This chapter examines the law of treaties in the jurisprudence of the ICJ. The author highlights the Court’s position on key selected issues of interpretation: specifically the language of the treaty; time and treaty interpretation; and the role of policy. The chapter also considers issues of systemic integration, hierarchy and concurrence of rules.

The story finally gets to the interpretation and application of legal norms to the facts of the case. This chapter deals with the first interpretive step, called law-ascertainment, where the interpreter identifies the rules that are relevant to the case at hand. Donning the hat of an explorer, the interpreter maps the body of norms precedents in concentric circles – starting with the sources closest to the centre of gravity of their judicial regime and gradually venturing into more peripheral territory. The results of these practices explains the degree of cohesion or fragmentation in international law. As the legal system grows more complex, interpreters no longer have time and resources to master it all, and prove increasingly partial and selective in their legal readings. The emergence of self-contained regimes is largely due to epistemic constraints which, in turn, reflect the social structures of the international judicial community.

Chapter 9 examines security exceptions known to many investment treaties. These clauses are designed to expand the host state's room to adopt certain measures in the pursuit of security interests without having to compensate foreign investors. While seeking to enhance legal security, security exceptions remain ambiguous and controversial in many respects. The chapter conducts a comprehensive study of relevant case law, not only of recent investor-state arbitrations but also of the World Trade Organization’s dispute settlement body. On this basis, it offers guidance on the interpretation of elements common to security exceptions as well as on the level of review to be conducted by investment tribunals. The chapter delineates the limits of state discretion and proposes that international humanitarian law should have an impact on the application of security exceptions in the context of military operations. In evaluating drafting options, the chapter further assesses the merits of including a security exception in investment treaties and makes suggestions as to their wording and function.

Chapter 3 addresses the potential for norm conflict arising from the parallel application of investment treaties and international humanitarian law. It argues that such conflict must be avoided through treaty interpretation. Drawing from their interaction with human rights law, the rules of armed conflict should inform the meaning of investment treaty clauses through ‘systemic integration’. The chapter shows that investment tribunals possess the authority and duty to conduct such a subordinate examination under humanitarian law as part of the interpretive exercise. Although standards of protection may, as a result, be lower than in peacetime, the chapter argues that giving effect to humanitarian rules through investment law ensures the normative appeal of investment treaties. It allows taking into account military concerns and rejects special treatment of foreign investors compared to ‘ordinary’ civilians. At the same time, the chapter highlights, investment treaties give investors a unique opportunity to enforce international rules during armed conflict and secure compensation for unlawful conduct in hostilities.

Chapter 5 commences the book’s analysis of the operation of the most important investment treaty standards in armed conflict. It focuses on so-called war or armed conflict clauses. These provisions, present in many investment agreements, establish state obligations vis-à-vis investors who have suffered losses during armed conflict and other emergencies. Considering recent arbitral practice in the context of the so-called Arab Spring, the chapter gives guidance on how to understand these understudied clauses, their specific elements as well as their systematic function. While ‘basic’ armed conflict clauses establish a duty of non-discrimination in case the host state compensates other investors for losses suffered, ‘extended’ clauses give a standalone right to claim compensation for certain losses. These clauses convey such a right, among others, in case of requisitioning or unnecessary destruction at the hands of the state’s authorities or armed forces. The chapter shows how the general rules of attribution as well as the rules of international humanitarian law should crucially inform the application of these extended armed conflict clauses.

Chapter 6 closely analyses the operation of investment treaty clauses promising full protection and security. The chapter shows how armed conflict affects both dimensions of this standard significantly. It suggests that the duty to not cause unlawful harm to foreign investors and their invesments should be interpreted as a duty to comply with international humanitarian law standards when applied to the conduct of hostilities. This approach, deriving from the interaction of human rights with humanitarian rules, avoids normative inconsistencies. The due diligence obligation to protect foreign investors and their investments from third-party harm, on the other hand, should be understood as inherently sensitive to prevailing conditions. The state’s (constructed) knowledge of threats to foreign investments, its capacities and resources to counteract these threats, and the notion of reasonableness should guide the analysis under the due diligence standard. The latter element introduces a corrective balancing exercise, opening the way to factor in overriding military or humanitarian concerns.

This chapter examines the contribution that domestic courts may have in the development of rules or guidelines for the interpretation of customary international law (CIL). Through an examination of national cases where courts interpret both domestic and international custom, the chapter traces methodologies of interpretation and motivations behind them. The chapter then asks two questions: how can we learn from domestic interpretive practices? and why should we learn from them? In answer to the first question, the chapter argues that domestic courts can contribute to the development of rules for CIL interpretation beyond the role assigned to them in the framework of sources, and also in informal ways. In answer to the second question, the chapter argues that looking to domestic interpretive approaches for custom may help us fill the ‘gap’ currently existing on this issue in international law, that domestic courts offer a wealth of cases from which we can draw, and that by learning from domestic interpretive practices international law can provide domestic judges with various familiar tools for their further engagement with CIL in the future.

This chapter concludes this book by exploring the success, limitations and future global outlook of the pan-European UNECE environmental regime including challenges for future non-UNECE accession, drawing upon an unparalleled seventy years of experience supporting international law on transboundary watercourses and freshwater ecosystems. From the key findings, this book draws a series of overarching and cross-cutting insights into the rising impact and contribution of the UNECE regime to the clarification and development of international law, which also raises outstanding areas for future research. It explores questions of legitimacy as the UNECE regime moves towards its new global role. This research bears in mind the importance of distinguishing policy arguments for signing up to the UNECE regime with legal arguments. The problem arising from a legal perspective is to ask whether it is good legally when international courts or international institutions endorse a regionally specific detailed regime as global law? This analysis demonstrates that the UNECE environmental instruments were never intended to be geographically exclusive and have also already been co-developed by non-UNECE countries for some time. This research supports the UNECE’s endeavour to embrace a global role but cautions that a strong mandate from non-UNECE countries must drive this process.

