How is the Nature of Rome Statute Relevant to the Principle of Legality?

What should a court do if thendefinition of an international crime in its constitutive instrument isninconsistent with that under customary international law? Such an interplaynbetween treaty and custom may be approached from different aspects,[1]nwhile I would like to approach the question by framing it in another way: is itna violation of the principle of legality if an international criminal court,nbased on crimes defined in its constitutive instrument, found a defendantnguilty for a conduct which was not criminalized under customary internationalnlaw at the time it was committed? (Hereinafter 『the legality issue』) Thenprinciple of legality has now been firmly established as a human rightsnprinciple, enshrined in many human rights treaties,[2] asnwell as statutes of international criminal courts.[3] Onenaspect of the principle, prohibition of non-retroactivity, requires that no onenshall be found guilty for his or her act or omission which did not constitute ancriminal offence under international law and domestic law at the time it wasncommitted. In this sense, the answer to the legality issues seems to be 『yes』. Thisnessay, however, by examining some scenarios where the legality issue would benraised, argues that the answer to such an issue is not necessarily that straightforward,nespecially for the ICC, and attention is suggested to be given to the nature ofnthe constitutive instruments of respective courts in order to address thisnissue. Noteworthy, this essay does not intend to examine the nature of the RomenStatute in detail as a wonderful job has done by some other scholars,[4]nhere I just would like to demonstrate the complexity of the legality issue andnshows how it is relevant to the nature of constitutive instruments ofninternational courts and tribunals.

Nuremberg and Tokyo Tribunals

A typical scenario where the legalitynissue would be raised could be found in the Nuremberg and Tokyo Tribunal. Theirnconstitutive instruments, especially Art 6 of Nuremberg Charter and Art. 5 ofnTokyo Charter, define crimes against peace as a crime within the jurisdictionnof the tribunals, however it is questionable whether customary internationalnlaw provided for basis of individual criminal responsibility for aggressive warnwhen World War II began.[5]nBoth the majority judgments accepted the Charters to be binding on thentribunals,[6]nwhich implies that the tribunals just need to apply the definition of crimes againstnpeace provided by their Charters regardless of whether aggressive war wasncriminalized under customary international law. A definite answer to thenquestion whether Nuremberg and Tokyo Tribunal violated the principle ofnlegality could not easily be given, as arguably the principle had not become anrule of positive international law until it was later incorporated into variousnhuman rights treaties.[7] However,nthe case would be different today. With the principle of legality becoming anrule of positive international law, now international criminal courts could notneasily run afoul of this principle.[8]nHowever, the approach taken by the Nuremberg and Tokyo tribunal is still veryninspiring in addressing the issue raised at the beginning of the essay.

Other ad hoc tribunals

Can contemporary international courtsnand tribunals adopt the reasoning at Nuremberg and Tokyo, and argue thatnbecause the statutes of the courts have already defined a certain crime, thusnthey need not care about customary international law existing at the time thencrime was committed? The judges of the ICTY, ICTR or SCSL would answer thenquestion in negative, as their statutes are enacted ex post facto and are considered to be jurisdictional in nature.[9] Innorder to comply with the principle of legality, it is claimed by the UNnSecretary General that the ICTY, for example, would only apply customary internationalnlaw existing at the time the crimes concerned were committed.[10] However,nthis is not necessarily the case for the Rome Statute.

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The International Criminal Court

The recent Ntaganda Appeal Judgment[11]nmight be an example demonstrating one of the scenarios where the legality issuenwould be raised at the ICC. The Appeal Judgment adopted a broaderninterpretation of 『rape』 as defined by the Rome Statute but it is considered bynsome scholars to be contrary to the customary definition of war crimes.[12]nThis was not the first time where the ICC adopted such an expansive approach,nas it had previously found Lubanganguilty for war crime of enlisting child soldier that is also considered by manynas not a crime under customary international law.[13]

