This chapter offers a new framework for theorizing about the roles of different types of actors who participate in processes of cross-fertilization. All of these actors have complex or mixed motives: while actors may place some value on the coherence of the international legal system, they weigh such systemic concerns against other, more immediate concerns. International judges, for example, may place value on the coherence of the international legal system, but they may place greater emphasis on the autonomy of their own specialized or regional legal order, on the normative values of that order and on their own authority within that order. Other actors, by contrast, may place little or no value on international legal coherence, but favor or oppose cross-fertilization as a function of its effect on the their likelihood of prevailing in a dispute. In a world of complex actor preferences, the process of cross-fertilization is likely to resemble, not a consensual process of management, but a constant struggle among a wide variety of actors, some of whom will champion cross-fertilization while others seek to prevent or limit it.

This introduction reviews scholarship on international legal fragmentation, lays out a framework for understanding international judicial cross-fertilization, and previews the contributions and their findings. Existing scholarship on international legal fragmentation, we argue, has moved through three phases over the past several decades. In the first, legal scholars and practitioners reacted with alarm to the judicial proliferation of the post–Cold War years, which they feared would create overlapping jurisdiction and conflicting interpretations of law. Following this period, the new century saw the pendulum swing toward a second, more optimistic picture in which international courts addressed fragmentation through “management” techniques, producing unity in international law. We can detect the opening salvos of a third wave, as skeptics have questioned the management account, pointing to the mixed motives of international judges and the limits of cross-fertilization. In this volume, we build on the existing literature by theorizing the actors of cross-fertilization and their motives, and by distinguishing between procedural and substantive cross-fertilization.

This chapter provides an account of ways that experimental methods can be used to uncover and identify decision-making biases. Investment arbitration tribunals derive their legitimacy from different normative, sociological and political processes than standing courts. In great part, these tribunals rely on tacit norms of behaviour among arbitration professionals. Understanding what factors affect how arbitrators make decisions in these kinds of adjudicative settings is essential in assessing critiques concerning the quality or correctness of their decisions and especially their independence and impartiality. The authors describe a promising alternative empirical strategy that utilizes survey experiments conducted on arbitration professionals to test bias claims. It discusses also how researchers can design experimental vignettes to mimic specific aspects of the arbitration process that are difficult to observe or manipulate in the real world context.

This book has its origins in a seminar which took place on 6–7 May 2015 at Tillar House, the headquarters of the American Society of International Law in Washington, DC. The title of the seminar, which was organized under the auspices of the International Legal Theory Group of the American Society, was “Whither the West? Debates on Concepts of International Law in Europe and America”. As organizers, our purpose was to gather a group of scholars based in Europe and North America to reflect on the state of the field, both in a general sense and in relation to specific issues.

European countries are seen as strong supporters of international adjudicatory institutions related to human rights and international criminal law, while the USA has generally been more skeptical about international courts and tribunals. While positions of the USA and Europe have generally been similar in relation to tribunals examining issues to trade and investment, for example. More recently and especially since the election of President Trump, the USA’s position towards all international courts and tribunals, including on matters of international economic law. The election of President Trump has resulted in a profound antagonism towards international courts and tribunals, and multilateral institutions more generally, in both words and facts. Differently, European countries, guided in large part by the European Union, have broadly maintained their support for international courts and tribunals, including trade related courts, and have voiced their desire for substantial changes in investor-state dispute resolution mechanisms. In both cases, European countries have not tried to dissociate from those courts, but rather, have argued for stronger, clearer and more permanent dispute resolution mechanisms.