If you haven't checked this book out yet, you really should. There has been an evolving debate in international legal scholarship about the place of rational choice theory in international law. Jack Goldsmith and Eric Posner make a very strong argument that, if nothing else, the views of rational choice theorists must now be taken into account in any theory of international law. For those unfamiliar with "rational choice", it is a theory that starts with a premise that states act rationally to maximize their own interests. It has often been used in political science work, but has, until recently, been underutilized in international law. Instead of focusing on legitimacy mechanisms (Franck) or norm internalization (Koh), the authors find that the compliance question of international law is simple. The conclusion reached by Goldsmith & Posner is that states follow international law when it is in their interests to do so.
American international law scholars have been debating and arguing over the views of the likes of Goldsmith / Curtis Bradley / Posner and John Yoo for awhile, but I think its time for European scholars to stop simply dismissing their views and attempt to either invalidate them or explain their deficiencies. For instance, the classic European views on customary international law, based in practice and opinio juris are taken so for granted that they are rarely challenged anymore. Instead, it seems that most scholars feel that acknowledging the weaknesses of these concepts does not require them to explain these weaknesses or how they affect the functioning of international law generally. In "The Limits of International Law" Goldsmith and Posner boil down the functionality of international law into four categories: coincidence of interest, coercion, coordination and cooperation. These categories explain nearly all the functioning of international law that takes place.
I imagine that coercion and coincidence of interest are self explanatory. Coordination is describes circumstances where states are more interested in creating a rule that governs their behavior rather than the substance of the rule itself. Cooperation occurs where states reciprocally refrain from activities that would otherwise be in their immediate or short-term self-interest in order to reap larger medium- or long-term benefits.
Ultimately, Goldsmith and Posner argue, international legal compliance flows from these self-interested motives rather than a vague notion of opinio juris or norm internalization.
There is a draft of many of their ideas in the book and I challenge my co-bloggers (or any other commentator) to refute them. My point is not that these ideas are infallible, but that they are much stronger than you might think.