Part IV Treaty Application, 16 State Succession in Respect of Treaty Relationships

Abstract

This chapter returns to the international frame, asking how treaties apply in cases of disruption to the international legal order — State succession — a topic addressed by the 1978 Vienna Convention on Succession of States in respect of Treaties (VCSST). The present state of affairs relating to treaty succession suggests that only some of the VCSST’s provisions can serve as a reliable guide to the current State of customary international law (e.g. Article 11’s continuation of all boundary regimes, Article 15’s ‘moving treaty boundaries’ rule). Others constitute progressive development of international law (e.g. Article 31 in cases of incorporation; Article 34 in cases of separation). In any case, modern treaty succession distinguishes not only among the different cases of State succession, such as merger or dismemberment, but also among specific categories of treaties that are subject to different rules or principles. It is therefore difficult to identify a generally applicable legal regime of treaty succession.