Under the Banner of Heaven by Jon Krakauer, 2003, Excerpts
In 1858, a year after the massacre, Brigham Young reluctantly agreed to admit federal troops into Utah and to step down as territorial governor, bringing an end to the threat of all-out war between the Saints and the United States. But persistent rumors that Mormons had committed unspeakable atrocities against the Fancher wagon kept drifting up from the southern settlements, threatening the fragile peace.
In 1862 Lincoln signed into law the Morrill Anti-Bigamy Act, which had been drafted specifically to “punish and prevent the practice of polygamy in the territories of the United States and to disapprove and annul certain acts of the territorial legislature of Utah.”
United States Army troops walking through downtown Salt Lake City.