Woody Island is a speck of land in the middle of the South China Sea, not quite a square mile in size. Over the past 80 years it has been occupied by French Indochina, Imperial Japan, the Republic of China, the People’s Republic of China, South Vietnam, and, after a brief war in 1974, the People’s Republic again. Now known as Yongxing to the Chinese (or Phu Lam to the Vietnamese, who still lay claim to it), the island has an airstrip, a harbor, and a few hundred Chinese residents, none native-born, many of whom make their living as fishermen....