This chapter examines the process whereby the concept of jus cogens was introduced into international law during the 1968–69 Vienna Conference on the Law of Treaties. The 1969 Vienna Convention on the Law of Treaties, the conference’s final product, declared that some rules of international law command universal authority, with Article 53 recognizing ‘peremptory norms of general international law’ (without specifying which norms counted as such). Yet the negotiations through which jus cogens entered into the law of treaties were marked by wide-ranging debates about the nature and limits of the treaty-making power, and ultimately about the basic structure and orientation of international law more generally. On the one hand were lawyers and diplomats from socialist and nonaligned states for whom the concept was potentially useful as a means of undercutting the legality of unequal treaties, colonial concession agreements, and other substantively unjust instruments. On the other hand were lawyers and diplomats from industrialized countries who were committed to the traditional principle of pacta sunt servanda—the ‘sanctity of compacts’—and deeply skeptical of any attempt to introduce a normative spectrum in which a select group of rules would have controlling authority over all others.

No international legal judgment has determined the meaning of the environment’s aesthetic value. But many officials interpret words for international law, including those that must negotiate and administer treaties. Chapter 3 looks to such instances of interpretation as it analyses the meaning of ‘aesthetic’ value in accordance with the Vienna Convention on the Law of Treaties. It considers the meaning of ‘aesthetic’ value as an express term of the conventions on world heritage and biodiversity, and as a term informing the interpretation of the Whaling Convention. Applying doctrinal techniques of treaty interpretation, the chapter argues for understandings of aesthetic value theorised among philosophers of environmental aesthetics. However, the practice of treaty bodies suggests interpretations of aesthetic value that are conflated with natural beauty, cultural value and ethical concerns. The chapter observes that orthodox sources for treaty interpretation are written documents and argues that an examination of visual sources should also be entertained. Images, such as photographs, could provide a rich account of the environment’s aesthetic value in international legal practice.

Chapter 2 reviews the international and EU legal frameworks that apply to the international protection of persons fleeing contemporary armed conflicts from a gender perspective. The chapter explores the relationship between international law and armed conflicts, then turns to the interaction between international refugee law, international humanitarian law and international criminal law. The chapter emphasises the role of international human rights law in recognising the context of armed conflicts for the protection of human rights from a gender perspective. It then examines whether the Refugee Convention definition applies to persons fleeing armed conflicts in accordance with the Vienna Convention on the Law of Treaties (VCLT) , but also more broadly whether international refugee law is able to fulfil its purpose of international protection in light of the changing characteristics of contemporary armed conflicts. The central claim of this chapter is that interpreting the Refugee Convention definition to ensure the effective protection of persons fleeing contemporary armed conflicts requires the incorporation of existing knowledge found in conflict and gender literature. This interpretative obligation is then discussed in the context of EU Member States (MS) acting within the EU legal order.

The principles of effectiveness and subsidiarity offer important guidance to the ECtHR. In interpreting the terms and notions of the various Convention provisions and in assessing the interference and justification of interferences, the Court further makes use of a number of other general principles and starting points. This chapter explains the most important of these principles, connecting them with the two main principles of effectiveness and subsidiarity. Attention is paid to the relevance of the rules of interpretation provided by the Vienna Convention on the Law of Treaties and the special nature of the Convention as a ‘law-making treaty’. Subsequently, three principles are discussed that are of importance to the interpretation and determination of scope of the Convention. These are the notion that the ECHR is a ‘living instrument’, which must be interpreted in an evolutive and dynamic manner, the principle that the Convention should be interpreted in line with the underlying values of the Convention (‘meta-teleological interpretation’ in light of the principles of human dignity, personal autonomy, democracy, and pluralism) and the principle of autonomous interpretation.

In many, if not most cases, the ECtHR relies on its own precedents in interpreting the Convention, but some cases may present the Court with new and difficult questions of interpretation. To answer these, the Court relies on a number of specific principles and methods of interpretation. The Court is guided in its work by several core principles, such as effectiveness, evolutive interpretation and autonomous interpretatio, but these are still relatively abstract in nature and they may not suffice to answer a concrete question of interpretation. For that reason, the Court often also relies on the methods of interpretation as described in the provisions of the Vienna Convention on the Law of Treaties, such as textual interpretation, interpretation in light of the travaux préparatoires and internally harmonising interpretation. This chapter discusses the Court’s use of these three methods. In addition to these methods, the Court has opted for a particular refinement of one of the Vienna Convention’s methods, which is consensus or common ground interpretation. This method and the various sources for the Court’s finding of a consensus are also discussed in this chapter.

The Vienna Convention on the Law of Treaties 1969 contains the body of rules governing the law of treaties. Its scope covers treaties between states. The rules largely reflect customary international law. So even where states are not parties to the Convention, its rules will often apply to their treaty relations by virtue of customary international law. Treaties between a state and an international organisation, or between international organisations, are not covered by the 1969 Convention. But international organisations may be party to the separate Vienna Convention of 1986, which adapts the rules of the 1969 Convention to international organisations. If they are not parties to the 1986 Convention, customary international law will apply to their treaty relations. The 1969 Convention does not cover oral agreements, which are in any case extremely rare. The 1969 Convention does not have retrospective effect. The implications of this are discussed.

Traditionally, the choice of an interpretive method and practice is contingent upon the governing law and nature of the agreement under scrutiny. In this respect, international commercial and investment tribunals have significantly contributed to shaping the pivotal role of legal interpretation within the parameters of international adjudication.

