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), their delivery systems, advanced conventional weapons, and related materials, technologies, and expertise.

It was created on September 13, 2005 when the Bureau of Arms Control and the Bureau of Nonproliferation were merged. Stephen G. Rademaker was the first the Acting Assistant Secretary of State for International Security and Nonproliferation. He had been the Assistant Secretary for the Bureau of Arms Control, and in February 2005 he was named the head of the Bureau for Nonproliferation pending the two bureaus' merger.

The Bureau's role within the Department of State is to spearhead efforts to promote international consensus on WMD proliferation through bilateral and multilateral diplomacy, and to address WMD proliferation threats posed by non-state actors and terrorist groups by improving physical security, using interdiction and sanctions, and actively participating in the Proliferation Security Initiative.

The bureau also coordinates the implementation of international treaties and arrangements. It seeks to work with international organizations such as the United Nations, the G7, NATO, and the International Atomic Energy Agency to reduce and eliminate threats posed by weapons of mass destruction, and to support foreign partners in their efforts.