Nathan Freier is a senior associate in the International Security Program at CSIS. He joined CSIS in April 2008 after completing a 20-year career in the U.S. Army. From August 2008 to July 2012, Mr. Freier also served as a visiting research professor at the U.S. Army War College's Peacekeeping and Stability Operations Institute under the provisions of the Inter-Governmental Personnel Act. His last military assignment was as director of national security affairs at the Army War College’s Strategic Studies Institute (SSI). Freier is a veteran of numerous strategy development and strategic planning efforts at Headquarters, Department of the Army (DA); the Office of the Secretary of Defense (OSD); and two senior-level military staffs in Iraq. Prior to joining SSI, he served in the Office of the Deputy Assistant Secretary of Defense for Strategy. His principal responsibilities included development of the 2005 National Defense Strategy. Prior to that, he was a U.S. Army fellow/visiting scholar at the University of Maryland’s Center for International and Security Studies (CISSM) and a strategist with DA's Strategic Plans, Concepts, and Doctrine Directorate. At CISSM, he examined strategic risk and terrorism. At DA, his duties included army preparation for, participation in, and response to the 2001 Quadrennial Defense Review and army and joint strategic planning for the war on terrorism. Freier twice deployed to Iraq. From January to July 2005, he served in the Strategy, Plans, and Assessments Directorate of Headquarters, Multi-National Force–Iraq, and from May to August 2007, he served as a special assistant to the commander, Multi-National Corps–Iraq. Prior to his service as an army strategist, Freier held various leadership and staff positions as a field artillery officer in the United States, Europe, and the first Persian Gulf War. He continues to provide expert advice to the national security and defense communities on a range of issues. Among his research interests and areas of expertise are defense and military strategy and policy development; strategic net and risk assessment; unconventional and hybrid threats and conflicts; and anti-access/area denial challenges. He holds masters’ degrees in both international relations and politics and is a graduate of the U.S. Army’s Command and General Staff College.