Elbridge Colby

Co-Founder and Principal, The Marathon Initiative


Elbridge Colby is co-founder and principal of The Marathon Initiative, a new policy initiative focused on developing strategies to prepare the United States for an era of sustained great power competition.

Previously, Colby was from 2018-2019 the Director of the Defense Program at the Center for a New American Security, where he led CNAS’ work on defense issues.

Before that, he served as the Deputy Assistant Secretary of Defense for Strategy and Force Development from 2017-2018. In that role, he served as the lead official in the development and rollout of the Department’s preeminent strategic planning guidance, the 2018 National Defense Strategy (NDS). The NDS focuses the Department on the challenges to U.S. military superiority posed by China and Russia and therefore prioritizes sustaining the Joint Force’s warfighting edge against these major power competitors. Colby also served as lead official in the development of a number of key documents implementing this strategic shift, including the 2017 Secretary’s Force Planning Priorities and the 2018 Defense Planning Guidance. He also served as the primary DOD representative in the development of the 2017 National Security Strategy.

Prior to entering government service, Colby was from 2014 to 2017 the Robert M. Gates Senior Fellow at the Center for a New American Security. From 2010 to 2013 he was principal analyst and division lead for global strategic affairs at CNA. Earlier in his career he served for over five years in the U.S. Government at the Department of Defense, Department of State, and in the Intelligence Community working on a range of strategic forces, arms control, WMD, and intelligence reform matters, including service with the Coalition Provisional Authority in Iraq in 2003. Colby has also served on the staff of a number of government commissions, including the 2014 National Defense Panel, the 2008-2009 Strategic Posture Commission, and the 2004-2005 President’s WMD Commission.

Colby’s work has appeared in outlets such as Foreign Affairs, The Washington Post, The Wall Street Journal, The New York Times, Foreign Policy, The National Interest, and Survival. He is also the author of many book chapters, reports, and articles on defense and foreign policy issues, and co-edited a volume on Strategic Stability: Contending Interpretations. He has testified a number of times before Congress and the U.S.-China Economic and Security Review Commission. Colby is a recipient of the Distinguished and Exceptional Public Service Awards from the Department of Defense and of the Superior and Meritorious Honor Awards from the Department of State. A member of the Council on Foreign Relations and the International Institute of Strategic Studies, Colby is a graduate of Harvard College and Yale Law School.

All sessions by Elbridge Colby