Post-Termination Responsibility of States?—The Impact of Amendment/Modification, Suspension and Termination of Investment Treaties on (Vested) Rights of Investors

The recent practice of States to amend, suspend or terminate investment treaties has moved questions of potential 'post-termination responsibility' to the forefront of the contemporary legal discourse in international investment law. Although States have often included provisions in their respective treaties to regulate post-termination protection of investments, some aspects of the aftermath of treaty terminations are still unsettled. This article defines and discusses various types of 'post-termination responsibility' by reviewing current practice, doctrine and jurisprudence on the matter. In that vein, it examines terminations, modifications and suspensions that were unlawful and ineffective, or effective but not capable of releasing the State from all treaty obligations either by virtue of survival clauses or separate principles of vested or third-party rights. It then elaborates on denunciations of the ICSID Convention or terminations of BITs and their effects on pending proceedings or the right to initiate proceedings in the future. Moreover, the article discusses whether survival clauses apply solely to unilateral or also to mutual terminations of investment treaties. It will also address the question whether investor rights may continue to be protected as a result of acquired/vested rights or third-party rights. By analysing the most recent jurisprudence and practice of States, as well as more general foundations of general international law, this article aims to contribute to a clarification of these questions.