On Tuesday, President Trump gave his first address to the United Nations General Assembly, boasting about the size of the U.S. military and threatening to "totally destroy" North Korea. "[N]uclear war is a real threat," says Jeffrey Sachs, leading economist and director of the Center for Sustainable Development at Columbia University. "It’s not some idle imagination right now. You have two leaders—both seem unstable—yelling at each other. Both have nuclear arms."
(Watch from the 27 minute 50 second mark, till the end of the segment.)