The Oxford Guide to Treaties Symposium: Contractual and Institutional Elements in the Treaty Process

[Catherine Brölmann is Associate Professor of Public International Law at the University of Amsterdam]

Particular features in the interpretation of constitutive treaties or secondary acts of international organizations reflect the special nature of the law of organizations, which brings both contractual and institutional features in the treaty process.

Following up on posts of Richard Gardiner, who brings up pertinent questions regarding treaty interpretation that are not addressed by the VCLT, and Geir Ulfstein, who points at the increasing publicness of international law ia through the creation of treaty bodies, this post briefly focuses on a phenomenon that is not covered by the Vienna Convention on the Law of Treaties and strictly speaking not by the law of treaties as such. This is the mixing of contractual and institutional elements in international treaty practice.

The Guide to Treaties addresses what is arguably a specific aspect of this combination of contractual and institutional elements, with a chapter on the interpretation of constitutive treaties and acts of international organizations. We find two trends in the interpretation of constitutive treaties or ‘law of the organization’ in general, that stand apart from the standard interpretive approaches in the Vienna Convention: a ‘teleological approach’ to the text, not very common in regular treaty interpretation but akin to traditions in national law of statutory interpretation in an organic, constitutional context; and particular importance attached to the ‘practice of the organization’ as opposed to the practice of the original treaty parties (such accompanied by a corresponding disinterest for the travaux préparatoires and the intention of the original parties).

The claim is that this ‘constitutional’ approach to the law of the organization can be traced to the notion of that law as special and ‘self-contained’ – not in the traditional sense of a particular area of substantive law or lex specialis, but rather as a semi-independent or internal legal order based on specific institutional rules. Constitutive treaties of organizations in fact have been attributed something of a constitutional character (cf the ICJ in 1996), binding member States to a set of coherent internal laws on the organization’s competences, functions and goals. The special character of the law of the international organization as as an internal legal order, semi-closed off from general international law, is also recognized by the Vienna Convention: think for example of the general reservation clause in Article 5, and the role for the competent IGO organ in the acceptance of a reservation provided for by Article 20(3).

The mix of contractual and institutional features which consequently marks the international organization as a legal environment is visible in more areas of treaty practice than just interpretation. The use of an institutional infrastructure for international processes dates back to the mid-nineteenth century, but recent decades show international organizations using in a particularly efficient and self-confident way their institutional mechanisms in order to streamline stages in a treaty-making or law-making process that were traditionally based on individual consent of the contracting parties – for example in the adoption of the text (UNGA), the initial signature subject to ‘ratification’ (ILO) or the inclusion of a treaty text in a binding resolution (UNSC).

This phenomenon falls outside the scope of the VCLT in a very fundamental way, as it moves in and out of the law of treaties framework altogether. In that respect it is different from new trends such as evolutive interpretation or ‘living instrument doctrine’ -, which may be unaddressed by the Vienna Convention, but which are considered to be within the law of treaties paradigm. On the other hand, in the case of interpretation of IGO law, a preliminary question arises as to the applicability of the Vienna Convention to begin with. Are UN Security Council resolutions a form of treaty law or do they amount to ‘international legislation’? Was the 1999 new ‘strategic concept’ of NATO a living instrument interpretation of the 1949 North Atlantic Treaty or a redefinition of powers and competences by an Organization making use of its compétence de la compétence to enact institutional innovation?