The Toughest Military Schools in the U.S. — Quick Answer The toughest military schools in the U.S. are ranked below by overall difficulty, attrition rate, and training demands: Pararescue School (U.S. Air Force) — highest attrition rate of any U.S. military school U.S. Army Special Forces Selection and Training — up to two years of training, including ROBIN SAGE BUD/S — Navy … [Read more...] about Which are the Toughest Military Schools?