In The Day Mars Invaded Earth (1963) Sci-Fi classic movie, the Martians are not the invaders, they're the ones protecting themselves from us after a US space probe lands on their planet.
Quirt Evans, an all round bad guy, is nursed back to health and sought after by a Quaker girl and finds himself having to choose between his world and hers.
Wealthy rancher G.W. McLintock uses his power to maintain peace between farmers, ranchers, land-grabbers, Indians, and corrupt officials in the territory.