The Peloponnesian War was also the first great instance where Western powers turned on each other. Their common commitment to rationalism, civic militarism, and constitutional government resulted not just in high culture but also in lethal militaries that could square off in mutual destruction. So Athens versus Sparta serves as a warning—centuries before the Roman Civil Wars, Cold Harbor, the Somme, and Dresden—of what can happen when the Western way of war is unleashed upon its own.
