Building on Derrida’s celebrated analysis of the term ‘supplement’, this chapter investigates the fundamental ambivalence of supplementary means of treaty interpretation. While the general philosophy of the Vienna Convention interpretive regime rests on the assumption of a hierarchy between the primary means set forth in Article 31 of the Vienna Convention and the supplementary means of Article 32, qualifying certain means as supplementary presumes that the primary interpretive means are somewhat lacking and in need of a complement. The chapter also focuses on the ‘danger’ of such supplement that has been highlighted in practice, namely, that supplementary means themselves need to be interpreted before they can be used in an interpretive inquiry, reinforcing the larger point made in the book that it is impossible to get an unmediated access to any signified. The chapter argues that since supplementary means are not comprehensively listed in the treaty interpretation regime, a virtually endless number of materials can be made relevant in treaty interpretation discourse through the channel of supplementary means.

How does one ascertain the object and purpose of a treaty? Can a treaty have more than one object and purpose? What does giving effect to the object and purpose of a treaty mean in practice? Despite such fundamental uncertainties surrounding them, the ‘object and purpose’ are widely resorted to in the practice of treaty interpretation. This chapter argues that the object and purpose doctrine is coextensive with a large amount of interpretive discretion. The identification of the object and purpose of a treaty a largely indeterminate process, and the assumption that the treaty makers necessarily want the object and purpose of their treaty to be implemented under all circumstances leaves the treaty interpreter with considerable normative power that can hardly be resisted given the very terms of the assumption. The chapter argues that consideration of the finality of a treaty cannot be an exercise in abstract logic, but meet the requirements of practical reason.

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.

The Vienna Convention on the Law of Treaties remains the yardstick for the interpretation of treaties. International tribunals generally base their decisions on Convention rules, although, as different areas of law with their own dispute settlement systems have developed, there are also particular approaches. The Convention rules are contained in Articles 31--33, and the chapter focuses on these. Each element of the general rule of interpretation in Article 31 and the supplementary means of interpretation in Article 32 is analysed, including the role of subsequent agreement or subsequent practice. Further sections summarise other supplementary means of interpretation and look at treaties in more than one language.

Concerns about what is characterised today as dumping are not new.1 Initial responses to dumping are found in the Brussels Sugar Convention of 19022 and Canada’s first national anti-dumping law in 1904.3 Other common law countries soon followed.4 The issue of dumping was discussed both at the League of Nations and during the 1933 World Economic Conference.5 During the 1946 post-war negotiations of the ITO Charter, the United States proposed an anti-dumping provision modelled on its own Anti-Dumping Act of 1921. There was general agreement among the negotiating parties on the need to address anti-dumping in the ITO Charter. Already at that time, the focus was on developing disciplines governing the use of anti-dumping laws instead of prohibiting dumping.

This chapter focuses on treaty committees that share interpretative functions with adjudicative bodies. The author explores whether, and to what extent, joint interpretative commissions/committees are in fact signs of convergence between international investment law and international trade law. The author addresses convergence through the following four dimensions: spatial, temporal, ideological and functional. She concludes that the ideological dimension demonstrates a deeper convergence than can be seen from the space and time perspectives, namely the introduction of a new epistemic community into the field of international investment. Furthermore, the functional dimension shows lasting similarities and differences between the fields. Nevertheless, deeper analysis shows up complexity in reconciling states’ dual role as both respondents and interpreters in pending proceedings, and this is where convergence meets resistance.