In an excerpt from his memoir, William Perry reflects on his diplomatic mission to Pyongyang intended to prevent North Korea from obtaining nuclear weapons and how the agreement eventually fell apart, creating the hostile negotiating atmosphere the U.S. faces today.

Former Secretary of Defense William Perry speaks on the recent statements made by President Trump about North Korea.

Former U.S. Secretary of Defense William Perry delivered a sobering talk and Q&A in Hanover Thursday, focusing on the potential for nuclear devastation in today's global environment. His lecture, part of the Osher Lifelong Learning Institute at Dartmouth's summer lecture series, was largely an attempt at a wake up call.