substance of the workshop

Interpretation is ubiquitous in legal thought and practice. In international law, the law and method pertaining to the process of interpretation continues to generate rich debates amongst legal scholars and to pose perplexing questions in international legal practice. From a conceptual viewpoint, the approach of the Vienna Convention on the Law of Treaties (‘VCLT’) reflects the premise that interpretation is, or at least can be, a formal process based on legal rules. This approach to interpretation has implications, which invite further exploration. First, rules of interpretation, much like any other rule of international law, are amenable to evolu-tion by being themselves subject to interpretation, modification, or displacement by other rules of interpretation. Second, rules of interpretation constitute essentially normative instru-ments serving certain normative goals. These goals or considerations may change through time or differ in whole or in part between the rules that are subject to interpretation having thus a decisive bearing on the emergence, content, and evolution of rules of interpretation in international law. 

Against this background, whilst the VCLT rules are increasingly accepted and relied upon by international courts and tribunals, this does not mean that the law on treaty interpretation is static. The internal relationship between the different elements of the rule of interpretation under the VCLT and the external relationship of the rule of interpretation under the VCLT with other methods, maxims, or special rules of treaty interpretation continue to pose vexing theoretical and practical questions. In fact, the law of treaty interpretation is still undergoing a process of refinement and progressive development. Most conspicuously, in 2018, the International Law Commission (‘ILC’) completed its work on ‘Subsequent Agreements and Practice in Relation to the Interpretation of Treaties’. The ongoing work of the Study Group of the International Law Association on the ‘Content and Evolution of the Rules of Interpretation’ is a further attestation to the continuing relevance and dynamism of this area of law. In light of these developments, this workshop intends to take stock of the ways in which the law on treaty interpretation has evolved since the adoption of the VCLT. More importantly, it aims to map out the challenges that still lie ahead in this specific area of law. 

In parallel, broader developments with respect to the law relating to the sources of international law call for a more careful evaluation of the role of interpretation of international law beyond treaties. Notably, the ILC completed recently its work on the ‘Identification of Customary International Law’, whereas its work on ‘General Principles of Law’ is still ongoing. It is still an open question whether there is space for the development of rules of interpretation in that context. To illustrate this point, the ILC’s conclusions on customary international law are largely agnostic as to the process of determining the content of customary rules whose existence is undisputed. This approach can be contrasted with the ILC’s previous work on unilateral acts of states in which it provided explicit guidance as to issues of interpretation. More noticeably, the Commission explicitly excluded from the scope of its conclusions the evolution of rules of customary international law through time. Apart from these areas, the need arises very commonly in practice for the interpretation of rules stemming from acts of international organisations. More generally, are there rules or methods of interpretation with respect to international law beyond treaties? How do they compare to the rule(s) of treaty interpretation and to each other? 

This workshop aims to map out the current trends in the study and regulation of the process of interpretation in international law. To this end, we invite contributions of a conceptual, theoretical, or empirical nature on overarching issues of the international law on interpretation, which include: 

Questions posed at the workshop

A. The Rule of Treaty Interpretation and its Evolution 

– How have the rule(s) of treaty interpretation evolved through time? 

– What is the relationship of the rule of interpretation under the VCLT with the customary international law on interpretation? 

B. Interpretation of International Law beyond Treaties 

– Are there rules of interpretation of international law besides those relating to trea-ties? 

– What are the rules/methods of interpretation of unilateral acts or declarations of states and how do they compare to other rules of interpretation? 

– What are the rules/methods of interpretation of acts of international organisations and how do they compare to other rules of interpretation? 

– Are there rules of interpretation of customary international law or general princi-ples of law? How do these rules compare to other rules of interpretation? 

C. A Normative Approach to Interpretation in International Law: Prospects and Chal-lenges 

– How do rules of interpretation come into existence in international law? 

– How do rules of interpretation in international law evolve over time? 

– Which underlying considerations determine the content of rules of interpretation in international law? 

– Does (or should) international law favour a normative approach to interpretation and why? 

– Does (or should) international law favour a unified or differentiated approach to interpretation (for instance, depending on the special regime in which the rule be-ing interpreted functions) and why?