Contemporaneity and Evolutive Interpretation under the Vienna Convention on the Law of Treaties

Abstract

A line of recent cases in investor–State arbitration have purported to rely on the so-called ‘principle of contemporaneity’ to interpret bilateral investment treaties (BITs). In this context, contemporaneity may be understood as the interpretation of treaty terms in accordance with the meaning they bore as a matter of formal definition or common linguistic usage at the time the treaty was concluded. The purpose of this article is twofold: first, to dispel the confusion created by the conflation of contemporaneity with other temporal issues of treaty interpretation and so-called ‘inter-temporal law’ and, second, to explore the manner in which contemporaneity, as defined above, fits within the well-established principles of treaty interpretation, as reflected in the Vienna Convention on the Law of Treaties (VCLT).2 The article proceeds in five sections. The first section begins with a brief overview of the modern origins of contemporaneity, which can be traced to the work of prominent international lawyer and legal scholar Sir Gerald Fitzmaurice in the late 1950s. The second and third sections separate the different concepts that have been conflated with contemporaneity and explore contemporaneity’s polar opposite, treaty interpretation based on the evolving meaning of treaty terms. The fourth section discusses the recent adoption of contemporaneity and the evolving meaning approach by investment treaty tribunals. The final section considers, in light of the preceding discussion, the proper position of contemporaneity within the framework of the VCLT.