Many of us think of the history of the United States' interaction with the world as one of relentless expansion, growth and engagement. From the early colonies, through the Spanish American War, through involvement in two world wars and of course, the Cold War era, the story is one of America increasingly getting involved with countries in its region and around the globe. Charles Kupchan has a thing or two to say about that. He recently researched and wrote the book, "Isolationism: A History of America's Efforts to Shield Itself from the World." He joined David Priess to talk through the idea that much of American history in terms of its relations to the outside world can be explained by isolationist tendencies, with only occasional bursts into more engagement, most notably in the Cold War world. But is that period coming to an end? And how does Donald Trump play into these trends?