John Drennan

John Drennan is a Non-Resident Fellow at the Transatlantic Dialogue Center, supporting TDC research and initiatives focused on U.S.-EU-Ukraine defense and security issues. 

He is a Senior Policy Analyst at RAND Corporation, where he conducts research on U.S. defense policy, European security, and nuclear strategy and arms control. 

From May 2024-May 2025 he was detailed to the U.S. Department of Defense via the Intergovernmental Personnel Act (IPA), serving in the Office of the Under Secretary of Defense for Policy as a Ukraine Country Director. 

He has an MA in Strategic Studies and International Economics from Johns Hopkins-School of Advanced International Studies (SAIS) and a BA in Political Science, Economics, and International Studies from Case Western Reserve University.