Book excerpt: What are the independent variables that determine success in war? Drawing on 40 years of studying and teaching war, political scientist Christian P. Potholm presents a 'template of Mars, ' seven variables that have served as predictors of military success over time and across cultures. In Winning at War, Potholm explains these variables--technology, sustained ruthlessness, discipline, receptivity to innovation, protection of military capital from civilians and rulers, will, and the belief that there will always be another war--and provides case studies of their implementation, from ancient battles to today.