U.S. officials are concerned nuclear weapons or materials could fall into the hands of terrorists. We?ll talk about how likely that really is. Laura talks with Leonard Spector, Deputy Director at Monterey Institute of International Studies Center for Non-proliferation Studies www.miis.edu and Jim Walsh, International Security Program; Science, Technology, and Public Policy Program at Harvard University Kennedy School of Government http://ksgnotes1.harvard.edu/bcsia/bcsia.nsf/www/home