Melissa Dalton is Performing the Duties of Deputy Under Secretary of Defense for Policy.

Melissa Dalton was sworn in as the Assistant Secretary of Defense for Homeland Defense and Hemispheric Affairs on March 4, 2022. She is responsible for advising the Secretary of Defense and other senior defense leaders on defense continuity and mission assurance; homeland defense and defense support of civil authorities; Arctic and global resilience; and U.S. defense and security policy for Canada, Mexico, Central America, the Caribbean, and South America.

Prior to being sworn in as the Assistant Secretary of Defense for Homeland Defense and Hemispheric Affairs, she served as the Principal Deputy Assistant Secretary of Defense for Strategy, Plans, and Capabilities from January 2021 to March 2022. In that role, she was responsible for advising the Secretary of Defense and other senior defense leaders on national security and defense strategy; the forces, contingency plans, and associated posture necessary to implement the defense strategy; nuclear deterrence and missile defense policy; and security cooperation plans and policies. Previously, Ms. Dalton was a senior fellow and deputy director of the Center for Strategic and International Studies (CSIS) International Security Program and director of the Cooperative Defense Project. Her CSIS research focused on reinforcing the principled foundations of U.S. defense strategy and military operations. Prior to joining CSIS in 2014, Ms. Dalton served for a decade as a career civil servant in the Bush and Obama Administrations at DoD. Her assignments included senior advisor for force planning, special assistant to the Under Secretary of Defense for Policy, policy adviser to the commander of the International Security Assistance Force in Kabul, Afghanistan, and country director for Lebanon and Syria in the Office of the Under Secretary of Defense for Policy. She also served as an intelligence analyst at the Defense Intelligence Agency.

Ms. Dalton holds a B.A. in foreign affairs from the University of Virginia and an M.A. in international relations from the Johns Hopkins University School of Advanced International Studies. She is a member of the Council on Foreign Relations and was a Council on Foreign Relations International Affairs Fellow.