It is now undisputed that the internationalization of wide-ranging economic activities and the emergence of State contracts have reshaped the classic distinction between contracts and treaties, and softened the sharp dichotomy between the national and international orders. Despite the straightforwardness of the distinction between contract and treaty in principle, it is also evident that the distinction is not so clear-cut in practice and international arbitral tribunals are often asked to resolve disputes involving these two types of instruments. This practice has rendered it more difficult to separate the issue of interpretation from that of applicable law.

This entry’s point of departure is an analysis of the scope of the rules of interpretation in light of the growing overlap between legal orders, treaties and contracts. Engaging in a comparison of the methods of interpretation in contracts and treaties, the authors then examine the arbitrators’ gap-filling power when facing an ambiguous term or silence. Arbitral tribunals’ use of aids to interpretation and extrinsic evidence or ‘supplementary means’ to interpretation are also discussed.

This chapter turns to the second step of interpretation, namely content-determination. This exercise can be narrated in two ways: first, by reference to the formal rules of interpretation set forth in the VCLT; second, in light of the assumptions, predispositions, and standards of acceptability shared by the judicial community. The juxtaposition of these accounts highlights the interplay between freedom and constraint in international treaty interpretation. What guides the gaze of the interpreter? Where are the boundaries of their discretion? On the one hand, VCLT rules are powerless before the ontological indeterminacy of legal norms, and have therefore little cash value when it comes to derive exact meaning. On the other hand, the patterned practices and background knowledge of the community impose powerful limitations on the interpreter’s discretion.

The general continuity of investment treaties stands in contrast to traditional rules, according to which the outbreak of war abrogated treaties between belligerents. Even today, it remains a common narrative that specialised customary rules exist on the (dis-)continuity of treaties at the outbreak of armed conflict. Chapter 2 critically scrutinises and ultimately rejects this doctrine of the effects of armed conflicts on treaties. While investment treaties also continue to operate under the International Law Commission’s ‘Draft Articles on the Effects of Armed Conflicts on Treaties’, remaining uncertainties as to the state of the law render a comprehensive examination necessary. The chapter argues that the Draft Articles and the doctrine they incorporate suffer from severe shortcomings. The better approach towards the effects of armed conflicts on treaties and more appropriate reading of contemporary international law, the chapter submits, is to discontinue the traditional invocation of specialised customary rules and reorient the debate exclusively toward general treaty law and the Vienna Convention on the Law of Treaties.

Chapter 2 accounts for the selection of case law which forms the basis of the legal analyses of Article 13. The chapter, further, accounts for three building blocks of importance for the analyses. First, how the Court has provided little abstract and principled reasoning concerning the content of Article 13. Second, how the Court's method of interpretation, as such, provides few answers as to how Article 13 could and should be construed and applied. Third, how the wider precedential effect of the Court's judgments may influence how the Court construes and applies Article 13 in individual cases. These building blocks explain, at least partly, why there there has been, and still is, considerable uncertainty concerning the content of the case law and why the Court's law-making potential concerning Article 13 still is large. The chapter, also, briefly explains how legal literature has been used to clarify the content of Article 13 and why a larger comparative analysis has not been performed.

This chapter focuses on the rules set out in the 1969 Vienna Convention on the Law of Treaties (VCLT). The chapter begins with the concept of a treaty, before discussing treatymaking, with a particular focus on the conclusion of treaties, their entry into force, and reservations to treaties. The chapter then delves into how treaties operate -- namely, their scope of application and their interpretation. Finally, this chapter looks at the invalidity, suspension, and termination of treaties.

This chapter focuses on the rules set out in the 1969 Vienna Convention on the Law of Treaties (VCLT). The chapter begins with the concept of a treaty, before discussing treatymaking, with a particular focus on the conclusion of treaties, their entry into force, and reservations to treaties. The chapter then delves into how treaties operate -- namely, their scope of application and their interpretation. Finally, this chapter looks at the invalidity, suspension, and termination of treaties.

International law is central to the interpretation of both of the Brexit-related treaties. The TCA explicitly requires the parties and any dispute settlement body to interpret it according to the rules of interpretation of public international law, notably the 1969 Vienna Convention on the Law of Treaties (VCLT). The WA, and thus the Protocol, by specifying that any of its provisions concerning Union law or concepts must be interpreted in accordance with EU law (including the case law of the CJEU), implies that its many provisions not concerning EU law will need to be interpreted by the default rules of treaty interpretation, namely those of the VCLT. This chapter provides a brief overview of those rules and some of their implications for these two instruments. It focuses on Articles 31 and 32 of the VCLT, which concern the interpretation of treaties.

Chapter 3 explains the interpretative methodology adopted in this book. It shows that the process of interpreting the law of armed conflict, including Article 36, has so far been lacking transparency both in practice and scholarship. It has been largely marked by presenting the outcomes of interpretation rather than explaining how these outcomes were achieved. To ensure that giving meaning to the terms of Article 36 will proceed in a transparent and principled manner, this chapter addresses the shortcomings of Articles 31 and 32 of the Vienna Convention on the Law of Treaties and suggests an interpretative methodology that helps overcome its limitations. The chapter also draws on the ideas of Stanley Fish and his work on interpretative communities. Thus, interpretation is here understood as a process of ascribing a meaning from a suite of possible meanings to convince the relevant interpretative community that a certain interpretation is the most persuasive interpretation to adopt. The interpretative community includes States, courts and tribunals, the International Committee of the Red Cross, non-governmental organisations and legal, military and academic experts. [177 words]

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.