Opening Comments on How International Law Works

Let me first thank Peggy McGuinness and everyone at Opinio Juris for this wonderful opportunity to discuss my book. I also want to thank the commentators, Jeff Dunoff, Alex Geisinger, and Kal Raustiala for their willingness to participate. I know that I will benefit from the discussion. I hope that the commentators do as well, and that readers of the blog both enjoy the discussion and are encouraged to read my book!



Let me start with a few words about the methodology used in How International Law Works: A Rational Choice Theory. As the title states, the book adopts a rational choice perspective. This reflects my view that such an approach is a (but not “the”) fruitful way to think about the subject. My embrace of a rational choice methodology should not be mistaken for a dismissal of other approaches. I believe that the best way to make progress in our study of international law is to identify a set of assumptions (in this case, rational, unitary states) and see how far those assumptions take us. Proponents of other approaches, including constructivists, realists, proponents of liberal theories, and so on, are doing the right thing when they, too, state their assumptions clearly and follow where those assumptions take them. In the end our understanding of the international system will surely involve some combination of these approaches, but we cannot hope to think about a synthesis unless we understand each approach first. So my book attempts to stick with a rational choice approach, though I admit it occasionally alters those assumptions (transparently, I hope) when the world seems inexplicable under the assumption that states are rational actors.



The book aims to speak to all those interested in international law, from skeptics to traditionalists and everyone in between. The message a reader takes from the book, however, is likely to depend on his or her perspective. For traditional scholars of international law the book seeks to advance the claim that much of the discipline can be explained with a small number of fairly conventional (i.e., rational choice) assumptions. Sticking with a parsimonious set of assumptions allows us to develop tractable theories of how international works and how it might work better. For example, the theory of compliance developed in the book relies on what I call “The Three Rs of Compliance” – reputation, reciprocity, and retaliation. Understanding these forces tells us something about when states comply and why they do so. It also helps distinguish the doctrinal claim that all international law is equally binding from the predictive claim that some forms of international law (e.g., treaties rather than CIL) will tend to exert greater “compliance-pull” than others. This emphasis on theory and assumptions leads to a number of conclusions that differ from conventional accounts of international law. I argue, for example, that there is no sharp distinction between the effect of soft law and hard law; that CIL should allow for subsequent objectors as well as persistent objectors; and that states do not always want to increase, rather than decrease the credibility of their promises. So the book tries to persuade traditionalists that this sort of theoretical approach can illuminate our understanding of the field. Without denying the importance and value of detailed, fact specific inquiries into events, the point here is that it is also useful and productive to think in more theoretical terms in order to get a sense of how the system works.



The book delivers a similar message to those with constructivist views or those whose first response is to consider the specifics of institutions or domestic politics. Each of these perspectives yields very fact-specific inquiries which are often difficult to generalize. The book tries to show that a general theory of international law is possible and, indeed, necessary to understanding the system.



A very different message is aimed at skeptics of international law. I have in mind commentators who use rational choice assumptions essentially identical to those I adopt in the book – that states are rational and selfish. The book lays out a theory of international law that is consistent both with these assumptions and with a world of robust and effective international law. The discussion explains how international law can affect state conduct, why states choose to enter into international law arrangements, and why international law sometimes fails to constrain states.



Both of these messages are intended to achieve the same result, which is to strengthen the study of international law. International legal scholars have at times had difficulty answering critics because the field lacks a coherent and comprehensive theory. There are, of course, theories addressing various aspects of the subject. But I think it is fair to say that no existing theory can be applied to the full range of international law questions. The only exceptions are theories that simply assume a propensity to comply with international law, thereby dodging one of the most central questions in the field.



This book seeks to build a comprehensive theory of international law. It not only helps us to understand that field, but also strengthens the ability of international legal practitioners and academics to explain why the subject matters, and why it is an essential tool for addressing so many of the world’s problems.



The foundation of the project is a theory of international law based on the already mentioned Three Rs of Compliance. Though each of the Three Rs is important, the book devotes the most space to a discussion of reputation. The role of reputation has been familiar to political scientists (among others) for some time, but the discussion of reputation in the book moves us forward in thinking about how reputation affects international law and when reputation is likely be most (or least) effective. One example is the challenge of multilateral cooperation (e.g., climate change). Unlike retaliation and reciprocity, reputational sanctions do not suffer from free rider or credibility problems and so may be able to deliver cooperation that would not otherwise be possible. I am obviously not the first to discuss the role of reputation, but I think the book advances a more complete account of how it generates compliance, how it is accumulated, and how it can be lost.



