In Utah under the leadership of Brigham Young, Mormons retained and continued to develop all of the major political and theological innovations of the Nauvoo period, including temple worship, the second anointing, the blood atonement doctrine, the Council of Fifty, theocratic monarchy, and plural marriage. Brigham Young expanded upon Joseph's theological innovations with his own "Adam-God" doctrine. Young also revived the Nauvoo legion, as well as a group of "enforcers" consisting in large part of former Danites.

From 1856 to 1859, Utah Mormonism experienced a period of intense -- some Mormon historians have described it as "fanatical" -- revivalism. For most Mormons, the revivals served as an incentive to be baptized or re-baptized, renew their covenants, and make increased efforts to obey the commandments. The percentage of Mormons entering into plural marriages reached its highest level during these years. There was also widespread, fiery preaching of the doctrine of blood atonement, and a rash of vigilante murders that were fanned by this preaching. Some Mormon leaders (such as Hosea Stout, a former Danite and member of Joseph's Nauvoo "Night Watch"), also sought to enforce the blood atonement doctrine, invoking the authority of the Utah theocracy.

In 1857, the revival was given impetus when word reached Utah of an impending "invasion" by federal troops. As tensions rose and war hysteria spread, Mormons prepared to resist the invaders by force. Though ultimately there were no battle casualties in the "Utah War," a caravan of about 120 non-Mormons en route to California were massacred by Mormon militia at Mountain Meadows.

Though Mormons maintained the forms of American democratic government, throughout most of the nineteenth century 95% of Mormons voted for candidates who were vetted and presented to them by the Mormon hierarchy, and the territories were ruled by the priesthood. Even after Brigham Young was formally deposed as territorial governor in 1857, his "gentile" successors soon learned that they could accomplish nothing in the territory without the cooperation of the church leadership. This situation was considered intolerable by the rest of the nation, so for most of the remainder of the nineteenth century the Federal government was engaged in a protracted struggle with the Mormon Church to break the power of the theocracy.

Polygamy was viewed by the rest of the nation as an abomination, and became, in the eyes of the government, a symbol of the theocracy, so much of the struggle centered on efforts to eradicate "the principle." The Morrill Act (1862) criminalized bigamy in Federal territories, but was difficult to enforce because polygamous marriages often could not be proven. The Edmunds Act (1882) eliminated that problem by criminalizing "unlawful cohabitation," resulting in the imprisonment of an estimated 1,300 men. While, by one historian's estimate, only 20-40% of Mormon males and 30-55% of Mormon females during this period entered into polygamous marriages, almost 100% of the upper echelon of Mormon leadership were involved in polygamous relationships. The Edmunds Act had a devastating impact on the leadership, forcing them to go into hiding or to flee to polygamous colonies in Canada or Mexico. The Tucker Amendment in 1887 struck the final blow by dissolving the corporation of the Church of Jesus Christ of Latter-day Saints, and allowing the Federal government to seize church assets and property in excess of $50,000. In 1890, legislation to disfranchise Mormons was being considered when the hierarchy finally accepted defeat. In 1890 church president Wilford Woodruff issued the "Manifesto," formally ending polygamy.

The old Mormon theocracy was also quietly dismantled. John Taylor, who had spent most of his presidency in hiding, was the last Mormon prophet to be crowned "king on earth." There were no new appointments to the Council of Fifty, which held its last meeting in 1884. (Heber J. Grant, the last living member of the Council of Fifty, died in 1945.) More importantly, the church-controlled "People's Party" was disbanded in 1891, Mormons were encouraged to get involved in national partisan politics by becoming Democrats or Republicans, and the church leadership promised to stay politically neutral by refraining from making political pronouncements or attempting to sway church members at the polls.

For another brief on-line history of Mormon polygamy, and a list of books in print on the subject, see the Signature Books Library.