[3] Ruger earned a Bachelor of Arts degree from the College of William & Mary and a PhD in politics from Brandeis University.

Ruger fought in the War in Afghanistan as a member of the United States Navy Reserve.

[4][5] Ruger worked as a professor of political science at Texas State University and the Lyndon B. Johnson School of Public Affairs.

[9] In September 2020, Ruger was nominated by President Donald Trump to serve as the United States Ambassador to Afghanistan.

[10][11] On January 3, 2021, his nomination was returned to the President under Rule XXXI, Paragraph 6 of the United States Senate.