From the 1930s to the 1960s, the United States knowingly used and discarded an entire tribe of people. The Navajo worked unprotected in the uranium mines that fueled the Manhattan Project and the Cold War. Long after these mines were abandoned, Navajos in all four corners of the Reservation (which borders Utah, New Mexico, and Arizona) continued grazing their animals on sagebrush flats riddled with uranium that had been blasted from the ground. They...