The Enduring but Unwelcome Role of Party Intent in Treaty Interpretation

Abstract

Party “intent” is not one of the tools that the Vienna Convention on the Law of Treaties (VCLT) gives to treaty interpreters. To be sure, party intent is presumably reflected in the “object and purpose” of the treaty, but it is not a separate criterion; in fact, the VCLT implicitly excludes party intent from playing an interpretive role. Yet many decision-makers, counsel, and academics persistently look to party intent for guidance when interpreting treaties. The most favored nation (MFN) debate illustrates why party intent endures as an interpretive touchstone: treaty language, even when analyzed in context and in light of the convention's object and purpose, does not always lead to clear answers. Both Simon Batifort and J. Benton Heath and Stephan Schill, in their different ways, depart from traditional VCLT analysis and hark to party intent as a reason to endorse a modified approach to treaty interpretation. Yet they also illustrate why party intent is an imperfect tool: party intent is too malleable to be a conclusive guide to treaty meaning.