Navigating the Grand Chamber Trilemma: The Role of the Large Formation at the European Court of Justice and the European Court of Human Rights

Amid increasing caseloads and an expanding number of judges, both the European Court of Justice and the European Court of Human Rights predominantly adjudicate cases through small chambers of three to seven judges. In addition to these chambers, the two courts also use grand chambers – comprising a significantly larger number of judges – perceived to play a pivotal role in shaping the case law of these courts. However, the proper role of grand chambers at both institutions is currently under scrutiny as evidenced by their recent institutional changes and ongoing debates about their reform. These bodies face criticism for their size hindering effective deliberation and for being used too often and in the wrong types of cases. Additionally, some decisions are criticized for compromised justifications due to the need to seek agreement among a higher number of judges. This prompts a fundamental question: What functions do grand chambers serve? This contribution examines and compares the roles of grand chambers at the two European supranational courts. To achieve this, it develops a theoretical framework proposing three fundamental functions that grand chambers can fulfill. First, grand chambers may ensure case law unity by eliminating contradictions in how small chambers interpret and apply the law. Second, grand chambers might provide for representativity, ensuring that individual decisions reflect the majority view of the court rather than the specific composition of the panel. Finally, grand chambers may be also considered special for the quality of their output, by which I mean the degree to which the decisions they produce and the reasons underpinning them persuade the relevant readership. However, the trilemma faced by high courts in utilizing grand chambers is that each function demands a unique design and usage of the grand chamber, making it impossible for the grand chamber to fulfill all three functions simultaneously. Consequently, jurisdictions must make choices about which function to prioritize and which to suppress. The article investigates how the ECJ and the ECtHR grapple with this 'trilemma.' Drawing on interviews with judges and analysis of institutional rules and case law, it shows that the two courts attribute to their grand chambers a different primary function. While the ECJ emphasizes the representative function of the body, to the extent that it erodes the exercise of the other two functions, the ECtHR prioritizes the function of unity and performance even though it comes at the expense of representativity. The article explains the difference, discusses the pros and cons of the respective approaches, and argues that each court could improve the performance of its grand chamber by constructing it coherently around its preferred function. The contribution is two-fold. First, the research maps out several aspects of internal practices of the ECJ and ECtHR which were so far considered as black boxes. Second, by elevating the so-far parochial debates concerning grand chambers to a more theoretically oriented discussion, the contribution fosters a more critical tone to the current debates on the role and usage of grand chambers in Europe and beyond.