To look at the present, it pays to study the past. No past conflict is more foundational to the field of international relations and security studies than the Peloponnesian War. The Peloponnesian War (431 BCE - 404 BCE) was fought between Greek city-states Athens and Sparta. Why is this conflict so studied 2500 years after it took place? We sit down with Doctor John H. Maurer to deduce the modern relevance of the Peloponnesian War. We discuss how the Peloponnesian War is one of the first examples of many modern security problems, including coalition warfare, ideological conflict, and long-range expeditionary operations.