The debate about appropriate purposes and policies for U.S. nuclear weapons has been under way since the beginning of the nuclear age. With the end of the Cold War, the debate has entered a new phase, propelled by the post-Cold War transformations of the international political landscape. This volume--based on an exhaustive reexamination of issues addressed in "The Future of the U.S.-Soviet Nuclear Relationship" (NRC, 1991)--describes the state to which U.S. and Russian nuclear forces and policies have evolved since the Cold War ended. The book evaluates a regime of progressive constraints for future U.S. nuclear weapons policy that includes further reductions in nuclear forces, changes in nuclear operations to preserve deterrence but enhance operational safety, and measures to help prevent proliferation of nuclear weapons. In addition, it examines the conditions and means by which comprehensive nuclear disarmament could become feasible and desirable.