Comments on the Identification of and Evidence Supporting Subsequent Practice Establishing an Agreement of States or International Organizations as to the Interpretation of a Treaty

Abstract

This contribution focuses on the analysis of Articles 31 and 32 of the 23 May 1969 Vienna Convention on the Law of Treaties (VCLT) in relation to means of interpretation. According to the author, article 31 § 3 provides for two types of agreements, respectively under subparagraphs a)and b). This reflection concerns itself with the agreement resulting from subsequent practice within the meaning of Article 31§3, b). The distinction between what comes under Article 31 § 3, b) and that under Article 32 does not appear to have been well received by the International Law Commission (ILC) in its work on the subject titled “Agreements and Subsequent Practice in the Context of Treaty Interpretation”, set out in Conclusion 6 Paragraph 1. The criteria for identifying the existence of a subsequent practice so as to establish an agreement on the interpretation of a treaty emerge from the case law. Evidence of acceptance of a subsequent practice also establishes an agreement on the interpretation of a treaty. If there is strictness regarding State practice, there is more flexibility in the establishment of an agreement on the interpretation of a treaty resulting from the subsequent practice of international organizations. According to his analysis, the author concludes that the loose interpretation of the concept of agreement adopted by the Special Rapporteur - and followed so far by the Commission - which considers that “agreement” in international law does not necessarily lead to a binding commitment, is not convincing.