Overview
From 1857 to 1858, the James Buchanan administration sought to quell a non-existent rebellion that they had been informed was taking place in Utah Territory by Mormon settlers. He sent U.S. forces there, in what was known as the Utah Expedition. The Mormons, fearful that the large U.S. military force had been sent to annihilate them, made preparations for defense. Though bloodshed was to be avoided, and the U.S. government also hoped that its purpose might be attained without the loss of life, preparations were made for war. Firearms were manufactured or repaired by the Mormons, scythes were turned into bayonets, and long-unused sabres were burnished and sharpened.
Rather than engaging the enemy directly, Mormon strategy was one of hindering and weakening them. Daniel H. Wells, lieutenant-general of the Nauvoo legion, instructed Major Joseph Taylor, "On ascertaining the locality or route of the troops, proceed at once to annoy them in every possible way. Use every exertion to stampede their animals and set fire to their trains. Burn the whole country before them and on their flanks. Keep them from sleeping, by night surprises; blockade the road by felling trees or destroying the river fords where you can. Watch for opportunities to set fire to the grass on their windward, so as, if possible, to envelop their trains. Leave no grass before them that can be burned. Keep your men concealed as much as possible, and guard against surprise." The Mormons blocked the army's entrance into the Salt Lake Valley, and weakened the U.S. Army by hindering them from receiving provisions.
However, while the confrontation between the Mormon militia, called the Nauvoo Legion and the U.S. Army involved some destruction of property and a few brief skirmishes in what is today southwestern Wyoming, no actual battles occurred between the contending military forces.
Despite this, the confrontation was not bloodless. At the height of the tensions, on September 11, 1857, more than 120 California-bound settlers from Arkansas, Missouri and other states, including unarmed men, women and children, were killed in remote southwestern Utah by a group of local Mormon militiamen. They first claimed that the migrants were killed by Native Americans. This event was later called the Mountain Meadows massacre and the motives behind the incident remain a mystery.
The "Aiken massacre" took place the following month. In October 1857, Mormons arrested six Californians traveling through Utah and charged them with being spies for the U.S. Army. They were released but later murdered and robbed of their stock and $25,000. Other incidents of violence have also been linked to the Utah War, including an Indian attack on the Mormon mission of Fort Limhi in eastern Oregon Territory. They killed two Mormons and wounded several others. The historian Brigham Madsen notes, "he responsibility for the lay mainly with the Bannock." David Bigler concludes that the raid was probably instigated by members of the Utah Expedition who were trying to replenish their stores of livestock which had been stolen by Mormon raiders.
Taking all incidents into account, MacKinnon estimates that approximately 150 people died as a direct result of the year-long Utah War, including the 120 migrants killed at Mountain Meadows. He points out that this was close to the number of people killed during the seven-year contemporaneous struggle in "Bleeding Kansas."
In the end, negotiations between the United States and the Latter-day Saints resulted in a full pardon for the Mormons, the transfer of Utah's governorship from church President Brigham Young to non-Mormon Alfred Cumming, and the peaceful entrance of the U.S. Army into Utah.
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