Assuming that the ICC is right in itsninterpretation of the notions of rape and recruiting child soldier under thenRome Statute, it seems sound for the ICC to disregard customary internationalnlaw based on Art. 21(1)(a) of the Rome Statute which provides for a hierarchynof applicable law. In this sense, the approach taken by Nuremberg and Tokyonmajority judgment revived. Here, the Nuremberg and Tokyo approach - whichnprevailed definition of crimes in constitutive instruments of the courts overncustomary international law – would be adopted again in the ICC, as the court isnallowed to apply the Rome Statute regardless of whether it is consistent withncustomary international law. This approach would be justifiable for the ICC as arguablynby entering into the Rome Statute, the states of which Ntaganda and Lubanga arennationals accepted the definitions of crimes provided by the treaty to bind onntheir nationals and by accepting Art. 21(1)(a), they consented to the rule thatnthe treaty definitions prevail over those under customary international law. Suchnan explanation is also confirmed by Lubangandecision which ruled that

Accordingly, there is no infringement of the principle ofnlegality if the Chamber exercises its power to decide whether Thomas LubanganDyilo ought to be committed for trial on the basis of written (lex scripta) pre-existing criminal normsnapproved by the States Parties to the Rome Statute (lex praevia), defining prohibited conduct and setting out thenrelated sentence (lex certa), whichncannot be interpreted by analogy in malamnpartem (lex stricta).[14]

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However, what if the legality issue isnraised in cases like Al-Bashir, wherenthe situation is brought ex post factonto the court via UNSC referral and different from Lubanga and Ntaganda, thenaccused here is nationals of non-state parties to the Rome Statue? Thennon-state parties did not accept the treaty definitions of international crimesn- which might be inconsistent with the customary ones[15] -nto bind on their nationals and the case for the ICC is different from that ofnthe ad hoc tribunals which could onlynapply customary international law existing at the time the crimes werencommitted. Wouldn』t the ICC violate the principle of legality if it adopted thenNuremberg and Tokyo approach again like what it did in Lubanga?

To address the legality issue, it isnsuggested to boil down the issue as to the nature of provisions definingninternational crimes of the Rome Statute, whether it is jurisdictional ornsubstantive.[16]nMarko Milanovi?, for example,nargued that the nature of Rome Statue is complex, it may either benjurisdictional, or substantive, or both. The implications of nature of RomenStatute would involve whether the defendant could resort to the principle ofnlegality as a defense. To the extent that the Rome Statute is considered asnjurisdictional in nature, the case would be similar to that of ad hoc tribunals and the ICC could onlynapply customary international law or interpret the Rome Statute in line withncustomary international law without running afoul of customary internationalnlaw.[17]nHowever, if the Rome Statute is considered as substantive in nature, as did bynthe ICC in Lubanga, difficultiesnwould arise in situations involving non-state parties referred to the court ex post facto. Marko suggests anninteresting answer to this difficulty. He argued that to the extent that latternunderstanding is adopted, the fact that the ICC might convict nationals ofnnon-state parties for crimes which were not criminalized under customaryninternational law at the time they are committed does not necessarily run afoulnof the principle of legality, as Rome Statute can be considered as a result of statesnexercising their 『universal jurisdiction to prescribe』[18]nthrough a treaty.[19]nHowever, this explanation would raise disputes on the conditions of exercisingnuniversal jurisdiction, which is complex in itself. It begs the question tonwhat extent can a group of states, by establishing a treaty, define a certainnconduct to be a crime beyond the scope of customary international law and tonbind nationals of a third state.

Based on the above analysis, a definitenanswer to the legality issue raised at the beginning could not easily be given.nWhile as suggested by some scholars, a meaningful approach to the issue wouldnbe to examine the nature of certain provisions of the constitutive instrumentsnof each court defining international crimes and modes of liability. It may bensuggested that a substantive reading of the Rome Statute would be preferred,nwhich might also accepted by the ICC as demonstrated in the above excerpt from Lubanga. However, such a reading couldnstill bring about some difficult problems in cases where nationals of non-statenparties are brought before the court under Art. 12(3) or through referral ofnthe UNSC under Art. 13(b) of the Rome Statute, such as the problem with regardnto universal jurisdiction to prescribe, thus further discussion would benneeded.

