James Martin Center for Nonproliferation Studies

The James Martin Center for Nonproliferation Studies (CNS), established in 1989, also known as the Center for Nonproliferation Studies, is a research and training center dedicated to addressing the global challenges posed by nuclear weapons and other weapons of mass destruction. It is the largest largest nongovernmental organization in the United States focused exclusively on nonproliferation issues. Its mission is to educate and train future generations of specialists in nonproliferation, and to provide timely analysis and information to support policy and research efforts. After a large endowment gift in 2007 by James Martin, CNS was renamed in his honor.

The headquarters of CNS is at the Middlebury Institute of International Studies at Monterey, in Monterey, California. In addition, CNS oversees the Vienna Center for Disarmament and Non-Proliferation in Vienna, Austria, and also maintains a significant presence at its offices in Washington, D.C., to facilitate engagement with policymakers, international organizations, and other stakeholders. CNS also publishes the Nonproliferation Review and NonPro Notes. In August 1998, CNS established the Newly Independent States Representative Office (NISRO) offices in Almaty, Kazakhstan, which was closed in 2009.

On August 26th, 2025, CNS announced that it would open new offices on the main Middlebury College campus in Vermont. The next day, on August 27th, the President of Middlebury College announced the closure of MIIS and that all academic programs at the institute would conclude sometime in July 2027. CNS, however, as a "self-sustaining center", will remain open in Monterey, and under the umbrella of Middlebury College after 2027.