The Mountain Meadows Massacre was caused in part by events relating to the Utah War (May 1857 – July 1858), an armed confrontation in Utah Territory between the United States Army and Mormon pioneers. In the summer of 1857, however, Mormons experienced a wave of war hysteria, expecting an all-out invasion of apocalyptic significance. From July to September 1857, Mormon leaders prepared Mormons for a seven-year siege predicted by Brigham Young. Mormons were to stockpile grain, and were prevented from selling grain to emigrants for use as cattle feed. As far-off Mormon colonies retreated, Parowan and Cedar City became isolated and vulnerable outposts. Brigham Young sought to enlist the help of Indian tribes in fighting the "Americans", encouraging them to steal cattle from emigrant trains, and to join Mormons in fighting the approaching army.

In August 1857, Mormon apostle George A. Smith, of Parowan, set out on a tour of southern Utah, instructing Mormons to stockpile grain. Scholars have asserted that Smith's tour, speeches, and personal actions contributed to the fear and tension in these communities, and influenced the decision to attack and destroy the Baker–Fancher emigrant train near Mountain Meadows, Utah. He met with many of the eventual participants in the massacre, including William H. Dame, Isaac Haight, and John D. Lee. He noted that the militia was organized and ready to fight, and that some of them were anxious to "fight and take vengeance for the cruelties that had been inflicted upon us in the States". On his return trip to Salt Lake City, Smith camped near the Baker–Fancher party. Jacob Hamblin suggested the Fanchers stop and rest their cattle at Mountain Meadows. Some of Smith's party started rumors that the Fanchers had poisoned a well and a dead ox, in order to kill Indians, rumors that preceded the Fanchers to Cedar City.. Most witnesses said that the Fanchers were in general a peaceful party that behaved well along the trail.

Among Smith's party were a number of Paiute Indian chiefs from the Mountain Meadows area. When Smith returned to Salt Lake, Brigham Young met with these leaders on September 1, 1857, and encouraged them to fight against the "Americans". The Indian chiefs were reportedly reluctant. Some scholars theorize, however, that the leaders returned to Mountain Meadows and participated in the massacre. However, it is uncertain whether they would have had time to do so.

Background

In early 1857, several groups of emigrants from the northwestern Arkansas region started their trek to California, joining up on the way and known as the Baker–Fancher party. This group was relatively wealthy, and planned to restock its supplies in Salt Lake City, as most wagon trains did at the time. The party reached Salt Lake City with about 120 members. In Salt Lake, there was an unsubstantiated rumor that the widow of the revered Mormon martyr Parley P. Pratt recognized one of the party as being present at her husband's murder. (citing "Argus", an anonymous contributor to the Corinne Daily Reporter whom Stenhouse met and vouched for).

For the decade prior to the Fanchers' arrival there, Utah Territory existed as a theocracy led by Brigham Young. As part of Young's vision of a pre-millennial "Kingdom of God", Young established colonies along the California and Old Spanish Trails, where Mormon officials governed by "lay[ing] the ax at the root of the tree of sin and iniquity".In 1856, Young said "the government of God, as administered here" may to some seem "despotic" because "[i]t lays the ax at the root of the tree of sin and iniquity; judgment is dealt out against the transgression of the law of God"; however, "does not [it] give every person his rights?" . Two of the southernmost establishments were Parowan and Cedar City, led respectively by Stake Presidents William H. Dame and Isaac C. Haight. Haight and Dame were, in addition, the senior regional military leaders of the Mormon militia. During the period just before the massacre, known as the Mormon Reformation, Mormon teachings were dramatic and strident. The religion had undergone a period of intense persecution in the American midwest, and faithful Mormons made solemn oaths to pray for vengeance upon those who killed the "prophets" including founder Joseph Smith and most recently apostle Parley P. Pratt, who was murdered in April 1857 in Arkansas.

Utah War

In July 1857, while the Baker–Fancher party was en route to Utah Territory, Mormons began hearing rumorsChurch leaders mentioned such rumors in sermons as early as July 2 (Heber C. Kimball: JD 5:86) and July 5, 1857 (referring to rumors of the approaching troops and warning them to stay away). that the United States had launched an expedition to invade the territory and depose its theocratic government. For almost a decade, relations between Utah and the federal government had deteriorated over the issue of polygamy and the role of Mormon institutions versus that of federal ones in the territory.In 1856, the newly formed Republican Party had campaigned against Mormon practices of polygamy as "relics of barbarism", and Democrat James Buchanan, assuming office in March 1857, was under political pressure to subdue the perceived Mormon rebellion. By July 1857, Young's replacement, Alfred Cumming, was appointed, and a fourth of the entire U.S. army, some 2,500 dragoons, were already on the march.

