Bureau of International Security and Nonproliferation

The Bureau of International Security and Nonproliferation (ISN) is a bureau within the United States Department of State responsible for managing a broad range of nonproliferation and counterproliferation functions. The bureau leads U.S. efforts to prevent the spread of weapons of mass destruction (nuclear, chemical, and biological weapons) and their delivery systems.

Mission

Preventing the spread of WMD, delivery systems, and advanced conventional weapons capabilities — and rolling back such proliferation where it has already taken root — is the mission of the Bureau of International Security and Nonproliferation (ISN). In close collaboration with other bureaus within the State Department, other U.S. agencies, and a diverse range of international and non-governmental partners, ISN tracks, develops, and implements effective responses to proliferation threats and shapes the international security environment to prevent their recurrence.