Settlement of Conflicts of Successive Treaties: Problems in the Interpretation and Application of Article 30 of the 1969 Vienna Convention on the Law of Treaties

Article 30 of the 1969 VCLT, the most important article in settling conflicts of successive treaties, contains many obscure aspects and problems related to the application. The word ‘successive’ translated into Korean is apt to cause misunderstanding. When we read the Korean text of the article, it should be kept in mind that the word ‘successive’ only means the earlier and later relation in time between different treaties. In Art. 30 of the VCLT, conflict of treaties is expressed as ‘incompatibility’ between an earlier treaty and a later treaty. In this paper, it is suggested that ‘conflict’ includes not only that among prescriptive norms but also that between prescriptive norms and permissive norms. Art. 30 of the 1969 VCLT only applies to the conflicting successive treaties relating to the ‘same subject-matter’. It is a difficult theoretical problem how we can determine the sameness of the subject-matter of two treaties. It may be said that conflict of treaties occurs only when those treaties deal with the same subject-matter. Therefore, this theoretically difficult problem will not cause practical difficulty in the application of the Article. When two successive separate treaties conflict with each other, Art. 30 will be applied. However, when the original treaty and amended treaty conflict with each other, Art. 40 will regulate the problem. Therefore, it is important to discern whether the two conflicting treaties are the original treaty and the amended treaty or not. If a later treaty is agreed upon through amendment procedures, that will be a strong implication that it is an amended treaty rather than a separate new treaty. The last problem concerns the criterion to be used to determine which treaty is earlier or later between two conflicting treaties. As the adoption of the treaty represents the new legislative intention of the parties, the date of adoption will be the most reasonable criterion.