ABSTRACT
International relations theory is constrained by the fact that history provides a poor substitute for a laboratory. In world politics, a relatively small number of states play major roles, along with many other entities that seek to influence events. Even if one focuses on state behavior, one is confronted by few independent events and by multiple causes of behavior at different levels of analysis. Furthermore, strategic interaction is inherently indeterminate, and states often have incentives to deceive observers. To use an analogy from another social science, multiple causality makes some aspects of international relations more like macroeconomics than like microeconomics, and strategic indeterminacy means that the relevant analogy in microeconomics would be the troubled area of oligopoly theory. Moreover, most theorists of international relations suffer from being in the
middle of events, rather than viewing them from a distance. Thus it is not surprising that international relations theory has always been strongly affected by current political concerns. This is true even for the Realists with their parsimonious efforts to state eternal truths. Thucydides, the founding father of Realism, presented a structural account of the origins of the Peloponnesian War in part because of the lessons he wished to teach his fellow citizens.1 When Hans J. Morgenthau wrote his post-war classic, Politics Among Nations, he was clearly intent on instructing his fellow citizens about the importance of avoiding the idealist and isolationist fantasies of the interwar period. Even the neorealist structural theories of Kenneth Waltz can best be read as exhortations to policymakers and fellow citizens about how they ought to respond to the structure of power rather than as accurate accounts of how the two superpowers behave.
