International Judicial Monitor
Published by the International Judicial Academy, Washington, D.C., with assistance from the
American Society of International Law

Spring 2016 Issue

Special Report


The Role of Amicus Curiae Submissions at International Criminal Tribunals

Hannah Woolaver
Hannah Woolaver, Senior Lecturer in International Law, Faculty of Law, University of Cape Town, South Africa


Unlike other international institutions, international criminal tribunals use an adjudicative process to determine individual criminal responsibility. Their key actors are not states, but the prosecution and defence. The main way in which other actors (states, international organisations, civil society actors and individuals) can participate directly in proceedings before international criminal tribunals is as an amicus curiae, or friend of the court.

The practice of allowing an amicus curiae to participate in proceedings is included in the rules of procedure and evidence of most international and internationalised criminal tribunals, including the ICC. Practice suggests an increasing reliance on amicus curiae submissions to provide information to the court that may be otherwise unavailable and to advocate certain objectives or views of how international criminal law should develop or be interpreted.

However, over the past two decades a number of challenges concerning the amicus curiae in international criminal tribunals have arisen, reflecting larger issues in the representation, integrity, and fairness of international criminal proceedings. The increasing number of interventions by external actors through the amicus curiae mechanism must be balanced against the already complex nature of the trial process (especially where victims’ participation is also available) and the need to ensure that the fair trial rights of the accused and the principle of equality of arms are not undermined. There has also been an increase in States’ submission of amicus briefs to enable their intervention in international criminal processes, where they do not otherwise have a right to participate. In addition, there has been a growth in ‘non-traditional’ uses of the institution of amicus curiae by parties in international crimes trials, such as the amicus curiae acting as prosecutor during contempt proceedings and as substitute defence counsel.

Each of these developments raises important issues concerning the role of the amicus curiae in international criminal proceedings. These include who is able to participate or be represented in proceedings, why actors seek to directly intervene in trials, whether the amicus curiae is an appropriate avenue for certain types of submissions or for all parties and what obligations and responsibilities such interveners might hold. Here I aim to provide an overview of these pressing issues.

This research stems from an ongoing project on which I am collaborating with Dr Sarah Williams, examining the role of the amicus curiae in international criminal tribunals. We are in the process of collating and analysing all amicus applications and submissions at the major international criminal tribunals. We are also conducting interviews with stakeholders involved in making and using amicus submissions in international crimes trials, including representatives of civil society groups, states, and practitioners. These interviews will be drawn on alongside the analysis of the amicus submissions to assess the role and impact of amicus interventions on international criminal proceedings and the development of the law at these tribunals, as well as to make proposals to guide the use of amicus submissions at international crimes proceedings in the future.

The Amicus Curiae in International Courts and Tribunals

The amicus curiae was traditionally admitted to domestic common law proceedings to act as an impartial adviser to the court. While an advocacy function has increasingly been accepted in amici in some domestic jurisdictions, such as the United States, the traditional role of the amicus was to inform, rather than to advocate. This allowed the representation of interests beyond those of the parties, filling a gap in common law judicial procedure.

Over time, the amicus curiae mechanism also became an accepted part of international judicial proceedings.  Amicus curiae interventions are now permitted before most of the major international courts and tribunals, including the International Court of Justice, the European Court of Human Rights, the Inter-American Court of Human Rights, and the dispute settlement mechanisms of the World Trade Organisation. While the criteria for admission as amici and the rules governing amicus submissions differ from tribunal to tribunal, there is a clear trend of increased admission and reliance on amicus submissions in international courts.[1]

The Ad Hoc and Hybrid International Criminal Tribunals

We can also find provision for the admission of amici in the Rules of Procedure and Evidence in the major international criminal tribunals, including the International Criminal Tribunals for the former Yugoslavia and Rwanda, the Special Court for Sierra Leone, the Extraordinary Chambers in the Courts of Cambodia, and the Special Tribunal for Lebanon. These rules allow for the admission of amici when desirable for the proper determination of the case – a standard that provides for considerable discretion on the part of the tribunal.

