  Political realism is usually contrasted by IR scholars with idealism or liberalism, a theoretical perspective that emphasizes international norms, interdependence among states, and international cooperation. The “Melian Dialogue,” which is one of the most frequently commented-upon parts of Thucydides’ History, presents the classic debate between the idealist and realist views: Can international politics be based on a moral order derived from the principles of justice, or will it forever remain the arena of conflicting national interests and power?