William Ruger is research fellow in foreign policy studies at the Cato Institute; he is an assistant professor in the Department of Political Science at Texas State University. As well, he is researcher on international relations, U.S. foreign policy, and civil-military relations. Previously, Ruger was a Fellow at Liberty Fund and also taught at Wesleyan University and Brigham Young University.

Ruger is coauthor of Freedom in the 50 States and the book review editor for Armed Forces and Society. He earned his PhD in Politics from Brandeis University and an AB from the College of William and Mary.