Thomas Donnelly is the director of Center for Defense Studies at the American Enterprise Institute.

The first part of his career was as a journalist, culminating in 1993 after six years as editor of Army Times; he has since also been editor of Armed Forces Journal. After a brief stint as executive editor of The National Interest, Donnelly then joined the staff of the House Armed Services Committee as director of the policy group.

In 1999, he moved to the Project for the New American Century and in 2002 to AEI.  He has also served professor of national security studies at the Maxwell School of Public Administration at Syracuse University, as a member of the U.S. China Economic and Security Review Commission, and as director of strategic initiatives for the Lockheed Martine Corporation.

Donnelly's recent work at AEI includes a study on the requirements for U.S. land force, co-authored with Frederick Kagan, Ground Truth, and a collection of essays, Lessons for a Long War.  He is the author or co-author of five further books, including The Military We Need: Defense Requirements of the Bush Doctrine; Operation Iraqi Freedom: A Strategic Assessment; Rebuilding America's Defenses: Strategy, Forces and Resources for a New Century; Operation Just Cause: The Storming of Panama, and Clash of Chariots: A History of Armored Warfare.

He holds a B.A. in Philosophy from Ithaca College and a master's degree in international relations from Johns Hopkins Scholl of Advanced International studies.  Donnelly  lives in Bethesda, Maryland.