Editor’s Note: This piece is part one of a Symposium on the potential benefits and challenges of a single residual mechanism. You can find the introduction and links to all the posts here.

In December 2022, Karim Khan, the Chief Prosecutor of the International Criminal Court (ICC), stated that the ICC should undertake the prosecution of any crimes arising out of the war in Ukraine within the ICC’s jurisdiction, arguing that “we should avoid fragmentation, and instead work on consolidation.” His statement was issued in reaction to calls from the international community to hold Russia accountable for crimes committed against Ukraine since launching its full-scale invasion in February 2022.

Created at a moment when establishing temporary (ad hoc) or hybrid tribunals was the norm for prosecuting atrocities, the ICC represented a monumental shift: for the first time in history, the international community established a permanent court to prosecute crimes of an international nature, across a variety of States and conflicts. The ICC’s establishing treaty, the Rome Statute, consolidated the international community’s understanding of international criminal law as it existed in the late 1990s. The Rome Statute serves as an important touchpoint today, as the norms of international criminal law continue to expand and evolve. In fact, international criminal law has evolved since the end of WWII by developing or fine-tuning new substantive crimes, as well as by developing new institutions such as the ICC and various ad hoc and hybrid tribunals. 

This symposium proposes a change in the structures of international criminal law that could have similarly profound impacts on the overall field: the consolidation of residual mechanisms for ad hoc and hybrid tribunals – the bodies that carry out the tasks of these tribunals after their prosecutorial mandates have concluded – into a single residual mechanism.

Transitioning from Criminal Tribunals to Residual Mechanisms

Since the end of World War II, the international community has periodically sought to provide some amount of justice, and some sense of closure, to societies impacted by war. This is often done through the establishment of temporary criminal tribunals, which operate either under international law or under a hybrid model that blends international law with the domestic law of the country where the conflict arose. These criminal tribunals are designed to provide prosecutions with the financial and technical resources of the international community, which are often lacking in post-conflict areas, as well as a degree of impartiality through the participation of actors external to the conflict. International tribunals such as the International Criminal Tribunal for the former Yugoslavia (ICTY), the International Criminal Tribunal for Rwanda (ICTR), and hybrid approaches such as the Special Court for Sierra Leone (SCSL), the Extraordinary Chambers in the Courts of Cambodia (ECCC), and the Special Tribunal for Lebanon (STL), have been designed and funded by the United Nations to investigate, charge, and prosecute those most accountable for atrocities committed during the conflict in question.

Because many of the tribunals’ other functions and responsibilities continue past the conclusion of these prosecutions, international and hybrid criminal tribunals transition at some point from full-fledged courts into residual mechanisms. In theory, the transition from tribunal to residual mechanism would occur after all of the prosecutions of individuals indicted by a tribunal are complete. This would allow the residual mechanism, post-transition, to retain staff only for core residual functions such as sentence enforcement, adjudicating contempt of court, continuing victim and witness protection services, and maintaining the tribunal’s archives. The residual mechanism would also likely have some role in promoting the continuing legacy of the tribunal, such as providing education to younger generations about the conflict and memorializing those who suffered.

In reality, however, transitioning a tribunal to its residual phase is far more complicated. Tribunals may transition when all apprehended indictees have been prosecuted but while indicted fugitives are still at large, leaving the new residual mechanism responsible for potential future prosecutions. This was the case with Rwandan suspected genocide finanicer Félicien Kabuga, who was indicted by the ICTR in 1998 and 2003, but not arrested until 2020, some eight years after the ICTR transitioned into residual status within the International Residual Mechanism for Criminal Tribunals (IRMCT)

Political dynamics within the U.N., compounded by the burden of financing these tribunals over long decades, can also drive a tribunal into residual form before its operations are complete. The quintessential example of this problem is Lebanon’s STL, which ran out of funding before apprehending any suspects and prematurely transitioned into its residual stage. 