The book then turns to look at the sources of international law, in particular international agreements and customary international law (CIL). With respect to CIL I explain how customary rules can come about and how their status as law can cause them to influence behavior. The basic idea is that once a norm comes to be viewed as a legal requirement, the stakes in terms of reputation, retaliation, and reciprocity are raised, making it more costly to ignore that rule. This mechanism allows CIL to influence behavior. If one adopts this view of CIL, however, it becomes impossible to retain the conventional definition of CIL as opinio juris and general practice. The theory states that CIL matters because other states believe that a state has a legal obligation. This means that a form of opinio juris – specifically the views of observing states – is what “creates” CIL. Practice has no relevance. So the theory tells us that we should discard the conventional definition of CIL which, in any event, is impossible to reconcile with the way CIL is often used by courts, commentators, and states. The easiest (but not the only) example is torture which is widely practiced and yet considered to be CIL. My functional theory of CIL avoids this disconnect between theory and practice.



The book also includes a chapter entitled International Agreements. The name of the chapter foreshadows one of the claims I make – that there is no stark difference between “hard” treaties and “soft law.” Rather, states select from these alternative levels of commitment, much like they select the other features of their agreements – dispute resolution, escape clauses, substance, and so on. One immediate payoff is that we can (and should) use the same models and theories to study both types of agreements. In fact, the discussion of hard and soft law is just one example of how states trade off various design features against one another. They may opt, for example, for weaker substantive provisions but a more robust form; or they may include strong substantive provisions, but also have generous exit and escape clauses. All of the features of the agreement are negotiated at once, and must be considered together.



The discussion of agreements provides an explanation of why states enter into agreements, what they hope to get, and how treaties work. It also attempts to explain many of the features of agreements, including the scope of the agreement, the depth of the agreement, the number of members, and more. Let me illustrate the style of argument by summarizing what the book says about the scope of agreements. I begin with the assumption that the transaction costs of entering into an agreement grow larger as the scope increases, and that this causes states to prefer the narrowest possible agreement. This gives us a default position – that we should expect agreements to be as narrow as possible. I then relax this assumption in three different ways to explain why we observe treaties of varying scope. First, states may broaden the scope to increase effectiveness – it makes little sense to have an agreement on tariff barriers if you do not also restrict non-tariff barriers. Second, a broader scope may be needed to construct the transfers necessary to reach a consensus. In intellectual property, for example, after years of failed attempts to get an international agreement the United States and others succeeded in getting the TRIPs agreement at the WTO because they were able to offer developing countries concessions in the form of market access and a cessation of unilateral measures. A competing view is that the United States was able to threaten developing countries with exclusion from the trading system if those countries rejected TRIPs. Though these two versions of events differ, both describe a situation in which broadening the agreement to include both intellectual property and trade allowed negotiators to transfer value in ways that generated agreement. Finally, there may be economies of scope that justify a broader agreement. If trade in goods is to be discussed at the WTO, it makes sense to also discuss trade in services as this avoids having to duplicate many of the features and functions of the WTO.



Let me very briefly return to a couple larger themes. I hope readers will come away thinking of the Three Rs of Compliance as the key forces that make international law work, and that they will have a better sense of when and how each of these functions. With respect to the sources of law, the book attempts to explain that the various ways in which legal obligations come about are different points on a spectrum of commitment. The stronger the commitment, the higher the cost of violating international law, and the stronger the compliance-pull provided. This view is quite different from the more traditional view under which treaties, soft law, customary law, and mere norms are all considered to be distinct creatures. Other boundaries also fade when we take a rational choice approach to international law. It is impossible to sustain a view of international legal commitments as being binary in the sense that states are either “bound” or they are not. Instead, we must again think in terms of degrees of commitment. A formal treaty is traditionally said to bind a state, but at times the cost of violating that commitment will be quite small. A soft law agreement is normally considered to not be “binding” and yet may have a profound effect on behavior because a failure to comply would be costly. The more one thinks about international law through a rational choice lens, the more traditional distinctions fade into differences of degree. Surrendering old categories can be uncomfortable, because one’s sense of order is disturbed, but if the field is to advance it must seek out stronger theoretical foundation, even if doing so forces us to rethink long-held views. Hopefully this book represents a step in that direction.