Mark Esper, U.S. Secretary of Defense, joins Christiane Amanpour in Saudi Arabia to defend the U.S. government's decision to withdraw troops from Northern Syria, paving the way for Turkey's invasion of the Kurdish held region. Our Michel Martin sits down with Tom Mueller, author of "Crisis of Conscience", to unpack why whistleblowing is ultimately about American values. Walter Isaacson speaks to Richard Stengel, former Under Secretary of State under Obama and author of "Information Wars", to discuss his experience of fake news during Russia's invasion of Crimea.To learn more about how CNN protects listener privacy, visit cnn.com/privacy