Based on the recognition that the uncertainty concerning the questions of jurisdiction and admissibility of counterclaims has, in the current practice, led to a pessimistic appraisal of the possibility of raising counterclaims as an option that is not readily available to the host state, this chapter seeks to clarify the requirements of jurisdiction and admissibility for filing counterclaims. After arguing that the determinative element for the parties’ consent to counterclaims is the scope of investment disputes given in the relevant IIA, it confirms, through analysis of the IIA dataset, that the content is actually given under the majority of IIAs. It then examines the questions of admissibility, focusing on the requirement of a close connection between the principal claim and the counterclaim, as well as the issue of a parent company’s liability under a counterclaim based on alleged damage caused by its local subsidiary.

Due diligence has increasingly attracted the attention of scholars but it remains an elusive concept. This chapter explains why a study on the dogmatic foundations of due diligence obligations is timely. Thechapter argues that studies addressing the theory of public international law obligations are still scarce. Yet, they are crucial for properly understanding the externalities of obligations and their functioning on the international legal order. Starting with this premise, the chapter asserts that a theoretical study on due diligence obligations serves two main purposes. First, it allows to better clarify the nature, the content and the scope of operation of these obligations, which are traditionally considered difficult to pin down in the abstract. Second, the chapter advances the hypothesis, to be tested in the course of the book, that a dogmatic reconstruction of due diligence obligations also serves normative purposes. The introduction then sets the methodology and scope of the book and explains why the study of due diligence obligations will be limited to obligations of states and will not cover due diligence obligations of international organisations and non-state actors.

The conclusion of the book briefly reappraises the main findings of the previous chapters. It argues that a study of the foundations of due diligence from the dogmatic perspective of obligations serves both a cognitive and a normative function. First, the conclusion argues that the theoretical reconstruction of due diligence undertaken by the book has helped to overcome their elusiveness and to better understand the nature of due diligence obligations and how they are operationalised in practice. Second, the conclusion argues that construing due diligence as an identifier for a certain class of primary rules supplies a normative function, as it allows normative considerations to be made about how state responsibility for the violation of these rules accrues.

Having determined that states may use a variety of other measures to implement human rights, Chapter 4 explores the permissible role of social institutions therein. Given the state-centricity of international law, social institutions fall (unsatisfactorily) into the category of non-state actors (NSAs). The chapter sets out the various roles that NSAs like some social institutions play regarding human rights, before examining any responsibilities or obligations upon them under international law. Chapter 4 concludes that despite the UDHR’s recognition that ‘every organ of society’ has a responsibility for realising human rights, and its reiteration by the UN treaty bodies, there are no concrete international obligations upon NSAs. However, this state-centricity in international law does not prescribe state-centricity in implementation, as NSAs can legally play a role in implementing rights domestically. Chapter 4 explores this possibility for outsourcing/privatisation via the example of NSAs providing healthcare services, and their relationship with the state when doing so.