Thomas Joscelyn is an American counterterrorism expert, terrorism analyst, economist, and writer. He holds a Bachelor of Arts in Economics from the University of Chicago. His career includes serving as Senior Fellow at the Foundation for Defense of Democracies (FDD) and Senior Editor (and founder) of FDD's Long War Journal; Senior Fellow at Just Security (since April 2024); Executive Director of the Center for Law and Counterterrorism at FDD; Senior professional staff member on the House Select Committee to Investigate the January 6th Attack on the U.S. Capitol, where he was the principal author of the final 814-page report (published December 22, 2022); trainer for the FBI Counterterrorism Division; senior terrorism adviser for Rudy Giuliani's 2008 presidential campaign; and testifying before Congress more than 20 times on counterterrorism and foreign policy issues. His publications include What President Obama Doesn't Know About Guantanamo (2010, Encounter Books), Iran's Proxy War Against America (Claremont Institute), and Enemies Near and Far: How Jihadist Groups Strategize, Plot and Learn (2022, Columbia University Press, co-authored with Daveed Gartenstein-Ross). His work has appeared in The New York Times, The Wall Street Journal, Politico, The Dispatch, The Weekly Standard, National Review, and others. He has appeared on CBS 60 Minutes, CNN, Fox News, MSNBC, and others. Social media: X/Twitter (@thomasjoscelyn), Bluesky (tomjoscelyn.bsky.social).