This film is very simple, yet incredibly profound in the way the story is told. The throughline is that Jack is a man out of time. He is cowboy who has yet to come into agreement with the new world of automobiles, airplanes, the pace of society and the way it moves far too fast, and even the new way of thinking that doesn't belong to the old west, where every decision was made based on providing freedom and breaking free from any sort of fences placed around a man--literal or metaphorical.
We see Jack's loyalty to Paul cause him to break into prison to break his friend out, but Paul has changed. He is different than Jack, he's come into agreement with the new man he is and this man lives in a new world. That is why he stays behind. And, it is Jack's loyalty that causes him to be chased down by the law.
In the end, it isn't the law that captures Jack. In fact, Jack is able to outmaneuver the police and their new technology (the helicopter) with only the land and a rifle. No, it isn't the law that gets him: it is this newer, faster paced life that everyone has fallen victim to. A way of living that his horse is frightened so terribly by that it only freezes while standing in the midst of speeding cars that won't even stop to help them. They just whiz by because they have some place to be. This inability to slow down is what ultimately cuts Jack down.