Having collated the amicus submissions at the ad hoc and hybrid tribunals, the practice shows a generally welcoming stance to applications for admission as an amicus. Applications for amicus status had a relatively high success rate at these tribunals –approximately 60% of applications for amicus status at the ICTR were successful, as were approximately 70% at the ICTY, 80% at the SCSL and 55% at the ECCC. There were also several instances of different Chambers issuing open invitations for amici. In addition, once admitted, the practice of these tribunals indicates that the amici at times had a significant impact on the proceedings and development of the law. This influence is seen in several key decisions where amicus briefs were heavily relied on and cited, including the decisions of the ICTY Trial Chamber and Appeals Chamber in the Blaskic subpoena decision, and the decision of the SCSL in the Taylor case concerning the validity of immunities before international criminal tribunals. Amicus briefs also had a significant impact on important decisions by the Prosecutor at these tribunals. For instance, the decision of the ICTR Prosecutor to amend charges in the Akayesu case to include charges of sexual violence was a direct result of an amicus curiae brief submitted by the Coalition for Women’s Human Rights in Conflict Situations, leading to the first conviction of rape as an act of genocide in international criminal law. There were also several instances where comparison of amicus briefs with decisions of these tribunals indicated an influence on the content thereof, though the court did not cite these briefs.

The amicus practice at these tribunals allowed for wider participation beyond the parties to the case in the proceedings, including by states and civil society actors. This enabled the representation of interests and perspectives beyond those of the Prosecution and Defence, which can be crucial in mass atrocity trials to properly understand the context, character, and consequences of international crimes.  Nonetheless, the frequent use of amicus submissions and the significant impact of such submissions on key decisions raises concerns relating to the legitimacy and transparency of decision-making, and the impact of external actors at these tribunals. These concerns are compounded by the inconsistent citation of amicus submissions in these decisions, even when we can detect the influence on decision-making through more careful examination.

The Amicus Curiae at the International Criminal Court

The Rules of Procedure and Evidence of the International Criminal Court also provide for the admission of amici. Rule 103 allows the Chambers to ‘invite or grant leave for a State, organisation or person


to submit’ oral or written amicus submissions whenever ‘it considers it desirable for the proper determination of the case’. As with the ad hoc and hybrid tribunals, therefore, the ICC Chambers have a broad discretion to admit amici.

According to the figures that we have compiled for applications made up to early 2016, approximately 85 applications for amicus status have been received by ICC Chambers. We have analysed these applications to determine the actor, subject-matter and alignment of the proposed submissions, as well as whether the applications have been successful. These applications have been made by a variety of actors, including States, intergovernmental organisations, defence representatives from other cases, academics and other individuals, and civil society organisations. The civil society groups are primarily non-governmental organisations, both large international NGOs and small ‘local’ NGOs, but also include professional groups such as defence associations. The proposed submissions deal with a wide range of subject-matter, including submissions on both legal and factual issues, such as: victims’ issues, defence rights, historical background, evidentiary or procedural issues, and contempt proceedings. Thus far, victims’ issues are the most popular topic of proposed amicus submissions. These proposals therefore align most often with the submissions of the victims’ representatives (29% of applications). Perhaps surprisingly, the second-most common alignment is with defence interests (26% of applications), and only a small number of applications received so far clearly align with prosecution interests (4% of applications).[2]

A More Restricted Role for Amici?

Interestingly, the practice at the ICC has, up to this point, been less welcoming to applicants for amicus status than the earlier international criminal tribunals. This is seen, first, as fewer applications for amicus status have been admitted by the Chambers (with a success rate of approximately 35% of applications) and secondly, as the ICC Chambers have made fewer open invitations for amicus submissions on particular topics when compared to the practice of the other tribunals.[3]

While the reasons for this more restrictive stance are not clear, we can speculate as to why this might be. First, the provision for victim participation in the Rome Statute may go some way to explaining this trend. The right for participation of victims in ICC proceedings may lessen the need to rely on amici for the representation of perspectives beyond those of the parties to the case. Also, the equality of arms concerns that existed at previous tribunals are possibly amplified at the ICC due to the provision for victim participation - the defence now must not only counter submissions of the prosecution, but, often, those of victims as well. The additional burden of further submissions from amici curiae, when aligned with the interests of the Prosecution or the victims, may be seen as generally unnecessary for this reason.

There are other reasons that may explain the less frequent use of amicus briefs at the ICC. Since the ICC Chambers have the benefit of more accumulated jurisprudence it may be that additional assistance from amicus submissions is needed less frequently. Also, there may be a greater level of expertise in international criminal law among ICC judges than in earlier tribunals, as judges’ qualifications are regulated by the Rome Statute.[4] This might again have the result that amicus submissions are often unnecessary

An Inconsistent Test for Admission of Amici?

