During the Cold War, the purpose of the United States nuclear arsenal was to deter nuclear threats to the United States, primarily from the Soviet Union. Today, in the post-9/11 world, the most urgent nuclear weapon threats to the United States are not from another major power’s deliberate use of them, but instead are from non-state terrorist actors or from the regional proliferation of such
weapons into unreliable hands.
U.S. nuclear policy and strategy in this post-Cold War and post-9/11 security environment
have not been well articulated and as a consequence are poorly understood both within and
outside American borders. This situation has led to doubts and uncertainties about the roles and
missions of nuclear weapons and their value against 21st century security threats, including allies’
uncertainties about U.S. assurances as they relate to emerging nuclear-armed neighboring states.