The recourse to customary rules by international adjudicators is a valuable tool for the understanding of this source of international law. This chapter examines patterns employed by the WTO’s Appellate Body when referring to customary international law. This forum is of interest due to its limited material jurisdictional, as it can only ascertain violations of WTO law. The chapter thus analyses the means through which the adjudicators identify customary rules, which customary rules they resort to and for which purposes they rely on these ‘extraneous’ sources. Given these jurisdictional limitations, it is also relevant to understand the difference between the use of customary rules for purposes of interpretation and the application of these sources within WTO dispute settlement. The Appellate Body’s reliance on customary international law is limited: it only resorts to codified rules of treaty interpretation and state responsibility. It also does not properly identify rules of international law, but asserts their existence through other authoritative references. Through this methodology, and by only referring to rules on treaty interpretation and state responsibility as customary law, the AB has more leeway in not overstepping the line between application and interpretation of customary international law and by consequence its jurisdictional limitations.

This chapter analyses a large dataset of domestic court decisions relevant to customary international law (CIL). It finds that domestic courts at times engage in CIL interpretation rather than mere ascertainment, even if they largely refrain from using that term. Domestic courts may interpret CIL autonomously, may defer to and validate international courts’ CIL interpretations, or interpret written documents, such as treaties, codifying CIL norms. Such practices bear out that domestic courts may consider some core CIL norms to be relatively stable and amenable to further refinement through interpretation. When interpreting CIL, domestic courts appear to resort mainly to systemic interpretation and interpretation on the basis of subsequent State practice. This reflects earlier findings by Panos Merkouris with respect to CIL interpretation by international courts. Domestic courts deciding cases on the basis of CIL may want to be more explicit regarding whether they engage in de novo CIL norm-identification or rather in the interpretation of pre-existing and stabilised customary norms. In case of interpretation, they may want to improve the methodological quality of their reasoning by pinpointing the canon of construction which they apply, and by relying on sufficient international (including foreign) legal practice.

The chapter deals with the assignment of cases to reporting judges and judicial formations at ECJ. EU lawyers generally consider the ECJ’s system of case assignment to be one of the most problematic features in the court’s decision-making process. They perceive a strong tension with the right to a fair trial. The aim of this chapter is to understand why the court maintains a system that has been under severe attack for a long time. By closely analysing the practice of case assignment between 2003 and 2019, charting assignment profiles of individual judges, the chapter argues that the ECJ’s assignment system is a key mechanism for the court’s institutional success. It has allowed the court to maintain a sense of common purpose, a strong and persistent idea of its mandate as a guardian of the effectiveness and primacy of EU law. The chapter identifies three key functions case assignment performs. First, supporting jurisprudential stability and continuity by creating an elite group of judges who writes the bulk of the most important ECJ decisions. Second, integrating new ECJ judges through gradually assigning them more difficult cases thereby structuring a learning process for becoming a full-fledged ECJ judge. And third, the ECJ’s system of case assignment has helped to maintain what is generally lost in courts of the ECJ’s size: a place where all twenty-seven ECJ judges and eleven Advocates General are informed on all incoming cases, jointly engage in systematizing the ECJ’s case law and framing the court’s agenda.

There is no such thing as a little war for a great Nation.

What has gone wrong with the twentieth century? Why has the Western World, in spite of its great efforts to stand up for liberty, justice and truth, and its desperate yearning for peace and higher standards of living, brought itself to the very brink of universal disaster?

This chapter shows how biographical research can lead us to better understand the legal and political dynamics that prevailed in the court during the 1960s and 1970s. The chapter presents an innovative use of biographies in the sense that they are not a goal in themselves, but a means to create primary sources to study the court's institutional behaviour and its power struggle with national governments. This biographical methodology uncovered that the bench of judges which ‘revolutionized’ European law in the 1960s and 1970s was not as isolated and apolitical as existing literature had portrayed as so far. The judges could rely on a vast political network, which not only helped them in assessing how far they could push the integration process further in their rulings, but which was also useful when it came to persuading national decision-makers of the fact that the court’s rulings were in their interest. The chapter further addresses the challenges raised by the biographical approach and gives an account of the research strategies adopted to unearth empirical material on mostly unknown judges coming from different national, legal and professional backgrounds.

In this chapter the authors discuss their empirical research strategies through which innovative questions relating to the impact of language and multilingualism on the production of jurisprudence by the ECJ can be examined. Focusing specifically on the significance of language for Advocates General (AGs) at the ECJ, the authors examine how semi-structured interviews and corpus linguistics analysis can shine a light on processes within the ECJ that are otherwise invisible: semi-structured interviews are uniquely suited to uncovering otherwise invisible factors that impact the institutional culture of the ECJ; and corpus linguistics analysis can help to investigate whether those invisible factors can in fact be ‘seen’ in the output of that institution – its jurisprudence. The chapter demonstrates step by step how this unique research design can help to develop original objects of inquiry that speak to broader research questions relating to the impact of language on EU law more generally. By focusing specifically on the ‘added value’ of this type of empirical research to the body of work on the ECJ, the authors show how such methods can be used in an interdisciplinary way to gain a nuanced and rich understanding of the many layers that come together to produce EU jurisprudence.