Since the promulgation of the United States’ Constitution in 1788, Protestants across denominational lines largely supported disestablishment and the Constitution’s provision for religious liberty in Article I. Last week I noted that there was in the Early Republic significant debate over how expansive religious liberty was. In New England in particular, Congregationalist and Unitarian ministers conceived of religious liberty as a corporatist right, not as an individual freedom per se. But even the corporatist reading of religious liberty did not, in the opinion of Protestant clergymen as late as the beginning of the Twentieth Century, mean that any religious could be publicly practiced in the United States.
Beginning in the 1830s treatment of the Latter Day Saint movement presented a problem for proponents of societal Christianization as well as politicians and intellectuals who wanted an expansive reading of the First Amendment. Among the most vociferous opponents of Mormonism in public life were conservative Protestants. Throughout the Nineteenth Century, many Presbyterians in particular routinely took the side of secular authority in order to preclude the rise of what they believed was a pagan theocracy hidden behind a faux Christian mantle. As late as 1911 Samuel Ellis Wishard, a Presbyterian minister in Utah, said the election of Reed Smoot—a Mormon apostle—to the US Senate in 1903 filled him with shame and dismay. There seems to have been no statutory or constitutional provision Wishard could point to other than an inference that Smoot’s religion somehow disqualified him for service in the senate. Wishard also argued that Smoot could not be a good Mormon and a law-abiding US citizen and senator. The argument prefigured Protestant treatment of John Kennedy six decades later.
Mormon flaunting of federal authority also figured in to Wishard’s complaints. Brigham Young’s flaunting of federal law, rhetorical anathematization of government statutes, and denunciations of federal officials disgusted the Presbyterian divine and provided evidence of Mormon evil, he believed, for all the world to freely observe. E.O Guerrant, another Presbyterian, argued that the Latter Day Saints’ creed taught “disloyalty to all civil government” and like Wishard argued that their reasons for hedging loyalty to the U.S. government came more from an innate desire to hide practices society deemed deplorable by broader society and less from meaningful theological conviction. Both Wishard and Guerrant warned repeatedly of theocracy, which they believed Latter Day Saints had set up and which they warned had no place in the American order.
Protestant treatment of Latter Day Saints presents a conundrum for champions of secularism and for champions of a specifically Christianized America. There was not, and is not, a statutory mechanism in the United States constitutional apparatus that preserves or perpetuates a specific type of Protestant morality in the United States. Mormonism’s sins seem to have been against established social mores and folkways rather than the Constitution itself. But the Constitution didn’t (and doesn’t) protect American society from theological innovation. Nineteenth Century Mormonism was, as Spencer Fluhman noted, thoroughly entangled with Protestantism and yet something distinctly other; the same can be said for aspects of modern Pentecostalism. Protestants in the Nineteenth Century were comfortable with persecution of the former; some Twenty-First Century Protestants make common cause with the latter for political purposes. The difference seems to be that, unlike populist and folk-influenced modern Evangelicals, Nineteenth Century Protestants believed that the secular American political order was wedded to a profoundly religious social order, and that American religiosity was profoundly secular in its socio-political commitments. That which was secular was Christian, and that which was Christian was secular. 
 Samuel Ellis Wishard, The Mormons (New York City: Presbyterian Home Missions, 1904), 116-19; E.O. Guerrant, The Mormons (Richmond, VA: Presbyterian Committee on Publication, 1899), 9.
 Spencer Fluhman, “A Peculiar People”: Anti-Mormonism and the Making of Religion in Nineteenth America (Chapel Hill: University of North Carolina Press, 2012), 3-12