Christopher Dark

Four astronauts returning from mankind's first mission to Mars enter a time warp and crash on a 26th Century Earth devastated by atomic war. (imdb)

As a man returns home to see his dying father, the story of the alienation between father and son is told in flashback. Purposely letting his daughter's lover get lynched, shooting the lynched man's father when he threatens him with a gun, and the bullying tactics used by him as a Sheriff causes the son to leave. The son now plans to ruin his father and get his Sheriff's badge removed. (imdb)

It's known that the President will be passing through a certain small town... and it's known that someone will attempt to kill him there. (imdb)