2001 May 1 President Bush in a speech at the National Defense University stops just short of saying the U.S. will withdraw from the 1972 Antiballistic Missile Treaty (ABM). Bush made it clear that he intends to build a network of installations that will unquestionably violate a treaty that arms-control advocates argue has been the cornerstone of nuclear deterrence since Richard M. Nixon and Leonid I. Brezhnev signed it. That pact bans the very systems Mr. Bush alluded to today. "Nuclear weapons will still have a vital role to play in our security and that of our allies," Bush said. "We can and will change the size, composition, the character of our nuclear forces in a way that reflects the reality that the cold war is over."