As news of the approaching army spread, the coming invasion took on apocalyptic significance. Mormons saw it as a threat to their existence.George A. Smith, August 2, 1857, JD 5:101; (at the time of the massacre, the Mormon leadership believed reports that the troops had the "ostensible design for destroying the Latter-day Saints"). Members of the First Presidency framed the confrontation as a battle between the Kingdom of God and minions of the Devil. (teaching on July 26, 1857 that "God has commenced to set up his kingdom on the earth, and all hell and its devils are moving against it."); Heber C. Kimball, August 2, 1857, JD 5:129 ("The world is going to seek to destroy us from the earth. (Voice: 'They will destroy themselves.') They will destroy themselves, as the Lord liveth, and the day of their destruction has come. (Voices: 'Amen'.)"). Some Mormons in southern Utah taught that the invasion was the beginning of the Millennium,. and the prevailing understanding there was that the U.S. Army intended to wipe out the Mormons as a people.; . In preparation for a seven-year siege predicted by Brigham Young, Mormon leaders began accelerating an existing program for stockpiling grain. (counseling Native Americans to stockpile all the berries and wheat they could glean in preparation for the seven-year siege predicted by Brigham Young); Heber C. Kimball, August 23, 1857, JD 5:171; Heber C. Kimball, September 6, 1857, JD 5:213 (predicting that imminently, "the people of the nations will come by hundreds and by thousands for food, and for raiment, and for protection" in the Utah Territory). Mormons were told to sell their clothing to buy as much grain as possible,Heber C. Kimball, September 6, 1857, JD 5:213. and not to use grain as animal feed nor sell it to emigrants for this purpose.; .

Defiant against the United States, Brigham Young warned "mobocrats", particularly past Mormon persecutors and the "priests, editors, and politicians who have howled so long about us", to stay away from the territory, or "we will attend to their cases".. He stated that if such persons entered the territory, "they will find a 'Vigilance Committee and they will "find the Danites". But Young denounced plans by Mormons to rob "innocent" emigrant trains, saying that such robbers themselves would "be overtaken by a 'Vigilance Committee. He wanted to ensure that "the good and honest may be able to pass from the Eastern States to California...in peace".

Young ordered pioneer settlements furthest afield to pull up stakes–evacuating colonies in San Bernardino (southern California), Las Vegas (southern Nevada), Carson Valley (western Nevada), and Fort Bridger (western Wyoming).. Thereafter, the farthest remaining outpost of Mormonism were the outlying Mormon colonies at Cedar City (led by Stake President-Major Isaac C. Haight) and Parowan (led by Stake President-Colonel William H. Dame), two infant fortress-villages near Mountain Meadows where the massacre took place. These settlements were nearly 300 miles from the Salt Lake City headquarters, and only reachable by a three days' journey on horseback, the messengers changing mounts at various settlements along the way.. Mormons in and around the Cedar City area were to be the first defense against an attack from the south which the Mormons feared and which the US Army was preparing for.. The word from Mormon headquarters was that the approaching U.S. Army had orders to murder every believing Mormon,George A. Smith, August 2, 1857, JD 5:101; (at the time of the massacre, the Mormon leadership believed reports that the troops had the "ostensible design for destroying the Latter-day Saints"); (saying this was the understanding among southern Utah Mormons). and that the troops were coming directly from Missouri,

On August 5, 1857, Brigham Young declared martial law. All borders were to be sealed to further travel through Utah by emigrants. As a Mormon woman evacuating Carson Valley explained, "The last trains of this year would not get through, for they were to be cut off." Young also made it illegal to travel through Utah without a permit,; ; . but no safe conduct pass was made available to the Baker–Fancher train by Territorial or local officials. The party would not have been aware of Young's decree as it was only made public on September 15, 1857..

Emigrant trains arriving from the east presented an opportunity for Mormons to trade or sell foodstuffs and other supplies, and until the Utah War, most were friendly and willing to help travelers pass through the Utah Territory.. The Baker–Fancher train encountered residents along the way who were obeying Young's recent order to stockpile supplies in expectations of all-out war with approaching U.S. troops.. The Mormons were directed not to sell any food to the enemy, as the emigrant train was labeled.; .

George A. Smith's circuit through southern Utah