Robert McNamara is worried. He knows how close we've come. His counsel helped the Kennedy administration avert nuclear catastrophe during the Cuban Missile Crisis. Today, he believes the United States must no longer rely on nuclear weapons as a foreign-policy tool. To do so is immoral, illegal, and dreadfully dangerous.

This article, the cover story for the May/June 2005 issue of Foreign Policy, began as a talk McNamara delivered at Stanford to CISAC researchers, staff, and friends on Oct. 18, 2004.