What really happened in the brushy South Texas wild that day? How one shot turned a genteel quail hunt into a political crisis? The delicate and the dangerous meet in the ranch lands of South Texas. In the winter, quail gather in the soft gold of prairie sedge, but snakes, scorpions and wild-boar-like javelina lurk too. In 1999 a fourth-generation South Texas rancher named Tobin Armstrong testified before Congress that he sometimes found illegal immigrants dead of dehydration in the unforgiving brush of his 49,300-acre ranch. It was there that Vice President Dick Cheney, out with a hunting party that...