Interactions between Investment and Non-Investment Obligations in International Investment Law

Abstract

The accelerated proliferation of international investment agreements, the growing number of treaties in other international domains, and the increase of investor-state arbitrations enhance the prospects of overlap between investment and non-investment obligations. The interactions between international-investment and non-investment obligations may be controlled by two main sets of rules: the relatively well-developed principles of public international law or the nascent body of rules emerging from international investment jurisprudence. As analyzed in this paper, investment tribunals have generally not resorted to the relevant principles of public international law. This practical disregard of the regulatory rules of general international law stands in stark contrast to the extensive reliance of investment tribunals on other rules of the Vienna Convention on the Law of Treaties. This current unawareness of investment tribunals may well change in the future with regard to fundamental human rights that are recognized in public international law as jus cogens rules. Contemporary international investment law does not offer a systematic set of rules to be applied to such questions. International investment tribunals that encountered such questions have tended to address these questions in a sporadic manner. Consequently, the paper examines these investment awards separately and seeks to trace some systematic principles that emerge from this jurisprudence. These principles relates to the relevance of non-investment treaties, the different impact of voluntary and non-voluntary obligations, the parties' motivations, chronological sequence of obligations and available information, and least restrictive measures.