Celeste Wallander

Celeste Wallander is an adjunct senior fellow with the Transatlantic Security Program at the Center for a New American Security (CNAS).

Wallander is a senior advisor with WestExec Advisors. She has served for 10 years as a U.S. government defense and security official, and as a leader and scholar in universities, think tanks, and foundations. She was confirmed by the U.S. Senate on February 16, 2022, and appointed by the president of the United States on February 17, 2022, as the 29th assistant secretary of defense for international security affairs, in which capacity she served until January 20, 2025. In this role, she was responsible for U.S. national security policy toward Europe, NATO, Russia, Ukraine, Eurasia, the Middle East, and Africa. She led U.S. defense policy in support of Ukraine against Russia’s invasion in February 2022, and U.S. policy on the defense modernization of NATO, culminating in the historic Washington NATO Summit on the 75th anniversary of the alliance in 2024. Previously, she served as president and CEO of the U.S. Russia Foundation (2017–2022), special assistant to the president and senior director for Russia/Central Asia on the National Security Council (2013–2017), deputy assistant secretary of defense for Russia/Ukraine/Eurasia (2009–2012), professor at American University (2009–2013), visiting professor at Georgetown University (2006–2008), director for Russia/Eurasia at the Center for Strategic and International Studies (2001–2006), senior fellow at the Council on Foreign Relations (2000–2001), and professor of government at Harvard University (1989–2000). She is the author of over 90 publications on European and Eurasian security issues, focused on Europe, NATO, Russia, and Ukraine. She received her PhD (1990), MPhil (1986) and MA (1985) degrees from Yale University and her BA (1983—summa cum laude) from Northwestern University. She is a member of the Council on Foreign Relations, the Atlantic Council, and the International Institute for Strategic Studies.