President-elect Donald Trump on Monday wouldn’t rule out military or economic action as part of his avowed desire to have the U.S. take back control of the Panama Canal and acquire Danish-controlled Greenland. Asked at a press conference whether he would avoid using military or economic coercion in Panama and Greenland, Trump said, "No, I can't assure you on either of those two. But I can say this, we need them for economic security." We talk to Philip Brenner, Professor Emeritus of International Relations and History at American University.