Dark Command (1940)

When transplanted Texan Bob Seton arrives in Lawrence, Kansas, he finds much to like about the place--especially Mary McCloud, daughter of the local banker, but politics is in the air: it's just prior to the Civil War and there is already a sharp division in the Territory as to whether it will remain slavery-free. When he gets the opportunity to run for marshal, Seton finds himself running against respected local schoolteacher William Cantrell. Not all is what it seems, though: While acting as the upstanding citizen in public, Cantrell is dangerously ambitious and prepared to do anything to make his mark, and his fortune, on the Territory. When he loses the race for marshal, he forms a group of raiders who run guns into the territory and rob and terrorize settlers throughout the territory. Eventually donning Confederate uniforms, it is left to Seton and the good citizens of Lawrence to face Cantrell and his raiders in one final clash.