On April 6th, 1917, one Reed Owen Smoot prayed for aid in troubled times. That is hardly original in itself. The scene would thus be unworthy of note if it were not for further specifics. April 6th, 1917, was the day on which the United States declared war on Germany and entered the conflict now known as World War I. The prayer was offered in the US Senate in response to that decision. But just as significant as the setting is the praying subject. Smoot was a Senator from Utah, a Republican, and an Apostle of the Church of Jesus Christ of Latter-Day Saints (LDS), that is a Mormon. To which the average reader likely responds, “of course.” If Smoot was from Utah, he was of course Mormon, of course Republican, and of course willing to perform religiosity in public. This essay does not aim to cut through that chain of assumptions. Rather, my discussion offers an account of how these links have been forged: a development that would have surprised the majority of nineteenth-century Mormons as much as their non-Mormon contemporaries. What could be conservative about open scriptural canon, communitarian utopianism, and non-monogamous marriage? Ultimately, however, Mormon conservatism is grounded in particulars of that theology. It has further been shaped, gradually but thereby durably, through shifting principles of LDS political engagement. Consideration of this process offers a case study in how an initially radical formation can fashion itself into conservatism.