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s.I Actors, Ch.5 Teachings of Publicists and the Reinvention of the Sources Doctrine in International Criminal Law

Neha Jain

From: The Oxford Handbook of International Criminal Law

Edited By: Kevin Heller, Frédéric Mégret, Sarah Nouwen, Jens Ohlin, Darryl Robinson

From: Oxford Public International Law (http://opil.ouplaw.com). (c) Oxford University Press, 2021. All Rights Reserved.date: 28 November 2021

International criminal law — Sources of international law

(p. 106) Chapter 5  Teachings of Publicists and the Reinvention of the Sources Doctrine in International Criminal Law

I.  Introduction

Does the international criminal law regime subscribe to the same doctrine of sources as classical public international law? On first blush, it is difficult to contemplate any answer that would not be in the affirmative. International criminal law, after all, is one amongst the many (fragmented) branches of international law and can be expected to recognize the same legal sources as authoritative.2 This response is, however, complicated to a considerable degree by at least three factors: the hybrid identity of international (p. 107) criminal law that sits betwixt criminal law, public international law, and human rights law;3 the disputed nature of the sources doctrine in public international law; and the disproportionate role played by international criminal courts in the development of the sources doctrine, especially when compared to other international tribunals.4

This chapter analyzes one of the most controversial areas in the jurisprudence of the International Criminal Court (ICC)—modes of liability—to conduct a broader investigation into whether the classical doctrine of sources in public international law represents faithfully the manner in which sources of law are being conceived and applied in the realm of international criminal law. It does so by focusing on a source of law that has attracted almost no comment in the renewed debate on sources of public international law and has similarly evaded the attention of most international criminal law scholars: the teachings of publicists.5 While the literature on sources in international criminal law has examined discrete sources such as customary international law6 and the decisions of municipal courts,7 this enquiry has mostly been conducted in a piecemeal fashion, rather than through the lens of debates on the sources doctrine in classical public international law.8 The normative and descriptive validity of the sources of public international law and their applicability to international criminal law has been assumed, a phenomenon that is all the more unexpected given that the Rome Statute of the International Criminal Court (ICC) explicitly recognizes a different hierarchy of sources.9

(p. 108) This chapter interrogates the ICC’s use of the teachings of publicists in fashioning novel forms of individual criminal responsibility to argue that the Court, similar to its predecessors such as the International Criminal Tribunals for Rwanda and the Former Yugoslavia, has been quietly engaged in reinventing the classical doctrine of sources and repurposing it to suit the international criminal law regime. The rehabilitation of this largely unutilized source of law has not, however, been carried out in a particularly conscious or informed fashion, at least none that is explicit in the jurisprudence of the ICC. The absence of any doctrinal discussion or even framework is not surprising in light of the Court’s general reluctance to make grand theoretical pronouncements, especially those that raise fundamental issues concerning the identity and goals of international criminal justice.

The chapter unpacks the Court’s innovative approach to the teachings of publicists in the context of forms of criminal responsibility and signals the normative and policy issues that this raises, not only for the international criminal law regime, but also for the sources doctrine in public international law. Part II gives a brief overview of the opinion of publicists as a source of classical public international law. Part III focuses on the jurisprudence of the ICC on modes of liability to highlight the manner in which teachings of publicists have assumed an influence all out of proportion to their traditional role in the development of public international law. Part IV analyses the implications of this use of scholarship and what it reveals about the nature of the international criminal law regime, drawing on domestic law comparisons with the status and position of scholars as sources of legal authority. The chapter concludes by gesturing towards the contribution that a renewed focus on sources of law as applied by international criminal tribunals could make to contemporary debates on the sources doctrine in public international law.

II.  Publicists in Public International Law

While the Statute of the International Court of Justice (ICJ) technically only specifies the sources of law that are to be applied by the ICJ, Article 38(1) of the statute dealing with sources is widely regarded as a template for the sources of public international law more generally.10 Under the statute, the ICJ is entitled to apply ‘judicial decisions and the teachings of the most highly qualified publicists of the various nations, as subsidiary means (p. 109) for the determination of rules of law’.11 This formulation obscures the various tensions underlying heated debates on the appropriate sources of international law during the drafting stage of the precursor to Article 38(1) in the Statute of the Permanent Court of International Justice (PCIJ).

A.  Publicists and Gap-Filling in International Law

Baron Descamps, the President of the Advisory Committee of Jurists in charge of crafting the statute, initially proposed a list that specified, in order of preference, the following sources: (1) conventional international law; (2) international custom; (3) ‘the rules of international law as recognised by the legal conscience of civilised nations’; and (4) ‘international jurisprudence as a means for the application and development of law’.12 Doctrine, or the ‘concurrent teachings of juriconsults of authority’, was introduced as a means of determining the third source, which in turn was an attempt to avoid a situation of non-liquet.13 In a subsequent draft, doctrine appeared in a different guise proposed by Mr Root in collaboration with Lord Phillimore: the Court was now to consider ‘the authority of judicial decisions and the opinions of writers as a means for the application and development of law’.14

