International Law and International Relations: Together, Apart, Together?

In 1982, I edited a volume on international regimes, a term that was just coming into wider usage in the field of international relations and which had some currency in international law.1 Most of the contributions to the volume, which dealt with a number of specific areas such as trade and finance, as well some more general theoretical explorations of the concept of regimes, were written by political scientists. The conference that preceded the publication of the volume, however, was attended by international lawyers and economists, as well as political scientists. For me, the conference illuminated a distinction that I had not fully appreciated between social scientists, the economists, and political scientists, on the one hand, and international lawyers on the other. The lawyers actually knew something, knew a great deal, about the specific character of international regimes, such as the rules of the General Agreement on Trade and Tariffs ("GATT"). The economists knew hardly anything at all. The discussions at the meeting, however, were dominated by the economists and political scientists. Now, perhaps this was simply because the lawyers were wise enough to realize that Palm Springs in the winter was better appreciated without spending an excessive amount of time ruminating about a concept as abstract as international regimes. It was evident enough that the political scientists did not have any real understanding about how the term should actually be understood! My own conclusion, however, was that the lawyers approached the issue of regimes in a fundamentally different way. The political scientists and economists were interested in formulating propositions that could be empirically tested. To some extent, they also shared a common explanatory, as well as methodological, frame. Whatever the international lawyers were doing, and I for one was not sure, was different. The study of international law and international relations has not always been so sharply distinguished. Until the 1970s and even later, international law would have been part of the curriculum of almost all international relations programs. In 1947, some of the founding members of the editorial board of the journal International Organization, the venue where issues that are of concern to public international lawyers would most frequently be addressed in the international relations literature, were international lawyers who also taught in political science departments or international relations programs. The break came because of changes in the study of international relations, rather than in the study of international law. Following political science more generally, international relations scholars became more self-consciously social scientific. Since the 1970s, the study of international relations has been driven by a set of theoretical frameworks that have generated more specific research programs or theories.3 Realism, which existed as a general frame of reference and even a set of normative prescriptions long before the 1970s, has been the most prominent of these approaches. Its most acclaimed post-war exponent, Hans Morgenthau, was a refugee from Nazi Germany appalled by what he saw as the consequences of ignoring the distribution of power as the basic determinant of outcomes in the international environment. Morgenthau, like his contemporaries, was more of an essayist than someone who tried to systematically associate explicit propositions with empirical evidence. While Morgenthau emphasized the importance of the distribution of power among states, he also pointed to human nature as a basic cause of conflict, and distinguished between states following status quo and imperialist policies.4 It was not evident what weight Morgenthau gave to the nature of human beings, the domestic characteristics of states, or the international distribution of power. In 1979, Kenneth Waltz published Theory of International Politics,5 in which he made a clear distinction between systemic and domestic, or what he called reductionist, arguments. …