Such challenges illustrate how the promotion of thorough and comprehensive justice is often at odds with the necessity for such justice to be cost-efficient.

Introducing the Idea of a Single Residual Mechanism

In light of the complexities associated with transitioning each criminal tribunal to a corresponding residual mechanism, it is worth considering the idea of establishing a consolidated single residual mechanism. This entity would be responsible for operating the core residual functions of any international ad hoc or hybrid criminal tribunal whose major prosecutions were completed. 

Consolidating residual functions across tribunals has the potential to better serve the interests of promoting global justice and accountability, and to increase the administrative efficiency of the current, disparate system of residual mechanisms. 

A consolidated residual mechanism could better promote justice by providing a foreseeable residual transition for new tribunals, and by ensuring the protection of continuing core residual functions, regardless of the funding arrangement or political visibility of the tribunal. For example, providing a pre-established home for tribunals at the end of their primary functions could ensure that entities like the STL receive the funding they need to continue any critical residual operations. At the same time, a single residual mechanism’s consolidated staff and resources could increase operational and cost efficiencies, as could the maintenance of consolidated archival systems within a single building. The identification of such monetary, administrative, or other efficiencies inherent in consolidation may encourage States to invest in a permanent single residual mechanism. In fact, States have already expressed support for such consolidation based on the need for efficiency in Security Council Resolution 1966 establishing the IRMCT (for Yugoslavia and Rwanda), which expressly stated that the residual mechanism “should be a small, temporary and efficient structure.”

Beyond its potential administrative benefits, a single residual mechanism might further efficiencies within the larger project of international criminal law by encouraging convergences in procedural rules and in legal interpretation of similarly worded statutes. In fact, tribunals might endeavor to word the procedural rules of their statutes similarly to those of previous tribunals, if they know that most tribunals will eventually be rolled into the same single residual mechanism that has interpreted the wording of those previous statutes.

Moreover, a single residual mechanism could serve as a repository of knowledge and best practices gathered from practitioners within all of the former tribunals. A single residual mechanism would be able to rely on the expertise of former practitioners from different international and hybrid tribunals on unique and complex legal issues, as well as on evidentiary and procedural matters, such as ensuring continuity in maintaining evidence (e.g., replacing witnesses who become unavailable in fugitive indictee proceedings) or correctly interpreting and applying various procedural rules. 

Notably, greater convergence in international norms would not necessarily lead to a decreased emphasis on the regional specificity of each former tribunal’s operations. The IRMCT is the only existing consolidated residual mechanism, hosting the core residual functions of both the ICTY and the ICTR. Yet, the IRMCT acknowledges the differing needs of the populations of the former Yugoslavia and of Rwanda, which it dually serves in matters such as victim and witness protection and educational outreach to the local communities by maintaining regional offices in both The Hague, Netherlands, and Arusha, Tanzania, the locations where the two predecessor tribunals operated. A single residual mechanism thus may be a useful tool to continue to serve the specific needs of individual impacted populations, while allowing lessons learned from working with those communities to inform its future work elsewhere.

Questions and Challenges in Establishing a Single Residual Mechanism

Establishing a single residual mechanism in practice, however, would come with a host of complicated questions and challenges. These include addressing the varied demands of the different tribunals in terms of knowledge of substantive law; determining the scope and mandate of a consolidated mechanism, including whether such a mechanism should hold prosecutorial powers or not; as well as broader concerns such as diminished operational flexibility, reconciling different archival approaches, and the need to take into consideration the various views of victims, indictees, and defendants. These challenges will be explored in greater detail in Post II of this Symposium, but it is worth previewing some of the anticipated complexities upfront.

The strongest precedent for consolidation of international criminal tribunals, the merging of the ICTY and ICTR into the IRMCT, provides some insights into the challenges that a single residual mechanism might face. The IRMCT is an unusual example in that the founding statutes of the ICTY and ICTR were very similar. This made the two tribunals’ consolidation into one residual mechanism relatively simple. The process might not work nearly as well for tribunals with dissimilar founding statutes and less-reconcilable organization and functioning.