This proposal precipitated a lively discussion,15 with some members of the Advisory Committee such as M. Ricci-Busatti expressing dismay and amazement at the idea that doctrine by itself could constitute a source of law.16 To this charge, Lord Phillimore replied that it might be possible for a legal system to accept a rule based solely upon the doctrine of authors, though he later qualified his statement by considering agreement among authors as evidence of custom.17 Professor de Lapradelle, who was unhappy at the prospect of doctrine constituting a source of law, would have narrowed its application to the ‘coinciding doctrines of qualified authors in the countries concerned in the case’.18 Baron Descamps sought to allay these fears by clarifying his position that while doctrine (and jurisprudence) could not create law, they were helpful tools for the (p. 110) judge to determine its existence.19 A tentative compromise was reached in the final wording of the draft that stated that ‘[t]he Court shall take into consideration judicial decisions and the teachings of the most highly qualified publicists of the various nations as a subsidiary means for the determination of rules of law’.20 The ambiguous formulation of the final text, however, fails to resolve the disagreements voiced during the debates on the precise status of the opinion of publicists as a source of international law.21

B.  Publicists as a Subsidiary Source of Law

Subsequent commentary on the teachings of publicists as a legal source has been far from enthusiastic, bespeaking an intriguing modesty of the scholarly community as to their own reliability and authoritativeness. Thus, scholars have largely attempted to highlight the ‘subsidiary’ nature of the teachings of publicists in various ways.22 A distinction has been made between the other three sources—treaties, custom, and general principles—that are considered ‘formal’ or sources of law proper, and judicial decisions and publicists as ‘documentary’ sources that merely evidence the existence of the formal sources.23 Alternatively, emphasis has been put on the nature of the institution that gives rise to the law, such that ‘law-creating’ agencies such as states enact formal sources like treaties, whereas ‘law-determining’ ones like courts and scholars simply elucidate where the law may be found and its content.24

Skepticism has also been expressed at the equal status accorded in Article 38(1)(d) to judicial decisions and publicists.25 For instance, according to Fitzmaurice, ‘[a] decision is a fact: an opinion, however cogent, remains an opinion’.26 While a judicial decision may not be materially any better or more persuasive than a scholarly opinion, it has a qualitatively different impact on subsequent legal proceedings that is plain in the manner in (p. 111) which it influences the attitudes of the parties in framing their arguments and in the extent to which judges feel obligated to follow or distinguish judicial precedents.27 This attempt to privilege judicial decisions vis-à-vis scholarship as sources of law has, however, been criticized for its unconscious perpetuation of a common law bias that ignores the status of scholarly and judicial pronouncements in the civilian tradition whereby both are considered equally accurate (or not) representations of the law.28

Judgments of major international courts such as the PCIJ and ICJ rarely cite doctrine in support of their decisions, leading to speculation on whether doctrine truly has such little value in the eyes of the courts, or if it is read and considered, and merely not cited.29 Indeed, individual opinions often contain citations to scholarship to craft a persuasive argument.30 This has not, however, prevented critics from referencing the low value of the work of international law scholars found in harsh pronouncements by courts such as the English Admiralty Court: ‘A pedantic man in his closet dictates the law of nations; everybody quotes, and nobody minds him … and who shall decide, when doctors disagree?’31 The reluctance to refer to scholarship has been attributed to the highly political nature of the international legal system and to the small and incestuous community of international law scholars, where personal and political rivalries may undermine the strength of the judge’s reasoning if it demonstrated the clear influence of the opinion of one or the other scholar.32 International law scholarship has also been derided as nationally biased, superficial, and prone to making assertions about principles and rules that are unsupported by actual evidence, such as the inattentiveness to state practice in establishing the existence of custom.33

(p. 112) Some scholars have nonetheless alluded to the practice and social reality of the normative authority exercised by international law scholars.34 At least in the beginning of the consolidation and development of international law, the lack of significant judicial practice meant that scholars were often in the vanguard of systematizing and clarifying the content of international legal rules.35 Scholars claim that ‘the books and the opinions of the nineteenth century seem often to resemble catalogues of the praises of famous men. “Hear also what Hall sayeth. Hear the comfortable words of Oppenheim” is an incantation which persists even into this century’.36 Even today, familiarity with the teachings of eminent international law scholars is considered the hallmark of a persuasive legal argument.37 Scholars have also had a deep impact on specialized areas of the law such as the law of diplomatic protection and the law of state succession.38

Additionally, scholars who participate in various governmental and inter-governmental capacities can have an outsize influence on the doctrine.39 This is especially true of academics who go on to illustrious careers as judges of international adjudicative bodies (where their judicial opinions may be an extension of their scholarly work and commitments) and those who are appointed to specialized bodies such as the Sixth Committee of the United Nations or the International Law Commission (ILC).40 Not only do academics constitute a significant proportion of the members of the ILC, but the ILC also frequently relies on well-known publicists in exercising their mandate to codify and progressively develop the rules of international law.41 In this process, the ILC has produced draft articles and prepared the ground for codification conventions that have had a significant influence on states as well as international institutions.42

