The federal military expedition against the Mormons led by A.S. Johnston resulted in a peaceful settlement before it broke out into an all out war. But what if it did result in an actual war?
Wikipedia article here: https://en.wikipedia.org/wiki/Utah_War
This one is also worth looking at as an indication of what could have happened: https://en.wikipedia.org/wiki/War_of_Canudos
Wikipedia article here: https://en.wikipedia.org/wiki/Utah_War
This one is also worth looking at as an indication of what could have happened: https://en.wikipedia.org/wiki/War_of_Canudos