Thomas is a Senior Fellow at the Foundation for Defense of Democracies. He is a terrorism analyst and writer living in New York. Most of Thomas's research and writing has focused on how al Qaeda and its affiliates operate around the world. He is a regular contributor to the Weekly Standard and its online publications, the Daily Standard and Worldwide Standard. He is the Senior Editor of The Long War Journal. His work has also been published by National Review Online, the New York Post, and a variety of other publications.

Thomas is the author of Iran's Proxy War Against America, a short book published by the Claremont Institute that details Iran's decades-long sponsorship of America's terrorist enemies. He makes regular appearances on radio programs around the country and has appeared on MSNBC.

Thomas served as the senior terrorism adviser for Mayor Giuliani's 2008 presidential campaign. In 2006 he was named one of the Claremont Institute's Lincoln Fellows. He holds a B.A. in Economics from the University of Chicago.