Vann H. Van Diepen has been Principal Deputy Assistant Secretary of State for International Security and Nonproliferation (ISN) since June 2009. From February 2006 to June 2009, he was National Intelligence Officer for Weapons of Mass Destruction and Proliferation in the Office of the Director of National Intelligence, advising the Director on those issues, serving as the Intelligence Community (IC) spokesman on them and producing National Intelligence Estimates and other IC analyses.
From September 2005 to February 2006, Mr. Van Diepen directed the State Department’s Office of Missile Threat Reduction. He oversaw policy for the nonproliferation of missiles capable of delivering WMD, including export controls, regimes, sanctions, and interdiction. He also headed the U.S. Delegations to the Missile Technology Control Regime (MTCR) and the Hague Code of Conduct Against Ballistic Missile Proliferation (HCOC).
From July 1991 to September 2005, he directed the Office of Chemical, Biological and Missile Nonproliferation. In addition to the above missile responsibilities, he also oversaw policy for the nonproliferation of chemical/biological weapons (CBW), and headed the U.S. Delegation to the Australia Group CBW nonproliferation regime. Until April 1999, he also oversaw State Department participation in the Biological Weapons Convention (BWC) and Chemical Weapons Convention (CWC).
From December 1989 to July 1991 he analyzed East-West arms control issues in State’s Political-Military Bureau. He served in State’s Bureau of Intelligence and Research analyzing Soviet and other non-U.S. strategic forces from November 1982 to December 1989. He received a B.A. in International Studies from The American University in 1981, and an S.M. (scientiae magister) from MIT's Defense and Arms Controls Studies program in 1983.