Hans Morgenthau, the great U.S. theorist of international relations, wrote that the key to the discipline was simple: Just assume that “statesmen think and act in terms of interest defined as power.” Doing so, he implied, would unlock timeless and universal laws.
When it came to power in pre-modern Europe, Morgenthau and other IR theorists zoomed in on war and conflict, and the mistrust that resulted. They saw in these patterns of recurrent war a grim warning for any sort of attempts to improve international politics today. But their attempt to find simple lessons of history is complicated by the fact that the actual levers of power amid Europe’s dynasties were often very different: marriage, sex, and family.
