The Postman (1997) on Netflix

In the year 2013 civilization has all but destroyed itself. After a war that decimated the government and most of the population of the United States (possibly the world) people struggle to survive against starvation and rogue groups of armed men. One such group is called the Holnists. This group is bigger than any other and their leader, General Bethlehem, has delusions of ruling the country. A drifter is captured by the group and forced to join. He escapes at the first chance and happens on a mail jeep with a skeleton in it. The skeleton is wearing a postal uniform and the drifter takes it to keep him warm. He also finds a mailbag and starts conning people with old letters. The hope he sees in the people he delivers to changes his plans and he decides that he must help bring the Holnists down.