Hybrid tribunals, which often mix international law with the law of the affected jurisdiction, also pose a particularly interesting challenge. The ICTY and ICTR both implemented exclusively international law that a common roster of judges could easily navigate. In contrast, the hybrid tribunals, the STL and the SCSL, both used international substantive law and aspects of domestic (Lebanese or Sierra Leonean) criminal procedural law. Any single residual mechanism actively conducting prosecutions for these hybrid tribunals would require judges to become equally well-versed in the relevant international and domestic laws used. Similarly, the ECCC operated through a special hybrid structure with two chambers – one international and one domestic – and applied both international and domestic law, presenting similar concerns within a single residual mechanism structure as the STL or SCSL.

The ICTY and ICTR were also created in an identical fashion – through a U.N. Security Council resolution under the Chapter VII powers of the U.N. Charter – while tribunals such as the SCSL were created through bilateral agreement between the affected country and the U.N. Consolidating the residual mechanisms of any of these tribunals would likely require an amendment to the founding statute of each tribunal. Thus, between the political complexities of passing additional Security Council resolutions and negotiating the domestic legal aspects of the hybrid tribunals, careful consideration should be given to whether any future single residual mechanism should attempt to consolidate all existing and future residual mechanisms, or merely some.

Questions beyond a single residual mechanism’s sources of law arise when determining what specific functions a single residual mechanism should undertake. One major consideration is whether or not any single residual mechanism should hold prosecutorial functions. The underlying tribunals are created for the purpose of carrying out prosecutions, and thus these tribunals ideally would not transfer to a single residual mechanism until after their prosecutions were substantially complete, thereby eliminating concerns over substantive choice-of-law and staffing. In practice, however, transfers may need to occur prior to completion of prosecutions, raising questions over the scope of a consolidated single residual mechanism’s prosecutorial mandate.

Beyond source of law and mandate, additional concerns over the possibility of a consolidated single residual mechanism include diminished flexibility in operations and staffing, greater bureaucratic roadblocks and accessibility to personnel, and less visibility for the work and accomplishments of smaller tribunals. Reconciling different electronic archival systems is also quite a time-intensive and resource-heavy project, and the IRMCT’s continuing regional operations in both The Hague and Arusha have not created many real-estate efficiencies. 

Additionally, both victims and indictees might take issue with consolidation. If lacking in sufficient outreach to and coordination with local communities, a single residual mechanism might be less personalized to the transitional-justice concerns of the victims of any given atrocity, and might place a greater physical distance between them and the mechanism tasked with providing them with justice. In addition, indictees and defense counsel might object to any differing procedural standards between the initial tribunals and any single residual mechanism, as well as any increased difficulty in gaining access to court personnel in a consolidated structure.

Such considerations, among others, reveal possible arguments against consolidating the existing residual mechanisms in the first place. Decisionmakers tasked with designing and operating a single residual mechanism would need to take this full range of concerns into account.

This symposium explores the concept of establishing a single residual mechanism, and identifies both the opportunities for greater efficiency and effectiveness of such a mechanism as well as the possible risks to implementation. As outlined in our introductory post, the discussion is informed by a series of interviews conducted with experts in the field of international criminal law who have worked within various ad hoc and hybrid international tribunals over the past several decades. 

The purpose of this research is not to suggest that a consolidated single residual mechanism is the necessary next step in international criminal justice. Instead, our efforts aim to outline necessary considerations and the possible models a single residual mechanism may take on for maximum effectiveness, if a single residual mechanism were determined to provide net benefits for the international community through the promotion of justice and increased efficiencies. The legal, political, and administrative considerations, as well as possible institutional models for establishing a single residual mechanism, will be discussed in the subsequent two posts.