There is, however, an intriguing discrepancy in the rate at which international tribunals, including the ICJ, cite the work and deliberations of the ILC when compared to (p. 113) other ‘academic’ sources.43 The ILC, in this sense, occupies a fairly unique institutional position, not only because of its status as an organ of the UN and the quality of the texts it produces, but also because the ‘provisions it formulates reflect a synthesis of scholarly opinion tempered by the general trends emerging from the opinions voiced by States’.44 In more recent years, the ICJ has relied directly on ILC draft articles in cases such as the Gabčíkovo-Nagymaros judgment.45 In this case, the ICJ declared that Article 33 of the ILC’s Draft Articles on State Responsibility on the state of necessity as precluding the wrongfulness of an act was reflective of customary international law. It went on to rely on the criteria provided in Article 33 for evaluating the existence of the necessity justification to determine Hungary’s international responsibility.46 The ICJ has since directly referenced the Draft Articles on State Responsibility in numerous judgments, as have other international adjudicative bodies.47

III.  Publicists at the International Criminal Court

A.  Application and Hierarchy of Sources in ICL

Given the extensive discussion on sources of law during the drafting of the Statutes of the PCIJ and ICJ and the subsequent wide ranging academic commentary on sources of public international law, it is surprising to see the scant attention paid to sources in the early stages of the development of international criminal law. The issue of sources was largely neglected during the drafting of the constitutive instruments of the ad hoc international tribunals, including the ICTY,48 the International Criminal Tribunal for Rwanda (ICTR),49 the Special Court for Sierra Leone (SCSL),50 the Extraordinary Chambers in the (p. 114) Courts of Cambodia (ECCC),51 and the Special Tribunal for Lebanon (STL),52 none of which specify the sources of international criminal law or their hierarchy.53 In contrast, Article 21(1) of the Rome Statute of the International Criminal Court on ‘Applicable Law’ provides the following list of sources: a) first, the Statute, Elements of Crimes, and Rules of Procedure and Evidence; b) second, treaties, principles, and rules of international law; and c) failing that, general principles of law derived from laws of domestic legal systems, including those of the State that would normally have jurisdiction, as long as they are consistent with the Statute and with international law.54 This list differs from the one contained in Article 38(1) of the ICJ Statute in important respects. The Rome Statute, unlike the ICJ Statute, clearly contains a hierarchy as to the application of the sources—the ICC must first look to its own ‘internal’ or ‘proper’ sources (the Statute, Elements, Rules, and its own case law), then to other treaties and public international law rules, and to the general principles of law only if those still do not yield an answer.55 While there is no mention of the teachings of publicists or the jurisprudence of municipal and international tribunals, Article 21(2) authorizes the Court to ‘apply principles and rules of law as interpreted in its previous decisions’.

This has not, however, prevented the ICC from turning to publicists, both to develop and interpret the provisions of the Rome Statute and to add heft to its decisions. While some of these uses of doctrine appear relatively banal, there are other areas of international criminal law, such as modes of liability, where the Court has pioneered an altogether different use of the teachings of publicists as a source of international criminal law.

B.  The Role of Scholarship in the Jurisprudence on Modes of Liability

Few aspects of international criminal law have been as deeply contested as the modes of liability for attribution of conduct to the accused. In a remarkable exercise of interpretive creativity, the ICTY (headed by judge and scholar extraordinaire Antonio Cassese) was responsible for pioneering the doctrine of joint criminal enterprise (JCE) as a form of principal responsibility for the collective criminality that characterizes international (p. 115) crimes.56 The JCE doctrine has since been subject to extensive commentary and criticism,57 and there was much speculation on whether it will be endorsed by the ICC, especially since the Rome Statute has a detailed provision on modes of liability that does not, on the face of it, include JCE.58

In its first pronouncement on modes of liability in the Lubanga confirmation of charges decision, the ICC belied expectations by comprehensively rejecting JCE as a potential form of principal liability under the Statute and introducing the doctrines of co-perpetration and indirect perpetration into international criminal law in its place.59 In Lubanga, the Pre-Trial Chamber purported to adopt a textual interpretation of Article 25(3)(a) of the Rome Statute. It noted different approaches to distinguishing between parties to a crime: objective (physical commission of the objective elements of the crime); subjective (the mental state accompanying the contribution to the crime); and ‘control’ (the decision on whether and how the offence will be committed). According to the Chamber, the doctrine of ‘control’ over the crime was expressly included in the provision on liability for indirect perpetration in Article 25(3)(a) of the Rome Statute.60 Thus, the notion of ‘co-perpetration’ in the same article had to cohere with this criterion for differentiating between principals and accessories.61