[1] e.g. Bing Bing Jia, 『The Relations between Treaties andnCustom』 (2010) 9 Chinese Journal ofnInternational Law 81.

[2] e.g. Art. 7 of the European Conventionnon Human Rights and Art. 15 of the International Covenant on Civil and PoliticalnRights; see generally Kenneth S. Gallant, ThenPrinciple of Legality in International and Comparative Criminal Law (CUP,n2009). ?

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[3] e.g. Arts. 22 and 23 of the Rome Statute.

[4] MarkonMilanovi?, Is the Rome Statute Binding on Individuals? (And Why We ShouldnCare) (2011) 9 Journal of International Criminal Justice 25.

[5] The Nuremberg judgment referred to evidence such as 1928 Kellogg-BriandnPact to prove aggressive war was prohibited while none of the evidence itnreferred to mentioned individual responsibility thereof explicitly.

[6] Tokyo Judgment, 48436, in Neil Boister and Robert Cryern(eds), Documents on the Tokyo InternationalnMilitary Tribunal: Charter, Indictment and Judgments (OUP, 2008)n79-80.

[7] B.V. A R?ling and Antonio Cassese, The Tokyo Trialnand Beyond (Polity Press, 1993) 67.

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[8] e.g. Under Art. 21(3) ofnthe Rome Statute, the interpretation of applicable law before the Court 『mustnbe consistent with internationally recognized human rights』 which covers thenprinciple of legality as included in various human right treaties.

[9] Antonio Cassese, International Criminal Law (2nd edn, OUP,n2008) 5; Claus Kre?, 『International Criminal Law』, Max Planck Encyclopedia of Public International Law < International Criminal Law> assessed 21 June 2017.

[10] 『Report of the Secretary-Generalnpursuant to Paragraph 2 of Security Council Resolution 808』 (1993), S/25704, 3nMay 1993, para 34. ?Noteworthy, herenI do not mean that individual judgments at the ad hoc tribunals did not violate the principle of legality, nor donI argue that a judgment that violate the principle could never constitute anvalid precedent.

[11] The Prosecutor v.nBosco Ntaganda (Judgment on the appeal of Mr Ntaganda against the 「Secondndecision on the Defence』s challenge to the jurisdiction of the Court in respectnof Counts 6 and 9」) ICC-01/04-02/06-1962, A Ch (15 June 2017)

[12] Kevin Jon Heller, 『ICC Appeals Chamber Says A War CrimenDoes Not Have to Violate IHL』 (Opinio Juris, 15 June 2017) <ICC Appeals Chamber Says A War Crime Does Not Have to Violate IHL> assessed 21 June 2017.

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[13] e.g. W. Schabas, AnnIntroduction to the International Criminal Court (3rd edn, CUP 2007) 123; Antonio Cassese, International Criminal Law (2nd edn., OUP 2008) 94-95.

[14] The Prosecutor v.nLubanga (Decision on the Confirmation ofnCharges) ICC-01/04-01/06, P T Ch I, (29 January 2007) paras 302-303. ?

[15] Although the Rome Statute was considered by manynpractitioners and scholars as a codification of customary international law,narguably many rules of Rome Statute go beyond customary rules. See e.g. Marko Milanovic, 『Aggression and LegalitynCustom in Kampala』 (2012) 10 Journal ofnInternational Criminal Justice 165; LeenanGrover, 『A Call to Arms: Fundamental Dilemmas Confronting the Interpretation ofnCrimes in the Rome Statute of the International Criminal Court』 (2010) 21 EuropeannJournal of International Law 543; RogernO』Keefe, International Criminal Law (OUPn2015) 119-20.

[16] Milanovic (n 4).

[17] Milanovicn(n 16).

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[18] See explanation of the notion in Roger O』Keefe, 『Universal Jurisdiction: Clarifying the Basic Concept』n(2004) 2 Journal of InternationalnCriminal Justice 735, 736 etc. ?

[19] Milanovic (n 4)n50.