The relationship between the military and the society it serves has a significant impact on policy decisions and even budgets. The veneration of service members in the United States today manifests benignly in the refrain, “Thank you for your service,” and the much appreciated discounts at the local home improvement center, but this reverence can also have less benign effects. The number of retired flag officers serving in high government positions, sitting on the boards of defense contractors, and appearing as talking heads on television shapes policy, which in turn drives Pentagon budgets. Dr. Steele Brand, a professor of history at The King’s College in New York City, explored the differences between the citizen-soldier and the soldier-citizen in his recent book, “Killing for the Republic.”Republican Rome produced highly adaptive armies with farmers who would moonlight as effective soldiers during the campaigning season and then return to their families and plows—a practice that helped to remove the barriers between the military and the society it served, according to Brand. He says Rome’s part-time soldiers faced an uphill battle against enemy professionals, but that their ability to adapt meant they usually prevailed in the end. In this interview, Dr. Brand explains the differences between the Roman and American models of training soldiers and how those differences contribute to the civilian-military divide.