The Lubanga Pre-Trial Chamber then specified the objective and subjective elements of co-perpetration, which have formed a template for subsequent iterations of the elements by the Pre-Trial Chamber. The objective elements consist of, first, an agreement or a common plan between two or more persons. This plan can be implicit and should include an element of criminality, even though it need not be directed specifically at the commission of a crime.62 Second, there must be a coordinated essential contribution by (p. 116) each perpetrator resulting in the realization of the objective elements of the crime.63 The first subjective element for co-perpetration is the accused’s fulfillment of all subjective elements of the crime with which he is charged. For most crimes under the jurisdiction of the ICC, this would mean meeting the ‘intent’ and ‘knowledge’ requirements in Article 30(1) of the Rome Statute.64 All co-perpetrators must also be mutually aware of and accept that the execution of the common plan may result in the realization of the objective elements of the crime.65 Finally, the accused must be aware of the factual circumstances enabling him to jointly control the crime.66

In the decision of confirmation of charges in Katanga and Ngudjolo, the Pre-Trial Chamber endorsed and expanded upon the notion of control under Article 25(3)(a) developed in Lubanga.67 In Katanga and Ngudjolo, however, the Chamber focused on the elements of liability for joint perpetration through another person. The Chamber saw no merit in the defence’s argument that the phrase ‘jointly with another or through another person’ can include either ‘co-perpetration’ or ‘indirect perpetration’, but not ‘indirect co-perpetration’.68 It then set out the objective elements for perpetration by (p. 117) means, concentrating on the cases that it considered most relevant to international criminal law: the doctrine of Organisationsherrschaft.69 These elements have been reiterated in subsequent Pre-Trial Chamber Confirmation of Charges decisions.70

The first element consists of the perpetrator’s control over the organization.71 The Katanga and Ngudjolo Pre-Trial Chamber opined that since Article 25(3)(a) expressly provided for the commission of a crime through another culpable person, it would also encompass cases involving the principal’s control over an organization.72 The second element is the existence of an organized and hierarchical apparatus of power.73 The third element is execution of the crimes through ‘automatic’ compliance with orders.74

There has been a significant amount of academic writing critically assessing the merits of the ICC’s jurisprudence on indirect and co-perpetration.75 However, for the purposes of this chapter, far more intriguing are the sources the ICC has relied on to put forward indirect and co-perpetration as an appropriate exegetical result and to define the elements of these modes of liability. The doctrines are a clear instance of borrowing from civil law doctrines of perpetration, in particular from the German criminal law system, where they originated in the work of prominent German criminal law theorists tasked with developing the Dogmatik of German criminal law.76 The very framework for the distinction between parties to a crime (subjective, objective, and control) is taken from German scholarship,77 and the concept of ‘control’ to distinguish between perpetrators and accessories was initially developed by German scholar Claus Roxin.78 The indebtedness of the doctrines to German criminal law scholarship is evident in the citations in the Lubanga confirmation of charges decision.79 Tracking back the references produces even more striking results—most of the academic sources cited by the Pre-Trial Chamber in turn rely on the conceptual framework for perpetration recog(p. 118) nized in German doctrine and inspired by one major author: Claus Roxin.80 Thus, even the scholarly chorus that undergirds the Pre-Trial Chamber’s analysis is heavily influenced by the ideas and writings of one towering intellectual figure, who is subsequently taken to represent an academic majority or consensus.81

Equally striking is the absence of references to almost any other sources. There is a passing reference to Judge Schomburg’s Opinions in the Gacumbitsi case at the ICTR and to the Stakić trial judgment at the ICTY.82 It is perfectly legitimate for the Pre-Trial Chamber to refer to the jurisprudence of the ad hoc tribunals, which is of persuasive value. However, Judge Schomburg’s reasoning also shows the clear influence of German scholarship. There are several direct references in the Opinion to the work of Roxin,83 and tracing back numerous other citations reveals Roxin as an important source of inspiration. For instance, Judge Schomburg cites the adoption of the concept of indirect perpetration by the German Federal Supreme Court (Bundesgerichtshof) in the Politbüro case, for which the original source is the work of Roxin.84 Similarly, his reference to the Argentinian National Appeals Court’s endorsement of the doctrine of indirect perpetration in the Argentine Juntas case85 fails to acknowledge the overwhelming influence of German criminal law doctrine and theorists, including Roxin, on the Argentinian law dealing with modes of criminal responsibility.86

This pattern of references is repeated in the Katanga and Ngudjolo confirmation of charges decision, where nearly all the citations are to the Pre-Trial Chamber’s decision in Lubanga and to German scholarship,87 with the occasional nod to judicial decisions by a few national courts.88 Yet again, though, Claus Roxin is the Chamber’s (p. 119) ‘crown witness’.89 When it comes to modes of liability at the ICC then, all roads eventually lead to Roxin and his adherents. The various elements of the modes of co-perpetration and indirect perpetration resemble their original counterparts in German criminal law doctrine, with only very few departures, such as the ability of the indirect perpetrator to secure automatic compliance with his orders based not on the element of fungibility of the direct perpetrators, but through intensive and violent training regimens for subordinates.90

The almost exclusive reliance on scholars varies markedly from the jurisprudence of the ad hoc tribunals, where surveys of the citation practice of the ICTY, for instance, have concluded that the influence of doctrine on the decision-making of the ICTY is marginal.91 This is not a particularly surprising conclusion, given that the ad hoc tribunals have been at pains to signal their adherence to the doctrine of sources in Article 38(1) of the ICJ Statute and have emphasized the ‘subsidiary’ character of the sources listed in Article 38(1)(d).92 The difference in approach between the ICC and the ad hoc tribunals suggests that the turn to doctrine for fleshing out modes of liability at the ICC cannot be fully accounted for by the fact that the traditional sources of public international law are silent on this question.

