North Korea ups the nuclear ante, threatening a nuclear chain reaction in the region. We talk about the implications of the country's first test.
Mike Shuster, NPR diplomatic correspondent
Kurt M. Campbell, senior vice president at the Center for Strategic and International Studies and former deputy assistant secretary of defense
Stephen Peter Rosen, professor of national security and military affairs, director of the John M. Olin Institute for Strategic Studies at Harvard University. His article, "After Proliferation: What to Do If More States Go Nuclear," appeared in the September/October issue of Foreign Affairs magazine.