A lot of people don't know this, but Keven Costner has actually been in three post-apocalyptic science fiction movies. The first is Waterworld, the second was the Postman, and the third was 3,000 Miles To Graceland. 3,000 Miles is much more subtle than the other two, but the clues are there. First of all, it co-stars Kurt Russell (star of post-apocalyptic movies Escape from NY, Escape from LA,and Soldier, ) and also features Ice-T (from post-apocalyptic movies Tank Girl, Johnny Mnemonic, and Leprechaun in the Hood). Secondly, it starts off with an animated sequence where two bio-mechanical scorpions are fighting each other in the desert. From there it gets pretty obvious. After the world has been destroyed by a plague of genetically engineered scorpions (designed by a US military that got out of control) the surviving population has turned away from Christianity to the cult of Elvis (there is also a smaller religion devoted to Frank Sinatra). The movie describes the struggle of a small group of heroes and villains who are trying to find and reach Graceland (AKA Mecca) where the world is rumored to still be pure. On their journey they learn the truth about their world, the truth about their religion, and the truth about themselves.

Frankly, i don't know why this isn't understood by most people. It's the only way the movie makes any sense.