By then, the practice of plural marriage had expanded beyond Joseph Smith's inner circle, and word of it had been passed by non-Mormon emigrants passing through Utah, where the evidence was in plain view. "During the first few years after their arrival in Utah," writes Young biographer M. R. Werner, "the fact that the Mormons practiced polygamy was an open secret."
The Mormons' embrace of plural marriage was based on a revelation that Smith said he had received. (It was written down in 1843, but most historians agree that Smith had begun taking multiple wives earlier.) With the example of polygamous biblical patriarchs such as Abraham and Jacob in mind, Smith concluded that "the possession of more than one wife was not only permissible, but actually necessary for complete salvation," Werner writes. Brigham Young, who took his first plural wife in 1842, after 18 years of monogamy, maintained that he had been a reluctant convert: "I was not desirous of shrinking from any duty, nor of failing in the least to do as I was commanded," he wrote in a reminiscence that would be collected in the church compendium Journal of Discourses, "but it was the first time in my life that I had desired the grave." (By the time he died, at age 76 in 1877, he had taken 55 wives but shared no "earthly life" with 30 of them, according to Arrington.) For years Young and other church leaders had dismissed allegations of plural marriages as calumnies circulated by enemies, but by the early 1850s, such denials were no longer plausible.
On August 29, 1852, at a general conference of Mormons in Salt Lake City, the church leadership publicly acknowledged plural marriage for the first time. Orson Pratt, a member of the Quorum of the Twelve Apostles, delivered a lengthy discourse, inviting the members to "look upon Abraham's blessings as your own, for the Lord blessed him with a promise of seed as numerous as the sand upon the seashore." After Pratt finished, Young read aloud Smith's revelation on plural marriage.
The disclosure was widely reported outside the church, and the effect was to quash any hopes the Utah Territory might have had for statehood under Young's leadership. And conflicts between Young's roles as governor of the territory and president of the church would only become more complicated.
In April 1855, at the Mormons' spring conference, Young called on some 160 men to abandon home, farm and family and head into the wilderness surrounding the Utah settlements to establish missions among the Native Americans there.
In Mormon cosmology, Indians were the descendants of a fallen ancient patriarch, and church officials said they were undertaking the missions to convert tribes on their borders to their faith and to improve their welfare. But Garland Hurt, recently arrived in Utah as an Indian agent, was suspicious. In a confidential letter to the head of the Bureau of Indian Affairs in Washington, he wrote that the missions were actually intended to teach the Indians to distinguish between "Mormons" and "Americans"—a distinction, he added, that would be "prejudicial to the interests of the latter." The few historians who have studied these three missions disagree over their purpose. But irrespective of Young's intentions, correspondence to and from the missionaries, held in LDS archives, reflects rising tension between Mormons and the non-Mormon world.
The first of the missionaries left Salt Lake City in May 1855. One band of men rode more than 350 miles north, into what is now Idaho—beyond Young's legal jurisdiction. Another headed 400 miles southwest—again, beyond Utah's boundaries—to the site of present-day Las Vegas, in the New Mexico Territory. A third pushed 200 miles southeast, to what is now Moab, Utah.
In August, Young wrote to the Las Vegas missionaries, working among Paiutes, to congratulate them on the "prosperity and the success which has thus far attended your efforts" and to exhort them to start baptizing the Indians and to "[g]ain their confidence, love and esteem and make them feel by your acts that we are their real friends." In all, the missions would report baptizing scores of Indians. (What the Indians made of the ritual was not recorded.)
In an October 1, 1855, letter to a friend, John Steele, an interpreter at the Las Vegas mission, suggested another motive. "If the Lord blesses us as he has done," he wrote, "we can have one thousand brave warriors on hand in a short time to help to quell any eruption that might take place in the principalities." (In 1857, the Utah militia, under Young's command, would number about 4,000.)
The following summer, Young counseled secrecy to another church leader, John Taylor, president of the New York City-based Eastern States Mission (and, eventually, Young's successor as president of the church). "[M]issionaries to the Indians and their success is a subject avoided in our discourses and not published in the 'News,'" he wrote on June 30, 1856, to Taylor, who was also editing The Mormon, a newspaper widely read by Eastern Mormons. "Wherever any thing comes to hand no matter from what source it would be well to carefully look it over and draw your pen through all such as you might deem it wisdom not to publish."