Mike Mullen, retired admiral and former Chairman of the Joint Chiefs of Staff, says the national security challenges the new Trump administration will face are plentiful. Mullen gives insight into President-elect Donald Trump’s pick for national security advisor, General Mike Flynn. What kind of leader will he be? And how will he guide Trump – who has no national security experience – on issues centered around Russia, China, and Syria? Foreign policy experts, journalists, students and Aspen Institute President and CEO Walter Isaacson pose questions to Mullen, a featured speaker at the Aspen Institute’s Washington Ideas Roundtable series.