He hid behind the skirts of two Superpowers."A more vital piece of U.S. history would be hard to find, " gushed the Boston Globe last week about a new item in the Kennedy Library and Museum, a map of Cuba. The Library obtained it from the estate of Robert L. White, a collector who had earlier received it from JFK's late secretary, Evelyn Lincoln. "This map bears the marks of history, " continues the Globe story, "a series of X marks in black ink, crosshatched east and west of Havana by President John F. Kennedy, and two foreboding words scrawled...