The Many Methods of International Legal Scholarship

The increasing use of empirical research in international legal scholarship is a good thing, as Julian noted. Empiricism (or at least an attempt at empiricism) brushes away the cobwebs of musty “givens” and unpacks old assumptions that have been tucked away. By bringing in new data to test academic doctrines, empiricism can do a good job helping theory be more descriptive of (and useful to) practice.

Rational choice theory, however, is merely one menu option among many theoretical world views on how to interpret the data that is generated. I think it is also a good thing that international lawyers are deploying the techniques of rational choice theory, but, as with other theories, it is only one particular approach, with its own set of assumptions and flaws.

For example, prior to publishing The Limits of International Law, Eric Posner and Jack Goldsmith wrote an article entitled A Theory of Customary International Law, which provided a game theoretic appraisal of customary international law. They found that much of what may has been considered customary international law may be no more than the opportunistic actions of states. In his article “Game Theory and International Law: A Response to Professors Goldsmith and Posner” (23 Michigan Journal of Int’l Law 143 (2001)), Mark Chinen, also applying game theory, came to a different set of conclusions, arguing, among other things, that although game theory can be used to explain why states do or do not cooperate, “game theory has nothing to say about whether customary international law is a valid theory of law.” Both articles used rational choice theory, yet in the hands of different authors, the results are quite different.

Similarly, Eric Posner and John Yoo used rational choice arguments as a basis for a critique of Anne-Marie Slaughter and Larry Helfer’s “Toward a Theory of Effective Supranational Adjudication.” Some of their results, though interesting, are counter-intuitive, such as their conclusion that it is preferable to have single arbitrators rather than the standard three-person panel. Their reasoning is that a single arbitrator is more susceptible to retaliation or sanction by the parties in the arbitration, therefore the arbitrator is incentivized to give a neutral judgment.

Perhaps this conclusion holds water theoretically; it flies in the face of the result of the choices of actors in the actual “arbitration market,” though. High-stakes commercial and public international arbitrations are usually multi-person panels. If we place a certain faith in the choices of actors in the market for arbitrations, then why do the rational choices of the actual market clash with Posner and Yoo’s prescription? Clearly, something else is at play, perhaps in the way in which rational choice theory is being deployed.

This is the crux of Slaughter and Helfer’s rejoinder. Among a wide variety of theoretical, methodological, and empirical critiques of Posner and Yoo’s article, they note a “selection bias” in which certain types of tribunals were under-represented, “omitted variable bias” in which crucial factors such as the subject matter that tribunals were able to hear and the power differential among states, were not taken into account.

And these criticisms don’t even consider the broader questions as to whether game theoretic models adequately model decision-making or whether they under-value key variables (ideology, emotion, misperception, among others). See William Poundstone’s The Prisoner’s Dilemma for a fascinating history of the uses and abuses of game theory in foreign policy decision-making.

All this debate over how rational choice theory may be applied to international law is, I think, quite healthy for international legal scholarship, but we should not let it obscure the variety of different analytic methods that exist. The Symposium on Method in International Law, published in 93 American Journal of International Law 291 (1999), and following, is an excellent survey of different methodological schools. (Available at JSTOR, subscription required). Theories from each school are then applied to a common problem so that readers can see how the different assumptions and foci of each methodology plays out over the course of analysis. Similarly, Oona Hathaway and Harold Koh’s new reader Foundations of International Law and Politics is a great place to explore the multiple intersections of international law and international relations theory. Selections include major articles on realism, institutionalism, and liberal theory, as well as on constructivism, legitimacy theory, and legal process theory. These perspectives are then applied to a series of topics ranging from international trade to human rights, environmental policy to humanitarian intervention, to name a few.

Taken together, the theoretical options and challenges to the academic international lawyer are broad and varied. Rational choice theory is a relatively new entrant and it has much promise and is exciting. It is another tool in the theoretical toolbox. With time, we will get a better sense of where it is useful and where it is less successful than other theories in analyzing international law. The Hathaway and Koh book and the AJIL Symposium are good places to survey some of the many other theoretical approaches.