Since the earliest days of the Cold War, the U.S. government has continuously revised a plan that would ensure continuity in the event of a nuclear attack. Garret M. Graff joins us to talk about the inner-workings of the plan – and how it’s evolved in the last six decades – which he writes about in “Raven Rock: The Story of the U.S. Government’s Secret Plan to Save Itself — While the Rest of Us Die” (Simon & Schuster). He speaks tonight to the World Affairs Council of Dallas-Fort Worth.