The Oxford Guide to Treaties Symposium: Starting a Conversation on Interpretation

For the past 15 years courts, tribunals, practicing lawyers and academics concerned with treaty interpretation have been paying increasing attention to the three articles on the topic in the 1969 Vienna Convention on the Law of Treaties. Because the International Law Commission as architect of these provisions confined their drafts to what they saw as general principles, stated laconically and in places elliptically, there has been some scope for dispelling misunderstandings.

Among the points made by the ILC were that the general rule is the whole of article 31 VCLT; that subsequent agreement and subsequent practice are authentic interpretation (the latter showing particularly that the approach is not a purely textual or literal exercise); that ordinary meaning, as part of the general rule, does not indicate some mythical single meaning but typically one selected by reference to context and to object and purpose; that the reference to relevant rules of international law was, at least in part, included to take account of intertemporal considerations; and that consideration of the circumstances of conclusion and of preparatory work was not to be unduly inhibited, the stated limitations applying only to their use as a determining factor.

However, the ILC never saw these provisions as anything amounting to a complete set of formulae for interpretation.  Thus investigation of the subject has moved on to consider, among other things, whether there are particular approaches to be taken in special subject areas such as human rights or international trade, how to deal with time factors, whether particular considerations arise if international organisations are involved, whether there is a useful potential crossover from the  originalist/constructionist debate in constitutional interpretation, and whether an evolutionary method of interpretation forms a distinct approach.

The Guide takes up some of these issues but much of its consideration of the topic is set in the context of the VCLT provisions.  Perhaps now is a good opportunity to take stock of new lines of investigation.