It is important to note that while the doctrines of co-perpetration and indirect perpetration are perfectly plausible interpretations of the text of Article 25(3), they are far from the only logical interpretation. As Van Sliedregt notes, contrary to the claims of the Pre-Trial Chamber in Lubanga, the drafting history of Article 25(3) suggests no single coherent doctrinal grounding for the modes of liability as a whole.93 The ostensibly textual interpretation has also been questioned by Judge Van den Wyngaert, whose Concurring Opinion in the Ngudjolo case94 challenges the derivation of the control theory from (p. 120) German legal doctrine. According to Judge Van den Wyngaert, this appropriation of the control theory violates both Article 31(1) of the Vienna Convention on the Law of Treaties, under which the court should interpret treaty terms according to their ‘ordinary meaning’95 as well the principles of strict construction and in dubio pro reo enshrined in Article 22(2) of the Rome Statute. This would be true even if the control theory could be regarded as a ‘general principle of criminal law’ under Article 21(1)(c), that is highly doubtful.96 There is, however, an alternative explanation for the adoption of the control theory by the ICC, which lies in the doctrine of sources.

IV.  The Reliance on Doctrine

On the face of it, the ICC’s resort to doctrine is merely an effort in treaty construction where it fleshes out the full meaning and import of the terms of the Rome Statute. However, the intricate liability structure that it produces scarcely resembles the everyday business of treaty interpretation. Indeed, it comes much closer to a technique that is much more common in civil law systems such as Germany: the heavy reliance on the Dogmatik to structure and understand the law.

A.  Scholars and the Dogmatik

In an illuminating observation on the ICC’s jurisprudence, George Fletcher attempts to explain the interpretive stance of the Pre-Trial Chamber’s Lubanga and Katanga and Ngudjolo Confirmation Decisions as an attempt to develop a Dogmatik, or a ‘set of values and principles that provide the structure of a code of criminal law’97 on principles of liability based on the jurisprudence of scholars. As Fletcher notes, if the ICC were to follow this methodology consistently, it would involve a move away from strict adherence to the terms of the statute towards interpreting it in light of a Dogmatik that evolves through the jurisprudence of the ICC and scholars.98 Fletcher’s cursory remarks, however, pave the way to a more considered examination of whether the influence of the civilian tradition of sources of law and interpretation, in particular the role of scholars in the process, might signify a shift in the way doctrine will be used to develop international law, at least in the specific field of international criminal law.

(p. 121) An idea of what this might entail can be obtained from looking at the esteem in which ‘doctrine’ is held in civil law traditions such as Germany, both historically and in the contemporary legal system. While scholarship or doctrine is by no means an official source of law, the concept of Lehre (teachings or ‘theory’) is integral to the systematization of the law.99 The herrschende Lehre (dominant teachings) are not enacted law, but being as they are, statements and theories about the basic legal principles that lend structure and coherence to the law as a whole, they are highly persuasive in judicial reasoning and decision-making.100 Indeed, in the case of a gap in the law, some modern codes explicitly authorize judges to rely on ‘established doctrine’.101 The doctrine serves various functions, including providing answers to specific cases, critiquing the existing jurisprudence with the explicit aim of developing the law, and uncovering fundamental conceptual and structuring principles.102

This tradition of the high value placed on the writings of scholars has its origins in pre-classical and classical Roman law and stretches into the emergence of the modern civil law systems in the twelfth century, where the systematic study and exposition of the law at centres of learning had a significant influence on the judicial process.103 Professors were cited extensively by advocates, asked to weigh in on complex cases, and even used as a way for judges to avoid personal liability for potentially wrong judgments!104 The main features of this intellectual heritage persist till the present and scholars continue to be extremely influential in civil law as well as mixed-legal systems.105

The ICC’s jurisprudence on modes of liability owes much to a similar appropriation of doctrine (that is, moreover, not international but domestic in nature) whereby the systematizing function of scholarship constitutes a de facto source of law. What could account for this approach to the authoritativeness of doctrine?

