I recently attended a presentation on the Utah War by historian David Bigler. For background on the Utah War of 1857-58, see my earlier post; this post will give a few of the interesting details in Bigler's presentation that adds to the basic story. He called it the United States' "First Civil War" (although it was the Mormons' third war). My notes are a little sketchy; for more complete coverage, see his book Forgotten Kingdom: The Mormon Theocracy in the American West, 1847-1896, a history of 19th-century Utah that (I'm told) doesn't pull any punches.
First, Bigler noted that land policy and surveying played a significant role in difficulties between Mormon settlers and the US government. When Mormons moved into the valley, various tracts of land were granted to settlers as individuals or families, and some of the resources were used communally. But when Utah was formally organized as a US Territory in 1850 (with Brigham Young as Territorial Governor), the US Land Office sent out government surveyors to survey the land as a prelude to public sale. You can see how this would become a flashpoint — the government did not recognize whatever title the Mormon settlers had to the land from LDS officials, and there was no guarantee the Mormon settlers already on the land would be able to purchase their tracts in a public sale. Predictably, the government surveyors met hostility in 1854-55 when they tried to lay property markers. [Even today, feds aren't particularly welcome out West.] Essentially, the Mormons were engaging in what is called "nullification" of federal land law. This became an issue in 1857 in the reports directed to President Buchanan that Utah was in a state of rebellion.
Federal judges weren't any more welcome than the surveyors. They were in competition with Utah's own probate courts (local courts authorized by the Territorial Legislature, but basically run by local LDS bishops) and it was apparently an exasperating experience for the federal judges. By 1856, all eight US district court judges had left Utah in frustration. This, too, found its way into the reports sent to President Buchanan.
The second big issue was the Mormon opinion of and relations with Native Americans. In simple terms, the Mormons viewed the Indians as descended from Israel (to American ears, a noble heritage), with Book of Mormon passages implying the Indians had a potentially promising future. That fact that some of those passages implied Indian resurgence would come at the expense of the Gentiles (i.e., the Euro-Americans who spent most of the 19th century displacing Native Americans) did not sit well with most Americans and it was 180 degrees out of synch with those who lived on the frontier.
But the political conflict came with the federal government's Office of Indian Affairs and those appointed as agents to the various tribes. They were jealous to protect their power (a formal monopoly on dealing with the Indians) and resented the contact between Mormons and Indians. Lest you think the Mormons were interfering with Uncle Sam's good works, consider what a rotten deal Indians got at every turn. Some agents were unscrupulous and corrupt, and used their position to make every dollar they could at the expense of their supposed wards, the Indian tribes. But even the sober and honest among them did little good for the Indians. It's no wonder the Indians had more sympathy for the Mormons than for the US government, but that result certainly didn't help the government's view of the Mormons.
So what I took away from the presentation was that difficulties with federal land policy and the Mormon view of the Indians were two issues that played a central role in creating the perception in Washington DC that Utah was in a state of rebellion. This led directly to the President appointing a new governor and sending a few thousand federal troops to accompany him to Utah. There were other topics Bigler touched on briefly: the religious fervor whipped up by LDS Reformation of 1856-57; Brigham Young's declaration of martial law in late 1857 and closure of the overland trails (which cut the country in half); militias that were formed in Nevada to march east against Utah; and the ultimate resolution of the crisis without serious fighting or significant bloodshed. Plenty more to talk about in a later post!