challenge to the largely Euro-American-Protestant construct of secularism that dominated much of the nineteenth and twentieth centuries.