During the 2004 U.S. presidential campaign both President George Bush and his opponent, Senator John Kerry, said nuclear proliferation is the single greatest global threat. The five permanent members of the United Nations Security Council — the United States, Russia, China, Britain and France — all possess nuclear weapons. India, Pakistan and Israel have them as well. Iran and North Korea have been making headlines recently with their efforts to produce them. If a terrorist group were to acquire nuclear weapons and attack the United States, how would the U.S. know where — or against whom — to retaliate? It is one of many vexing questions sure to be debated at the 2005 non-proliferation treaty review — and for years to come. Full Story