B.  Scholars and their relationship to international criminal law

Possible explanations for why the teachings of publicists have ascended to the status of a dominant legal source in the ICC’s jurisprudence on forms of responsibility must take (p. 122) into account the distinctly ‘scholarly’ background of the development of the institutions of international criminal justice. In the beginning of the revival of international criminal law in the 1990s, prominent public international law academics such as Cherif Bassiouni played a central role in the establishment and design of international criminal tribunals such as the ICTY.106 The influence of public international law scholars was apparent in the academic spirit and style of ICTY judgments spearheaded by judge-academic Antonio Cassese, whose reputation as a public international law scholar was eclipsed only by his role in the development of the early jurisprudence of the ICTY.107 Bassiouni and other prominent scholars were also instrumental in the drafting of the Rome Statute of the ICC; and the subsequent phase of the maturing of international criminal law has witnessed the growing participation of scholars with a primarily criminal law background.108 The composition of this ‘invisible college’ of international criminal law scholars has also shifted and now includes academics from traditionally under-represented parts of the globe, including Eastern Europe, Asia, and Africa.109

Scholars continue to occupy a crucial role in the discourse of international criminal justice, not only due to their advisory role in significant processes such as the negotiations leading to the definition of the crime of aggression,110 but also because of the revolving door that characterizes the practice of international criminal law.111 From the very inception of international criminal tribunals, there has been a close connection between lawyer-academics who move between important roles in government or academia and then go on to careers as lawyers and judges in international courts, and sometimes return to yet more illustrious careers in policy positions in their home countries.112 The quasi-academic pedigree of the ad hoc tribunals and the ICC, and the scholarly background of influential individual lawyers and judges who have played important roles in the formulation and application of international criminal legal rules might explain their readiness to turn to doctrine as a source of inspiration or authority.

The nature of scholarship in international criminal law is also quite varied and serves a multitude of purposes: theoretical/conceptual systematization, doctrinal construction, value-oriented activism, critical reflection, and empirical evaluation.113 The conceptual and normative focus of a good proportion of international criminal law scholarship may in fact be one of the contributing factors in its influence on the jurisprudence of the (p. 123) international criminal tribunals, especially given the relatively underdeveloped state of the principles governing international criminal law, even by the time the ICC was established and began to function.

In some ways, this reliance on non-traditional sources to promote and develop (rather than merely serve as evidence of) the law is not unique to the ICC. For instance, scholars have pointed to rare instances where individual opinions of judges at the ICJ cite the teachings of publicists to similar effect.114 In the context of international criminal law, scholar-judges such as Antonio Cassese early on pioneered a ‘critical positivism’ in their approach to finding and developing the principles of international criminal law.115 For Cassese, an international jurist faced with the indeterminacy of the law was justified in drawing on general principles that expressed (purportedly) universal values such as peace, democracy, and the rule of law to make an explicit choice between conflicting legal claims based on extra-legal considerations.116 Cassese has been compared to Lauterpacht in his approach to the progressive interpretation of law that is nevertheless grounded in a largely positivist framework.117 This can be seen, for instance, in his heavy emphasis on the element of opinio juris as compared to state practice for the identification of rules of customary international law.118 The readiness to harness sources of law that fall outside the hierarchy of the formal sources of public international law has meant that subsidiary actors, such as judges and scholars, have assumed an unusually authoritative role in the creation and interpretation of the rules of international criminal law.119 In the absence of any sophisticated pre-existing international criminal law framework, their task has often not been one of mere identification of the law, but that of conceptually oriented and value-laden development of the rules governing international criminal law.120

(p. 124) V.  Conclusion

Does the newfound importance given to doctrine in the development of modes of liability imply that in contrast to traditionally state-made public international law, international criminal law, at least in specialized areas, can be characterized as professor-made? This would be too rigid a dichotomy. The ICC’s reliance on the teachings of publicists to develop an international law framework on modes of liability is but one instance of the emergence of doctrine as a de facto source of law, that may end up being limited to this highly technical criminal-law-specific area of the law. Indeed, one can argue that even when it comes to the elements of perpetration responsibility, after an initial embrace of doctrine as a source of law, the ICC has subsequently chosen to cite its own previous decisions on the requirements for liability as a perpetrator and largely refrained from referring to academic commentary.121 In doing so, the Court is clearly on firmer ground: under Article 21(2) the Court may apply ‘principles and rules of law as interpreted in its previous decisions’. This contrast in the use of sources is nevertheless striking, especially when one considers that there is now a rich discussion on modes of responsibility by international criminal law scholars, and the Court could thus avoid charges of relying exclusively on select domestic law debates. Should this pattern of references continue, in time, the original academic source of the elements of perpetration responsibility is likely to be obscured.

Alternatively, the turn to jurists could signal a broader recognition by judges of the need to go beyond the official catalogue of sources in the Rome Statute, that very often do not contain concrete answers to the specific legal questions the Court confronts. For instance, a similar reliance on doctrine is noticeable in decisions and individual opinions on the elements required to establish the existence of crimes against humanity under Article 7 of the Rome Statute.122 In traditional public international law, however, the teachings of publicists are intended to serve this gap-filling function only indirectly, by providing material evidence that meets the criteria for establishing the ‘formal’ sources of law. To do otherwise may run counter to the principle of legality enshrined in the Rome Statute, which includes the prohibition against ex post facto criminalization, strict construction of crime definitions and restriction on extensions by analogy, and (p. 125) the rule of in dubio pro reo.123 The Court could potentially still rely on the systematizing function of ‘doctrine’ to lend structure and coherence to the criminal law enshrined in the Rome Statute; after all, civil law systems that embrace this role played by doctrine in their criminal law systems manage to do so without jeopardizing their compliance with the principle of legality. If the Court chooses to traverse this path, it would need to address far more explicitly the scope and nature of the Dogmatik and its interpretive function within the framework of the Rome Statute. In particular, the Court will need to be conscious of the limits of using scholarship developed in the context of domestic legal systems to craft a Dogmatik for international criminal law.

