Casey Martin is playing in a U.S. Open again. In a cart. With a lower right leg that's a cause for constant pain and nearly as much attention. The first time, in 1998 at Olympic, he was a fledgling touring pro, a Stanford graduate, a friend of Tiger Woods. This time, he's a 40-year-old golf coach at the University of Oregon just hoping to make the cut. Fourteen years have changed everything and nothing....