According to US military doctrine, legitimacy is one of the twelve principles of joint operations. But that concept—legitimacy—is a complex one. How is it defined? How should we understand the ways in which the laws of war, rules of engagement, national policies, and civilian harm mitigation measures overlap—and how they differ? How can rules of engagement and policies change in different missions, theaters, operating environments, and wars? This episode examines those questions and features an insightful discussion with an expert on the subject: Laurie Blank, a clinical professor of law at Emory University School of Law, director of the International Humanitarian Law Clinic, and author of the book International Conflict and Security Law.