The Court could also use the teachings of publicists on international criminal law, as a ‘documentary’ or ‘law-determining’ source, which serves to evidence the existence of the ‘formal’ sources in Article 21(1) of the Rome Statute. Doctrine could prove useful in identifying the existence of ‘principles and rules of international law’ and ‘general principles of law derived from laws of domestic legal systems’. In this exercise, the Court must, however, be careful to distinguish between commentary that truly highlights the evidentiary basis for the ascertainment of the formal sources and scholarship that is more normative in character.

In general public international law, an influential strain of scholarship has long been skeptical of the ‘ruleness’ of sources of law, especially of those that are considered formal sources.124 Thus, rather than identifying a single rule of recognition for international law,125 scholars have pushed for an emphasis on the social practice of authorities tasked with applying the law. Under this understanding, what qualifies as a source of law will depend as much on an act of interpretation by the relevant law-applying authority, as does the content of the law. Moreover, as this social practice shifts and evolves, so will the criteria for law-ascertainment.126 The ICC’s jurisprudence to date indicates that the Court is still formulating its position on legal sources, their hierarchy, and their interpretation.127 In this process, the Court will also be interpreting Article 21(1), which outlines the sources of law. As the ICC continues to engage in this exercise, its pronouncements are likely to constitute one of the most significant arbiters of what counts as a source of international criminal law, not only for the purposes of the Rome Statute, but also for the broader field of international criminal law.(p. 126)


1  Associate Professor of Law, University of Minnesota Law School; Fellow, Stellenbosch Institute for Advanced Study (STIAS), Wallenberg Research Centre at Stellenbosch University, Stellenbosch 7600, South Africa. I am indebted to the Editors of the Handbook for detailed and helpful feedback on this chapter.

2  This assumption underlies even the most sophisticated work on the sources of international criminal law. See e.g., Antonio Cassese, International Criminal Law (OUP 2003) 20, 26 (hereafter Cassese, ICL); Dapo Akande, ‘Sources of International Criminal Law’ in Antonio Cassese (ed), The Oxford Companion to International Criminal Justice (OUP 2009) 41; Margaret McAullife deGuzman, ‘Article 21: Applicable Law’ in Otto Triffterer (ed), Commentary on the Rome Statute of the International Criminal Court (2nd edn, Beck, Hart, and Nomos 2008) 701, 702.

3  Cassese, ICL (n 1) 18–19; Leena Grover, ‘A Call to Arms: Fundamental Dilemmas Confronting the Interpretation of Crimes in the Rome Statute of the International Criminal Court’ (2010) 21 European J of Intl L 543, 550–51.

4  Scholars have increasingly turned their attention to the centrality of judicial creativity in the development of international criminal law. See e.g., Shane Darcy and Joseph Powderly (eds), Judicial Creativity at the International Criminal Tribunals (OUP 2010); Antonio Cassese, ‘Black Letter Lawyering v. Constructive Interpretation’ (2004) 2 J of Intl Crim Justice 265; William Schabas, ‘Interpreting the Statutes of the ad hoc Tribunals’ in Lal Chand Vohrah and others (eds), Man’s Inhumanity to Man: Essays on International Law in Honour of Antonio Cassese (Kluwer Law International 2003) 847.

5  For a recent exception to this trend in general public international law, see Lianne J M Boer, ‘ “The Greater Part of Jurisconsults”: On Consensus Claims and Their Footnotes in Legal Scholarship’ (2016) 29(4) Leiden J of Intl L 1021 (hereafter Boer, ‘Consensus Claims’).

6  Mia Swart, ‘Judicial Lawmaking at the ad hoc Tribunals: The Creative Use of the Sources of International Law and “Adventurous Interpretation” ’ (2010) 70 Zeitschrift für Aüslandisches öffentliches Recht und Völkerrecht 459, 463–48; Guénaël Mettraux, International Crimes and the Ad Hoc Tribunals (OUP 2005) 13–15; André Nollkaepmer, ‘The Legitimacy of International Law in the Case Law of the International Tribunal for the Former Yugoslavia’ in Thomas A J A Vandamme and Jan Herman Reestman (eds), Ambiguity in the Rule of Law: The Interface Between National and International Legal Systems (Europa Law 2001) 13, 17.

7  André Nollkaepmer, ‘Decisions of National Courts as Sources of International Law: An Analysis of the Practice of the ICTY’ in Gideon Boas and William Schabas (eds), International Criminal Law Developments in the Case Law of the ICTY (Brill 2003) 277.

8  For uncommon attempts to relate the sources of international criminal law to the hybrid identity of the regime, see Leena Grover, Interpreting Crimes in the Rome Statute of the International Criminal Court (CUP 2014) (on treaty interpretation in the context of international criminal law); Neha Jain, ‘Judicial Lawmaking and General Principles of Law in International Criminal Law’ (2016) 57 Harvard Intl L J 111 (on the general principles of law in international criminal law).

