Acts of International Organizations as Extraneous Material for Treaty Interpretation

Abstract

Acts of international organizations often reflect developments in international law. Therefore, they could contribute to the evolutive interpretation of treaty texts if it were not for Article 31 VCLT, which embraces extraneous material for interpretative purposes but strongly focuses on the parties’ acceptance of the material’s interpretive value. The analysis of national and international case law shows that acts of international organizations are very rarely mentioned in the context of treaty interpretation and very little use is made of the opportunity to establish the ordinary meanings of technical treaty terms through such acts. The organizations’ most important interpretive role lies in the self-application of their constituent instruments, and even then, only with respect to so-called ‘household matters’ concerning each organization’s own procedures and competences. In contrast, the functional authority of organizations concerning the interpretation of the ‘constitutional’ rights and obligations of their Member States requires the latter’s broad acceptance. With regard to treaties other than constituent instruments, the analysed case law illustrates that domestic and international courts continue to demonstrate great reluctance in using the acts of international organizations in their interpretive processes and, when they do, they do so in a faltering manner.