I am grateful to EJIL:Talk! for hosting the discussion of my article and chapter. I am privileged to have Anastasios Gourgourinis, Jessica Howley, and Robert Howse as discussants. In the following paragraphs I summarise the main arguments made in the article and the chapter.
The starting point of the argument is that investment law partly borrows and partly diverges from pre-existing regimes of international law. An interpreter of an investment protection treaty is required to determine the degree of similarity and difference so as to elaborate the meaning of particular terms, broader systemic structures, and underlying secondary rules. In order to situate investment protection law within the broader international legal order, an interpreter might draw upon multiple legal techniques from established legal regimes. Within the four corners of international law reasoning, the models of direct rights, beneficiary rights, and agency are the most plausible, relying on techniques drawn from, respectively, the law of human rights, law of treaties on third parties, and diplomatic protection. A firm position regarding the legally most plausible model will not be taken. Instead, the implications of relying on the techniques of those regimes will be spelled out, applying across different branches of international law.
The EJIL article under discussion examines whether and how the invocation of responsibility by a non-state actor has affected secondary rules of state responsibility. The shift from the state to the investor as the entity invoking responsibility for the breach of investment treaties seems to have influenced the law of state responsibility in a number of distinct ways. The apparent disagreement about the law of state responsibility may sometimes properly relate to questions of treaty interpretation, while in other cases rules from an inter-state context are applied verbatim. In yet other cases, the different perspectives lead to importantly different conclusions regarding circumstances precluding wrongfulness, elements of remedies, waiver of rights, and, possibly, interpretative relevance of diplomatic protection rules. The forthcoming chapter applies the same analytical perspective to the law of treaties, examining rules on interpretation and treaty-making through the lenses of other regimes of international law. The overall thesis is that the conceptual perspective of plausibly different readings of the genealogy of foundational structures of investment law is very important, but needs to be applied with subtlety: sometimes all the perspectives point in the same direction; sometimes they do not; sometimes they do but for very different reasons; and, in any event, a diligent application of such traditional techniques of legal reasoning as interpretation, resolution of conflicts, and analogies is just as important for reaching the right legal result.