The chapter presents an overview of the procedural arrangements adopted at the international criminal jurisdictions, namely the UN ad hoc tribunals for the former Yugoslavia and Rwanda and the International Criminal Court (ICC), covering the main milestones from the initiation of the investigation to trial phase to appeals against the judgment and sentence and review. Before delving into the trajectories of an criminal case before international criminal courts and tribunals, the chapter highlights the origins of international criminal procedure in the common law (Anglo-American, or ‘adversarial’) and civil law (Continental, or ‘inquisitorial’) approaches, resulting in its legal nature as a hybrid scheme where the balance between the domestic influences varies by tribunal and over time due to reforms pursued by judge-legislators (ICTY and ICTR) or by states and, to a lesser extent, judges (ICC). The chapter reviews the role and functions of the main actors in international criminal proceedings, including repeat or professional players (judges, prosecutors, and defence) and other participants such as victims and witnesses and states and international organisations. It also highlights the normative importance of human rights to international criminal process and the imperative of complying with the principles of public, fair and expeditious proceedings.

The use of tribunal secretaries in international arbitration brings many benefits, but equally requires safeguards. In the absence of comprehensive case law, institutional rules and international guidelines provide a certain amount of guidance. This contribution seeks to identify the pitfalls and the solutions. Importantly, the use of tribunal secretaries varies considerably, depending on personal preferences and regional and cultural patterns. Given that despite some concerns the use of tribunal secretaries is widespread, a constructive discussion on how to regulate the role of tribunal secretary is important. The appointment mechanism and the tribunal secretary’s independence and impartiality, and mandate need to be ensured and clear, as do their tasks and the basis for remuneration. Different institutions provide different guidance, including in relation to the much debated issue whether and if so to what extent, a tribunal secretary may be involved in more substantive tasks, including drafting the award.

This chapter argues there is a “pull” toward cross-fertilization on procedural questions, meaning cross-fertilization between international courts and tribunals may be more likely for procedural issues than in substantive law. It describes cross-fertilization in relation to procedural issues. Procedural cross-fertilization is a process and is not just about borrowing by adjudicators, but involves contributions by a range of actors. Three considerations facilitate procedural cross-fertilization and even make it somewhat likely: the discretion of adjudicators on procedural issues, adjudicators’ duty to decide numerous procedural issues, and sociological considerations concerning the circulation of a small number of personnel across multiple fora. However, two considerations counterbalance adjudicators’ broad discretion. On one hand, control mechanisms operated by states push adjudicators to remain faithful to their mandates, limiting the space for procedural cross-fertilization. On the other hand, procedural cross-fertilization feeds and is fed by an emerging model of international due process that is affecting all areas of international adjudication.

The role of the judge ad hoc at the International Court of Justice (ICJ or Court) has historical origins in the practice of interstate arbitration tribunals in the 18th and 19th centuries. The drafters of the Statute of the Permanent Court of International Justice (PCIJ), after some debate, provided for party-appointed decision-makers when they designed the first permanent judicial body, and the drafters of the Statute of the International Court of Justice retained this feature, essentially unaltered. This phenomenon has generated occasional commentary about why the role of the judge ad hoc exists in the first place, given the importance of the impartiality and independence of the bench. This chapter aims to contribute to this body of scholarship by re-examining the rationales behind the role of the judge ad hoc, in light of empirical data about how often they are appointed, who they are, and what they do while serving on the bench. In transplanting the role of the judge ad hoc from interstate arbitration, the drafters of the PCIJ articulated a range of rationales that have been continuously reiterated over the last century by commentators and ICJ judges. The data, however, provide only limited support for the various rationales that have been articulated, with the result that the vision of the drafters of the PCIJ Statute does not entirely match the reality of today’s judges ad hoc. The data suggest that judges ad hoc appear to act as intermediaries between the Court and their appointing parties, but to a more limited extent than has commonly been thought. The notion that judges ad hoc help to ensure that the parties’ arguments are fully understood by the rest of the bench is, in particular, not entirely persuasive. Furthermore, while it is possible that judges ad hoc contribute to the confidence that disputing parties have in the ICJ as an institution, and thus the Court’s sociological legitimacy, this is yet to be proven on an empirical level (and falls beyond the scope of this chapter). The role of the judge ad hoc may be best understood as a historical anomaly that apparently still holds value for litigating parties, however limited or symbolic this value might be.