Elbridge A. Colby is the U.S. Under Secretary of War for Policy (confirmed April 2025). He is a career national‑security policy professional who previously served as Deputy Assistant Secretary of Defense for Strategy and Force Development (2017–2018), was a lead architect of the 2018 National Defense Strategy, co‑founded the Marathon Initiative think tank, and authored The Strategy of Denial. He holds a BA from Harvard and a JD from Yale and has worked across DoD, State, and the intelligence community.