Why were Mormons run out of Missouri?

Its quite complicated. Basically, in some areas, the Mormons were becoming quite dominant and began to affect the local political races, making the locals quite upset. The locals began to fight the Mormons, trying to kick them out of the area. The violence spread and the state government got involved. The state government decided the best solution was to tell the Mormons to leave the state. The governor issued an extermination order, requiring the Mormons to leave immediately.