LIKE MANY other southern Arizonans, I am deeply grateful to the few dozen vigilantes calling themselves Minutemen who set up camp along the Arizona-Mexico border last month. That few people around here were much impressed with a bunch of retirees in camouflage playing soldier, and that there turned out to be almost as many reporters as patriots on the ground, was irrelevant: We were just thrilled by the publicity. We’ve been trying to get the rest of the country to notice what’s going on down here for years. U.S. immigration policy has turned the Arizona desert between Tucson and the...