The Oxford Guide to Treaties Symposium: The Public Character of Treaty Law

[Geir Ulfstein is Professor of Public and International Law at the University of Oslo]

Treaty law is increasingly acquiring a public character. One reason is that more and more treaties set up treaty bodies, i.e. organs that are neither formal international organizations nor international courts. Examples are the Conference of the parties (COPs) used in international environmental law, the Antarctic Treaty Consultative Meeting, or the supervisory organs established by human rights treaties, such as the Human Rights Committee.

These bodies may exercise public powers in the form of law-making, executive decisions or enforcement. Treaty law is essential for their creation. But treaty law must interact with international institutional law when it comes to determining the powers of the treaty bodies, as well as the legal status and effects of their decisions. With public powers comes also issues of the effectiveness and legitimacy of their activities.

The law-making powers of treaty bodies represent a move away from ad hoc consensus-based treaty-making. These bodies are permanent fora that may be tasked with law-making. Examples are COPs in environmental treaties empowered to adopt new protocols, such as the Kyoto Protocol, i.e. the adoption of formally new treaties. But some of these treaty bodies provide for their COPs to adopt or amend annexes to the treaties or protocols, subject to the non-acceptance of these decisions by individual states parties. By requiring action by states in order for them not to become committed rather than to become committed – opting out, instead of opting in – the efficiency of law-making is greatly enhanced.

Other examples are the ‘quasi-legislative’ powers of the UN Commission on the Limits of the Continental Shelf to adopt recommendations on the outer limit of the continental shelf that according the Law of the Sea Convention will, if implemented by the coastal state, be ‘final and binding’. Similarly, the ICC Assembly of States Parties has the power to adopt and amend ‘elements of crime’ which shall ‘assist the Court in the interpretation and application of Articles 6, 7 and 8 bis’ (genocide, crimes against humanity, war crimes and the crime of aggression), subject to the condition that such elements ‘shall be consistent’ with the Rome Statute.

In determining the powers of the treaty bodies the traditional canons of treaty interpretation apply, including the principle of effective interpretation. But it may also be a question of the applicability of international institutional law, especially the principle of implied powers. This principle has for example been invoked in relation to the powers of the Human Rights Committee to adopt General Comments, interim measures, as well as follow-up measures.

The legal status of the treaty bodies’ decisions may also raise difficult questions. For example, article 17 of the Kyoto Protocol enables the Meeting of the Parties to adopt ‘rules’ relating to the operation of the system for trading in emissions of greenhouse gases. It is not entirely clear whether such rules are legally binding. But even if the treaty bodies are not empowered to make binding decisions, such decisions are not necessarily without legal significance. Article 31(2)(b) of the Vienna Convention on the Law of Treaties requires that treaty interpretation takes into account ‘any subsequent practice in the application of the treaty which establishes the agreement of the parties regarding its interpretation’. The practice of the treaty bodies should be seen as international institutional practice rather than the practice of states parties – especially if the treaty bodies are composed of independent experts. But responses by states practice may establish an interaction between such institutional practice and that of states parties.

Treaty bodies may also have important functions in supervision and enforcement of treaty obligations – complementing treaty law and the law of state responsibility. Examples are the supervisory bodies in human rights, international environmental law and disarmament law. But, again, it may be difficult to determine the legal status of enforcement decisions. This is illustrated by article 18 of the Kyoto Protocol establishing that mechanisms ‘entailing binding consequences shall be adopted by means of an amendment to this Protocol’. It is not obvious what kind of measures should be regarded as entailing ‘binding consequences’, but it would be difficult to accept e.g. deduction of emissions quotas at a penalty rate, as adopted by the MOP as part of its Marrakesh Accords, without a treaty basis in the form of an amendment.

It may be concluded that treaty law is necessary, but not sufficient to understand the legal aspects of treaty bodies and their activities. Treaty law must be complemented by international institutional law. This branch of international law is characterized by its open-ended nature, and has sufficient flexibility to be adapted to the specific functions of treaty bodies.