The International Law Commission’s Conclusions on the identification of customary international law show that contemporary international law grant a modest role to international organisations as independent actors in the formation of customary international law, which is remarkable, given that organisations participate ever more fully in international legal affairs. One of the reasons for such a restrictive approach lies in the hesitation of the Commission to ascribe to international organisations a ‘juridical will’. In this chapter, this term is a shorthand for the various subjective, intentional states that systems of law project onto legal participants in order to operationalise legal agency. It shows that international law can accomodate States in this respect, but remains adverse to international organisations. This can be explained through the organisation’s functional and mechanical identity in international law, which has persisted even after organisations emerged as prominent independent legal actors. It is submitted that this is one reason why the ascertainment of an organisation’s opinio juris, or of an organisation’s distinct will in the attribution of practice, may pose a challenge. The chapter proposes that, in light of their current role in global affairs, international organisations assume a role in the formation of custom insofar as this is substantively relevant for their work, and that organisations be understood as the receptacle of a juridical will.

This chapter proposes a theoretical framework for the role of international organizations in the formation of customary international law that rejects their traditional conceptualization as double-faced entities. Under this paradigm, organizations are either considered as fora for the development of the practice and the opinio juris of States, or as independent actors that autonomously contribute to the formation of customary international law. The aim of the chapter is to describe an alternative framework to reconcile these two faces of the same coin. It will be shown that one approach does not exclude the other, and the adoption of one perspective is only motivated by specific purposes that do not rule out the relevance of the other view. The chapter first describes the either/or paradigm in order to read the work of the International Law Commission and of the International Court of Justice. Later, it describes three ‘anomalies’ of this paradigm that concern the development of so-called ‘objective regimes’ (section 3). Finally, section 4 builds a theoretical framework on the role of international organizations in the formation of customary international law that acknowledges their dual (and not double) nature.

decommissioning; George Mitchell; Good FridayAgreement/GFA; Mo Mowlam; Ian Paisley; DavidTrimble; Tony Blair; Bertie Ahern; Gerry Adams; JohnHume

The debate over which actors contribute to customary international law generally centres on international organizations and other non-State actors, and easily accepts States as the only relevant actors. However, on rare occasions States can be governed by an international organization. When an international organization becomes entangled with a State government, the normal participation in the formation of customary international law becomes confused. A survey of practice citing to the acts of international territorial administrations shows that it is possible for these governance arrangements to contribute to customary international law in the same manner as states, even though those acts are formally undertaking by an international organization. However, their evidentiary value might be less persuasive than the practice of states.

This chapter shows that the dominant approach to custom-forming has remained adverse to the idea that international organizations and non-State actors contribute to the formation of customary international law. This orthodoxy promotes an image of these actors with which we, and the subsequent contributors to this volume, engage. From the perspective of the dominant approach, international organizations are often understood as having very restricted formal participation in the formation of customary international law. More generally, this traditional perspective holds that international organizations and non-State actors only have an instrumental or merely accidental participation in custom-formation. In some variants of this perspective, the role of non-State actors in custom-formation is even denied. This dominant approach offers a convenient starting point for this discussion attempted in this volume. It simultaneously provides a sounding board for reflecting anew on the possible ways in which international organizations and non-State actors can be seen as contributing to the formation of customary law. This chapter also introduces the contributions in this volume and comments on the suggestions that the process of formation of customary international law be understood beyond the static, formal rule-making framework.

With an emphasis on the role of international organizations and non-State actors to the formation of customary international law, this chapter recalls some of the key choices made by the International Law Commission in its work on the identification of customary international law. In doing so, this chapter offers some reactions to a number of criticisms made by international legal scholars, including some of the contributors to this volume.

This chapter delivers an account of the way in which the engagement between States and the United Nations human rights treaty bodies plays a clear, but often overlooked, role in shaping customary international law. It proceeds from the accepted notion that international organisations contribute to international law-making in a number of ways. It argues that the responses by States to human rights treaty body interpretations support a conclusion that treaty bodies can, and do, contribute to the development of customary international law through their relationships with States parties. As a starting point, this chapter delivers an account of the treaty bodies as primary interpreters of human rights treaties and contributors to the development of human rights law followed by consideration of the prohibition against torture as a human right that is also recognised as a customary rule of international law. While it is clear that the core prohibition against torture is undoubtedly recognised in customary international law, the analysis demonstrates that further dimensions of the prohibition reflecting treaty body interpretations are on the horizon.