VINITA, Okla. -- J.D. Baldridge, 73, has official government documents showing him to be a descendant of a full-blood Cherokee. He has memories of a youth spent among Cherokee neighbors and kin, at tribal stomp dances and hog fries. He holds on to a fair amount of Cherokee vocabulary. " Salali," Baldridge says, his face creasing into a smile at the word. "Squirrel stew. Oh, that was good." What Baldridge, a retired Oklahoma county sheriff, also has is at least one black ancestor, a former slave of a Cherokee family. That could get Baldridge cast out of the tribe, along...