According to Isaacson and Thomas (Chapter 19), during Joe McCarthy's rampage through the State Department looking for Communists and other undersirables, one of Dulles's subordinates, responsible for internal security, being "vindictive and shrewd, hired 350 zealous but inexperienced investigators who quickly went to work ferreting out Foreign Service officers deemed drunkards, homosexual, incompetent, or 'incompatible,' a flexible category. They were replaced by true believers."