Ця стаття також доступна українською мовою тут.

[Editor’s Note: This article is part of a Just Security series, Prosecuting the Crime of Aggression Against Ukraine. All articles in the series can be found here.]

In Part I of this series, Oona Hathaway explained the imperative of prosecuting the crime of aggression being perpetrated against Ukraine, and the need to do so through an international criminal tribunal established through the United Nations General Assembly. In Part II, Astrid Reisinger Coracini examined some features of the proposed tribunal, including its jurisdiction and composition. This post continues in that same vein and addresses: rules of procedure and evidence; how many individuals to prosecute; rights of the accused; the judgment; double jeopardy (non bis in idem); amnesty; immunity; and penalties.

The approach draws on the wealth of past experience that exists in forming international and hybrid tribunals, recognizing the possibility of “mixing and matching” elements from various tribunal statutes, to create the best, most legitimate process, and one fully consistent with internationally recognized fair trial standards. The Yale Club presenters were also mindful of creating a streamlined and efficient process, thereby reducing tribunal costs. As previously explained in Part II, the Special Tribunal for the Crime of Aggression (STCoA) is intended to complement the work of the International Criminal Court (ICC), filling in a jurisdictional gap that exists over the crime of aggression, with the ICC playing the crucially important role of investigating and prosecuting war crimes, crimes against humanity, and, as warranted, the crime of genocide committed in Ukraine.

Features of the Tribunal (continued)

1. Rules of Procedure and Evidence

The rules of procedure and evidence of international and hybrid criminal tribunals are often determined by the tribunal’s judges. This was the case, for example, with the International Criminal Tribunal for the former Yugoslavia (ICTY Statute, Art. 15), International Criminal Tribunal for Rwanda (ICTR Statute, Art. 14), the Special Court for Sierra Leone (SLSC Statute, Art. 14) and the Extraordinary Chambers in the Courts of Cambodia (Internal Rules). The States Parties to the ICC’s Rome Statute negotiated its Rules of Procedure and Evidence (Rome Statute, Art. 51.1). For the STCoA, it would seem appropriate for the judges to determine the rules of procedure and evidence as there will not be “States Parties” given that an agreement between the U.N. and Ukraine would establish the tribunal. In order to expedite the work of the judges, they could initially use the rules of one of the existing tribunals; the SLSC took this approach, when it used the ICTR’s rules to start, subject to amendment by the judges (SLSC Statute, Art. 14.)

2. How Many to Prosecute

Participants at the Yale Club meeting repeatedly emphasized that, while the presenters envision the creation of an international tribunal, it would resemble the SLSC, rather than the ICTY or ICTR, in size. 

The SLSC’s Statute only granted power for the SLSC “to prosecute persons who bear the greatest responsibility” for the crimes committed in Sierra Leone (Art. 1.1, SLSC Statute). This focused mandate reflected a reaction by States to the size and cost of the ICTY and ICTR. The SLSC eventually indicted 13 individuals, 10 were brought to trial, and 9 were convicted and sentenced. (See Residual Special Court, Special Court Trials).

While the STCoA prosecutor would need to determine the precise number of individuals to charge, a reference in the statute to those bearing the “greatest responsibility” would be unnecessary, as there is already an in-built numerical limitation within the definition of the crime. Article 8bis of the ICC’s Rome Statute has what is referred to as the “leadership clause.” As Part I of this series explained, the crime is committed only “by a person in a position effectively to exercise control over or to direct the political or military action of a State.” That limits the number of individuals who could be prosecuted to certain high-level political or military leaders. Limiting the number of investigations and prosecutions would be a way to streamline the work of the STCoA and reduce the cost of the tribunal.

3. Rights of the Accused

International and hybrid tribunal statutes enumerate the fair trial rights (due process protections) that must be provided to the accused. For example, one finds these in Article 21 of the ICTY Statute; Article 20 of the ICTR Statute; Article 17 of the SLSC Statute; Article 13 of the Agreement between the U.N. and the Royal Government of Cambodia; and Articles 55, 66, and 67 of the Rome Statute. A few include: the right to a fair and public hearing; the right to be presumed innocent until proven guilty; the right to be informed promptly and in detail in a language which the accused understands of the nature of the charges; the right to adequate time and facilities for the preparation of the defense; the right to be tried without undue delay; the right to examine, or have examined, witnesses against the accused; and the right not to be compelled to testify against oneself. The statute of the STCoA would need to contain such fair trial rights and due process protections. To be credible, and to create deterrence against future violations of Article 2(4) of the U.N. Charter, any trials by the STCoA must fully satisfy these standards.

4. The Judgement

International and hybrid tribunal statutes generally require a reasoned opinion, rendered in writing, in public, by a majority of judges of the trial or appeals chamber, with the possibility of separate and dissenting opinions. (See, e.g., ICTY Statute, Art. 23; ICTR Statute, Art. 22; SLSC Statute, Art. 18; see also Rome Statute, Art. 76). The STCoA statute should follow that approach.

5. Double Jeopardy (Non bis in idem)

International and hybrid tribunal statutes generally provide that the accused may not be prosecuted twice for the same acts or conduct. (See, e.g., ICTY Statute, Art. 10; ICTR Statute, Art. 9; SLSC Statute, Art. 9; and Rome Statute, Art. 20.) An exception applies where the acts at issue in a trial before a national court were characterized as an ordinary crime, or where the national court proceedings were not conducted impartially or independently, were designed to shield the accused from international criminal responsibility, or the case was not diligently prosecuted. (Id.) The STCoA statute should follow the same approach. 