Alongside the low rate of accepting amici at the ICC, the judicial practice that we have examined indicates that criteria for the admission of amici may not be consistently applied. As I mentioned above, the Rule 103 requires only that the Chamber in question ‘considers it desirable for the proper determination of the case’ to grant amicus status, leaving the discretion broadly defined. Without further practice directions or guidelines, the Chambers have used seemingly divergent criteria when assessing amicus applications. Some Chambers have applied a demanding threshold that amicus submissions will be allowed ‘only on an exceptional basis’ or where they would provide ‘an indispensable aid’.   In other cases, amici have been admitted simply because they ‘may assist’ the Court. This suggests that some amicus applications are subject to more stringent tests for admission than others, making it difficult to predict which applications will be successful.

One issue that requires attention is whether the test for admission varies depending on who is applying for amicus status – in particular, whether States and intergovernmental organisations have been given more lenient treatment than civil society organisations when seeking to appear as amici before the ICC. For instance, when the government of Kenya applied for amicus status in the Ruto and Sang proceedings, the Trial Chamber granted the application on the basis that it ‘may be of assistance’ to the Court. Similarly, the Appeals Chamber admitted the African Union Commission as an amicus in the same case without explaining why their application was granted, or indicating whether the submissions would assist the Court. This can be compared to the ‘indispensable aid’ criterion applied by the Trial Chamber to reject the application of a civil society group seeking admission in the Katanga case. [5]

This potentially preferential treatment for state representatives raises questions as to who is able to access and influence the proceedings at the ICC, and whether provisions of the Rome Statute opening participation to external actors are being applied as intended. Given that both the Government of Kenya and the AU Commission clearly had vested interests in the Ruto and Sang proceedings, as the case concerned the Kenyan Deputy President, their admission as amici undermines the supposed impartial nature of the role. In addition, as has been made clear in interviews that we have conducted with representatives of civil society groups, the stringent and unpredictable character of the test for admission of amici at the ICC deters civil society groups from investing the time and resources necessary to compile amicus applications. This creates a barrier to potentially important contributions that such groups can make to the jurisprudence of the Court.  

Further Analysis and Conclusions

We are now set to undertake further analysis on the impact that amicus briefs have had at the ICC. Central to this analysis will be an examination of whether the significant impact of amicus submissions that was observed at the ad hoc and hybrid tribunals has carried over to the ICC, and perhaps even been augmented, given the more discriminating approach to the admission of amici at the ICC. Another factor that we will examine is whether the ICC Chambers are more consistent in their disclosure of such influence, by explicit citation of amicus submissions rather than unattributed ‘borrowing’ from such submissions that was at times observed in the decisions of the earlier tribunals. Furthermore, it will be important to determine whether the preference for States’ applications for amicus status translates to a greater influence in the decision-making of the ICC.[6]

Despite the uncertainties and inconsistencies in the ICC’s practice on amici, it is clear that States, individuals, and civil society organisations continue to consider this to be an important means of interaction with, and potential influence on, the Court’s decision-making. The African Union, for instance, has recently resolved to seek amicus status in all cases involving African leaders, indicating that the AU believes this to be a possible means to shape these cases.[7] As one of the few mechanisms available for external actors to participate in ICC proceedings, it is therefore crucial to understand what role amici have played at the ICC, and how better to regulate this important mechanism. Such understanding should encourage participation by external actors as contemplated by the Statute, while also seeking to ensure the consistency and legitimacy of the Court’s decision-making, and crucially, the fairness of ongoing and future trials for atrocity crimes at the ICC.


[1] See Williams and Woolaver ‘The Role of the Amicus Curiae before International Criminal Tribunals’ 6 International Criminal Law Review (2006) 151

[2] See Williams and Palmer ‘Civil Society and Amicus Curiae Interventions in the International Criminal Law’, in Williams and Woolaver (eds), Acta Juridica (2016) (forthcoming).

[3] See meeting summary of ‘Shaping the Law: Civil Society Influence at International Criminal Courts’, Chatham House and Doughty Street Chambers, available at

[4] See Article 36 Rome Statute.

[5] See Williams and Palmer, supra, for further discussion.

[6] See Williams, ‘Aggression, Affected States, and a Right to Participate’ AJIL Unbound March 2 2016, available at

[7] Decision of the Assembly of the African Union, 25th Ordinary Session, South Africa, 14-15 June 2015.

ASIl & International Judicial AcademyInternational Judicial Monitor
© 2016 – The International Judicial Academy
with assistance from the American Society of International Law.

Editor: James G. Apple.
IJM welcomes comments, suggestions, and submissions.
Please contact the IJM editor at