Reaching Mutual Consensus: ICC, ICJ and the Crime of Aggression

Written by Jan Guardian

International Criminal CourtNone should underestimate the significance of the outcome of the first Review Conference on the Rome Statute of the International Criminal Court (hereinafter ICC),[1] namely, the adoption of a resolution[2] amending the Rome Statute that includes a definition of the crime of aggression[3] and the conditions under which the Court, in the future, could exercise jurisdiction with respect to the crime.[4] Whereas the definition of the crime of aggression is rather clear and was laid down a while ago by the Special Working Group on the Crime of Aggression,[5] and the preconditions for the exercise of the jurisdiction over the crime by the ICC raise minor concerns, if any at all, there are still some ambiguities in respect to the hypothetical possibility of the ICC and the International Court of Justice (hereinafter ICJ) reaching different conclusions in their decisions regarding the unlawful use of force and, thus, establishing either the presence or the absence of an act of aggression.

Given that the ICC is fully seized with the crime of aggression in any particular situation and that by the time the ICC proceeds to a verdict on a prosecution for the crime of aggression the Security Council has likely already made any conflicting decision possible,[6] the ICC judges are authorized to make their own determinations on aggression, since such, made by an organ outside the ICC “shall be without prejudice to the Court’s own findings” under the Rome Statute.[7] Hence, if the case is subject to simultaneous consideration by the ICC and the ICJ, there is ample risk that this will amount to inconsistent decisions.

The classic example of a similar decisional inconsistency between the judicial bodies of the international legal order is that of the ICJ and the International Criminal Tribunal for the former Yugoslavia in Nicaragua[8] and Tadić[9]cases, largely referred to in the legal literature as one of the inconsistencies leading to the fragmentation of international law.[10] The consequence of such an occurrence in the cases brought before the ICJ and the ICC appears to be particularly problematic given the highly-charged political atmosphere in which the ICC has been operating during the years, its fragile credibility and a lack of a proper institutional hierarchy within the international legal system.[11] Yet, the point is not to take a stand in favor of either of the two bodies, but rather to create a functional and logical system that would eliminate any discrepancies at an early stage of the proceedings in the case of aggression, which is deemed to be especially important in the light of the tensions between the states concerned.

A reasonable suggestion would, thus, be for the ICC to request the General Assembly to seek an advisory opinion from the ICJ pursuant to Article 96(a) of the United Nations Charter (hereinafter UN Charter)[12] and Article 65(1) of the ICJ Statute,[13] or to be so authorized by the General Assembly to request such an opinion proprio motu at any time pursuant to Article 96(b) of the UN Charter[14] as to enable the ICC to use the findings of the ICJ and for such a request to be a precondition for the exercise of the jurisdiction by the ICC.

It is worth mentioning, that this option was included in the Discussion Paper proposed by the Coordinator of the Preparatory Commission for the ICC[15] but was somehow dismissed later on. One of the main arguments against this option was that “because the determination of the existence of an act of aggression is a matter that affects the responsibility of a particular State that it is inappropriate as a subject of a request for an advisory opinion.”[16] However, this is quite arguable in the light of the fact that (1) the issue of an advisory opinion does not trigger state responsibility per se, and that (2) the interstate dispute at stake and subsequent determination of state responsibility will only be subject of consideration of the same judicial body that issued the advisory opinion, namely the ICJ, which is well-known for its consistency. Therefore, the request of the advisory opinion of the ICJ by the ICC in cases concerning the crime of aggression seems to be a logical choice, but the question whether, if at all, this scheme will be put into operation remains.


[1]       UN General Assembly, Rome Statute of the International Criminal Court (last amended 2010), 17 July 1998, ISBN No. 92-9227-227-6, available at: [accessed 12 October 2012].

[2]       Rev. Conf. of the Rome Statute, 13th plenary meeting, June 11, 2010, I.C.C. Doc. RC/Res. 6 (advance version) (June 16, 2010)[hereinafter RC/Res. 6].

[3]       Ibid., Annex I, art. 8 bis (1).

[4]       Ibid., Annex I, art. 15 bis, 15 ter.

[5]       David Scheffer, States Parties Approve New Crimes for International Criminal Court. ASIL Insights, Vol. 14, Issue 16, June 22, 2010, p. 5.

[6]       Mark Stein, The Security Council, the International Criminal Court, and the Crime of Aggression: How Exclusive is the Security Council’s Power to Determine Aggression?. IND. INT’L & COMP. L. REV., Vol. 16, Issue 1 (2005), p. 33.

[7]       RC/Res. 6, supra note 2, Annex I, art. 15 bis (9), art. 15 ter (4).

[8]       Case Concerning Military and Paramilitary Activities In and Against Nicaragua (Nicaragua v. United States of America); Merits, International Court of Justice (ICJ), 27 June 1986.

[9]       Prosecutor v. Dusko Tadic (Appeal Judgment), IT-94-1-A, International Criminal Tribunal for the former Yugoslavia (ICTY), 15 July 1999.

[10]     Enzo Cannizzaro, Interconnecting International Jurisdictions: A Contribution from the Genocide Decision of the ICJ. European Journal of Legal Studies, Issue 1 (2007), p. 4.

[11]     International Law Commission, Report of the International Law Commission, 58th session (1 May – 9 June and 3 July – 11 August 2006), 2006, A/CN.4/L.682, para. 51.

[12]     United Nations, Charter of the United Nations, 24 October 1945, 1 UNTS XVI [hereinafter UN Charter], art. 96(a).

[13]     United Nations, Statute of the International Court of Justice, 18 April 1946, art. 65(1).

[14]     UN Charter, supra note 12, art. 96(b).

[15]     Preparatory Commission for the International Criminal Court, Definition of the crime of aggression and conditions for the exercise of jurisdiction: Discussion paper proposed by the Coordinator, 9th session (8-19 April, 1-12 July 2002), 2002, PCNICC/2002/WGCA/RT.1, para. 4.

[16]     Crime of Aggression: Statement by the United States, September 26, 2001.