The Ballad of Lefty Brown
(2017)

Governor James Bierce (Jim Caviezel), a friend of Edward Johnson (Peter Fonda) who was to become a State Senator, ordered his murder. Johnson was going to vote against a railroad proposal and Bierce thought in doing so Johnson was stymieing progress.

Edward's widow Laura (Kathy Baker) hears the confession and demands justice be done "Eddie's way." Bierce is hanged by Lefty Brown (Bill Pullman) who had promised to bring Johnson's killers to justice. He then heads out of town to disappear, as killing a governor without a trial will make the U.S. Government attempt to hunt him down and hang him in turn for Bierce's death.

Thanks Spectre!