The United States recently threatened military action against Syria in response to the Syrian government’s alleged use of chemical weapons. Similar threats have been made against states suspected of trying to develop nuclear arsenals such as North Korea and Iran. Yet the U.S., the U.K., France, Russia, and China have thousands of active nuclear weapons of their own. Is there a morally significant difference between nuclear or chemical weapons and conventional weapons? Should we work toward total disarmament, or do we need these weapons as a deterrent to rogue states?