This chapter provides an understanding of where international law is at (including customary international law, treaty and case law) in terms of its achievements and shortcomings regarding cooperation over environmental protection and use of transboundary freshwater ecosystems. This work provides a basis for critical analysis over the proceeding book chapters, in relation to the value added by the UNECE. The chapter lays the foundations for determining the UNECE regime’s relationship to international water law, international environmental law and general international law. It explores the role of international courts and the international law commission in interpreting outdated water treaties and bringing their standards of environmental protection closer to contemporary scientific understandings and the more progressive multilateral environmental agreements in accordance with the principle of systemic integration. It also explores instances where Courts have arguably has not gone far enough, leaving gaps in understanding. Unlike Courts, pan-regional or basin treaties and their river basin commissions can develop and interpret rules and principles of international water law on a continual and comprehensive basis and provide the institutional framework which supports implementation and compliance with international water law. This hypothesis, on the added value of the UNECE water regime, is tested over the proceeding chapters.

Does judicial interpretation of IIAs produce epistemic ‘authority’? Interpretation can mean both the process of finding out what texts mean and guidance to the concretisation of abstract general norms in individual instances. In the second sense, interpretation is subconsciously used to narrow the freedom of deciders; a range of interpretative tools is used to generate a quasi-formal unity of meaning across IIAs. Systemic integration is the most used and most potent tool. It enjoins us to assume that meanings are identical, but this is baseless: taking into account external rules could just as easily be the basis for a divergence. However, customary law is less certain and precise than assumed. From the perspective of peer-accepted reasoning-before-decision, the interpreter takes meanings, not external rules, into account. Arbitral tribunals in fact interpret IIAs in light not of a customary norm but of other investment tribunals’ understanding of the meaning of other treaty norms. On that perspective, there is no distinction between interpretative tools. Interpretation cannot unify investment law because it does not change the law, only certain brute facts.

Discussion on human rights before the International Tribunal for the Law of the Sea (ITLOS or Tribunal) often refers to its ‘considerations of humanity’ dictum. Yet this is just one way the Tribunal takes into account the interests and rights of individuals affected by law of the sea disputes. This chapter uncovers multiple modes of engagement of ITLOS with human rights – some subtle, some bold – across three types of procedure: prompt release, provisional measures and merits cases. It illustrates how ITLOS has achieved a ‘humanisation’ of the obligation of prompt release through its context- and purpose-based interpretation; likewise, parties increasingly invoke, and ITLOS tacitly relies upon, human rights as a basis for provisional measures. While the Tribunal’s reliance on individual rights in merits decisions remains limited to date, it may consider human rights on the basis of ‘reference provisions’ within UNCLOS, the ‘considerations of humanity’ dictum and the prohibition on abuse of rights. The analysis reveals that ITLOS has paved the way for human rights to be taken into account in law of the sea disputes and that UNCLOS provides a legal framework for it.

This chapter analyses the various impacts international human rights law has on international criminal law. Through a careful analysis of the most emblematic cases of this interplay – from the case law of the ad hoc tribunals for the former Yugoslavia and Rwanda to the International Criminal Court, it shows that judicial application and interpretation of the Statutes of International Criminal Tribunals and Courts in light of human rights law had a systemic effect on international law. In particular, it formal as well as conceptual legal borrowing from IHRL has led to new interpretations of existing international criminal law; imposed procedural and substantive obligations onto the international criminal tribunals and courts; served as a gap-filler; and qualified existing law. In light of the contextual nuances of international criminal justice, the paper argues that many of the cases demonstrating the systemic effect of IHRL on ICL are not coherent applications of the principle of systemic integration.

Much has been written about the relationship of the WTO with human rights. This chapter reexamines the role of human rights in the WTO, focusing on the dispute settlement function of the organisation. It first discribes the dispute settlement mechanism of the WTO and its role in international dispute resolution. Then it sets out the normative framework of the mechanism, pointing out that while WTO dispute settlement does not have jurisdiction over complaints of human rights violations and human rights are often assumed not to be part of its applicable law, except for jus cogens, it can use universal human rights norms in the interpretation of WTO law under the VCLT. An analysis of the practice of WTO dispute settlement shows, however, that references to human rights in substantive matters are extremely rare. This does not imply that the system is blind to the values defended by human rights, however. The system has preferred to take these considerations into account as value-based arguments in the application of WTO law itself. As to procedural law, the WTO imports human rights terminology, even though the mechanism is state to state only.

This introductory chapter by the editor discusses the goals of the book, introduces the questions central to it as well as develops a methodological framework. It relates to existing scholarship on the impact of human rights law upon other branches of international law and on the fragmentation of international law. It outlines the methodology that was applied in working towards this volume by presenting a range of distinctions that provide conceptual tools for detecting and assessing the different ways how international non-human-rights courts may refer to human rights. These include categories of human rights, sources of human rights norms, and three contexts for their application, namely due process rights applied in the proceedings of the court in question, substantive human rights norms as applicable law or basis for subject-matter jurisdiction, and interpretive reliance on human rights through systemic integration. The chapter also relates to the legitimacy of international courts by showing that how international courts relate to human rights norms matters for factors of legitimacy.