Come On, Rangers

The governor decides that Texas (having achieved statehood) no longer needs the Texas Rangers, believing that the US Cavalry can maintain order. Roy Rogers had been an officer in the Rangers but now applies to join the Cavalry. An unscrupulous ex-Senator forms a private "State Patrol" that runs a protection racket, charging ranchers for protection while robbing and killing those that don't pay (including Roy's brother). Roy deserts the Cavalry to find the bad guys who killed his brother.

Odds and ends: when the State Patrol dons its outlaw gang persona, it rides white horses and is known as the White Horse Raiders.

Familiar faces: The leader of the US Cavalry is played by J. Farrell MacDonald, of "you must be thinking of two other trees" fame from It's a Wonderful Life.