Tommy Lee Jones, as actor and director, clearly cares a lot about the Western. Is there an audience that cares with him? The once-dominant genre has declined so steeply since the 1970s that each new one is an event, and Jones has become one of the few people still riding herd on the form. (Though ailing at the movies, the myth of the West is alive and well in American politics, currently full of gun-totin’, hog-castratin’ candidates.) The Homesman is so good it makes you wish Jones could somehow make a Western a year, just to keep exploring the pockets of American frontier experience that still need filling in. This one offers a series of new wrinkles, beginning with its route: The story goes from west to east, the opposite of most Westerns.