What historical events led to hostilities between the U.S. and the Mormons?

Answer 1

The short-lived war between the US and the Mormons occurred when the US government sent a non-Mormon, unelected appointee to the territory inhabited by the Mormons and announced without discussion that this individual would be the governor. The Mormons refused to accept the imposition of an unelected and unsympathetic government. The US sent the Army to impose the government's will. The Mormons prepared to fight back, and Army arrived, negotiations resolved the conflict, and no hostilities actually took place.