Loosely based on the real "Battle of Athens" in Athens, Tennessee. In 1946 a political party made up of mostly returning GIs from WWII took on a corrupt political machine that ran the county and most of the state. When ballot boxes were stolen and taken to the jail by deputies, gunfire and explosives were used to retrieve them. There were no fatalities, but several injuries on both sides of the conflict.
If you are interested in the event this movie is based on, check out the book "The Fighting Bunch" by Chris DeRose.