As we consider our incredible range of urgent international and defense affairs – challenges with our deepest Intelligence Gathering secrets revealed, China, Russia, North Korea, Syria, Iran – all while coordinating a military exit from Afghanistan, a question: How much does Presidential Leadership matter? Joe Nye is a former US Asst. Secretary of Defense and currently University Distinguished Service Professor at Harvard’s Kennedy School of Government. His new book is “Presidential Leadership and the Creation of the American Era.” Prof. Nye joined me for “Conversations with Thinkers.”