International Legal Theory Gets Rational and Empirical

At first glance, the last thing international law scholarship needs is more theory. Yet, while there is plenty of IL theory, in some ways IL theory is relatively undeveloped. Most importantly, until recently, IL theory was unaffected by the rational-choice juggernaut that swept almost every other discipline, including IL’s sister discipline of international relations.

But rational choice has arrived with a vengeance, as Eric Posner and Jack Goldsmith’s recent book, The Limits of International Law, demonstrates in developing a rational choice approach to explaining both customary international law and treaties. Oona Hathaway, who comes to quite different conclusions about IL compliance than Eric Posner, also draws on rational choice assumptions in her most recent article Between Power and Principle: An Integrated Theory of International Law, although her theory “disaggregates” the state to focus on the importance of domestic institutions (a point Chris argued here).

Hathaway is also known for her reliance on empirical studies to buttress her claims, as Peggy explained here. The increasing importance of empirical methodologies can be illustrated in Andrew Guzman and Beth Simmons’s recent article Power Plays & Capacity Constraints: The Selection of Defendants in WTO Disputes, which conducts an empirical study of WTO disputes to conclude that the “capacity” (e.g. the ability of a country to develop the trade litigation expertise) is more important than the relative poverty of the country in determining whether it will bring claims against more powerful and wealthy states in the WTO system.

In any event, it is hard to resist concluding that IL theory (at least in the U.S.) is trending inexorably toward rational choice assumptions, game theory models, and sophisticated empirical research.