As to who should prosecute first in the event that the ICC and STCoA seek to try the same accused and the person is in custody – a conflict that may not in fact arise – the two tribunals could work that out among themselves, through, for instance, a memorandum of understanding. In any case, it would not be a topic covered in an agreement between the U.N. and Ukraine.

6. Amnesty

The STCoA’s statute could provide that any purported grant of amnesty would not be a bar to prosecution. Similar language, that could be easily replicated, is found in Article 10 of the SLSC Statute. It states: “An amnesty granted to any person falling within the jurisdiction of the [court] in respect of the crimes referred to in . . . the present Statute shall not be a bar to prosecution.” This would be the situation in any event. See Decision on Challenge to Jurisdiction: Lomé Amnesty, Prosecutor v. Kallon, March 13, 2004, at para. 88 (noting that “whatever effect” an amnesty might have had in national courts it was “ineffective” to deprive an international court of jurisdiction).

7. Immunity

The STCoA’s statute should provide that official capacity or immunity would not preclude prosecution. For example, it could replicate language found in Article 27 of the Rome Statute, which states: 

  1. This Statute shall apply equally to all persons without any distinction based on official capacity. In particular, official capacity as a Head of State or Government, a member of a Government or parliament, an elected representative or a government official shall in no case exempt a person from criminal responsibility under this Statute, nor shall it, in and of itself, constitute a ground for reduction of sentence. 
  2. Immunities or special procedural rules which may attach to the official capacity of a person, whether under national or international law, shall not bar the Court from exercising its jurisdiction over such a person.

See also Charter of the International Military Tribunal (“London Agreement”), Art. 7 (“The official position of defendants, whether as Heads of State or responsible officials in Government Departments, shall not be considered as freeing them from responsibility or mitigating punishment.”); ICTY Statute, Art. 7.2; ICTR Statute, Art. 6.2; SLSC Statute, Art. 6.2.

As also discussed in Part I, it is one of the distinct advantages of an international tribunal that any immunity that could attach at the national level (i.e. personal immunities of heads of state, heads of government, or foreign ministers (see Case Concerning the Arrest Warrant of 11 April 2002 (DRC v. Belgium)) would not do so at the international level. See, e.g., Decision on Immunity from Jurisdiction, Prosecutor v. Taylor, May 31, 2004 (Charles Taylor not immune from prosecution before the SLSC, even though indicted while a sitting head of state); Judgment in the Jordan Referral re Al-Bashir Appeal, ICC Appeals Chamber, May 6, 2019 (“there was no Head of State immunity that would have prevented Jordan from executing the [ICC] warrant for the arrest and surrender” of then-President al-Bashir of Sudan). For more on immunity, see Claus Kreß’s Occasional Paper on ICC Appeals Chamber’s Judgment of 6 May 2019 in the Jordan Referral re Al-Bashir Appeal and Commentary on personal immunity (beginning on page 2626); see also Leila Sadat.

Because the crime of aggression is a “leadership crime” – at least under the ICC’s Article 8bis definition – it is imperative that immunity not attach or the very leaders one would seek to prosecute could have immunity. Because immunity may well preclude prosecution before regional, Ukrainian, or other national courts, the absence of such immunity is one of the critical reasons for establishing an international tribunal. We know a tribunal established by way of a treaty between the country concerned and the United Nations, such as the SLSC escaped immunities difficulties; as to whether a tribunal with some degree of “hybridity” established regionally or nationally would do so remains uncertain.

8. Penalties

It is standard for U.N.-established tribunals to limit penalties to imprisonment, thereby excluding application of the death penalty. Consideration of aggravating and mitigating factors is provided for, and asset or property forfeiture can be included. (See, e.g., ICTY Statute, Art. 24; ICTR Statute, Art. 23; SLSC Statute, Art. 19; Agreement between the U.N. and Cambodia, Art. 10; Rome Statute, Art. 77).

Exclusion of consideration of, or citation to, the statutes of other hybrid tribunal statutes is not meant to suggest that they utilize divergent approaches or are not worthy models for consideration.


The above proposals suggest an approach to these topics that could be used as a basis for negotiations between the U.N. and the Government of Ukraine; ultimately, they would need to agree on the final statutory language. As to the topics discussed above, there is fairly “boilerplate” language from past tribunal statutes that could be used to expedite negotiations.  

Above all, it bears repeating, that what is envisioned is a relatively small tribunal, prosecuting a limited number of individuals, with the tribunal serving as a filler for a jurisdictional gap that exists over the crime of aggression in the Rome Statute.

It is worth noting that David M. Crane, Ambassador (ret.) Hans Corell, and The Hon. Irwin Cotler, writing for the Ukrainian Task Force of the Global Accountability Network, have also issued a proposed tribunal statute, and are clearly thinking along the same lines as the Yale Club presenters. Their proposal is modeled on replicating the SCSL’s Statute. While there exist some divergences between our approaches, overall there are more similarities than differences. Both agree on the need for the tribunal, the need to create it through the U.N. General Assembly based on an agreement between the U.N. and the Government of Ukraine, the focus on only prosecuting the crime of aggression, the need to use the definition in Rome Statute Article 8bis, and that a fairly limited number would be indicted and prosecuted. (See also Chautauqua Principles, August 2022, calling for creation of an “international tribunal with appropriate jurisdiction to prosecute those bearing the greatest responsibility for the crime[] of aggression against the people of Ukraine”).

IMAGE: Ukrainian President Volodymyr Zelenskyy remotely addresses the 77th session of the United Nations General Assembly in New York City on Sept. 21, 2022. (Photo by Angela Weiss/AFP via Getty Images)