9  Rome Statute of the International Criminal Court, 17 July 1998, 2187 UNTS 90, UN Doc A/CONF.183/9 (in force 1 July 2002), art 21 (hereafter Rome Statute). This viewpoint could partially be explained by the fact that the Rome Statute is a self-contained treaty regime that has its own hierarchy of sources. However, the same could be said for Art 38 of the ICJ Statute, that has been a vital reference point for any discussion of the sources doctrine in public international law more broadly.

10  David Kennedy, ‘The Sources of International Law’ (1987) 2 American U Intl L Rev 1, 2; Robert Jennings, ‘What is International Law and How Do We Tell It When We See It?’ (1981) 37 Schweizerisches Jahrbuch für Internationales Recht 59, 60–61.

11  Statute of the International Court of Justice, 26 June 1945, 3 UST 1179, 59 US Stat 1031, art 38(1)(d).

12  Permanent Court of Justice, Advisory Committee of Jurists, Procés-Verbaux of the Proceedings Committee, June 16thJuly 24th 1920 (Van Langenhuysen 1920) Annex No 3 at 306 <https://archive.org/details/procsverbauxof00leaguoft> accessed 2 July 2018 (hereafter Procès-Verbaux).

13  Procés-Verbaux (n 11) 318–19, 323. See also Alain Pellet, ‘Article 38’ in Andreas Zimmermann and others (eds), The Statute of the International Court of Justice: A Commentary (OUP 2006) 677, 686 (hereafter Pellet, ‘Article 38’); Michael Peil, ‘Scholarly Writings as a Source of Law: A Survey of the Use of Doctrine by the International Court of Justice’ (2012) 1 Cambridge J of Intl and Comparative L 136, 138–39 (hereafter Peil, ‘Scholarly Writings’).

14  Procés-Verbaux (n 11) 344.

15  For a detailed account, see Pellet, ‘Article 38’ (n 12) 685–88; Maarten Bos, ‘The Recognized Manifestations of International Law: A New Theory of “Sources” ’ (1997) 20 German YB of Intl L 9, 61–63 (hereafter Bos, ‘New Theory’); Peil, ‘Scholarly Writings’ (n 12) 138–40.

16  Procés-Verbaux (n 11) 332–34.

17  Procés-Verbaux (n 12) 333, 336.

18  Procés-Verbaux (n 11) 336.

19  Procés-Verbaux (n 11) 332, 334.

20  Procés-Verbaux (n 11) 584.

21  Bos, ‘New Theory’ (n 14) 62–63; Peil, ‘Scholarly Writings’ (n 11) 140. cf Pellet, ‘Article 38’ (n 11) 783 (concluding that notwithstanding the confusing positions adopted by various members, the final draft signalled their intention to retain doctrine as a means to elucidate the rules to be applied by the court).

22  For a detailed discussion and references, see Aldo Zammit Borda, ‘A Formal Approach to Article 38(1)(d) of the ICJ Statute from the Perspective of the International Criminal Court and Tribunals’ (2013) 24 European J of Intl L 649, 653–56 (hereafter Borda, ‘Formal Approach to Article 38(1)(d)’).

23  Sir Gerald G Fitzmaurice, ‘Some Problems Regarding the Formal Sources of International Law’ in Jan H W Verzijl (ed), Symbolae Verzijl: Presentées au Professor J.H.W. Verzijl à l’occasion de son LXX-ième anniversaire (Nijhoff 1958) 153, 153–54 (hereafter Fitzmaurice, ‘Problems Regarding the Formal Sources’); Shabtai Rosenne, The Law and Practice of the International Court, 1920–2005, vol III (Nijhoff 2006) 1551.

24  Georg Schwarzenberger, ‘The Province of the Doctrine of International Law’ (1956) 9 Current Legal Problems 235, 236–37 (hereafter Schwarzenberger, ‘The Province of the Doctrine’); Georg Schwarzenberger, ‘The Inductive Approach to International Law’ (1947) 60 Harvard L Rev 539, 550–51 (hereafter Schwarzenberger, ‘Inductive Approach’).

25  Fitzmaurice, ‘Problems Regarding the Formal Sources’ (n 22) 172–74; Borda, ‘Formal Approach to Article 38(1)(d)’ (n 21) 650, 660. cf Torsten Gihl, ‘The Legal Character and Sources of International Law’ (1957) 1 Scandinavian Studies in Law 51, 74 (referring with approval to their equal status under the ICJ statute and arguing that their influence should depend equally on the quality of their arguments).

26  Fitzmaurice, ‘Problems Regarding the Formal Sources’ (n 22) at 172.

27  ibid 172–74. Robert Jennings, ‘The Judiciary, International and National, and the Development of International Law’ (1996) 45 Intl and Comparative L Q 1, 9 (hereafter Jennings, ‘The Judiciary’).

28  Jörg Kammerhofer, ‘Lawmaking by Scholars’ in Catherine Brölmann and Yannick Radi (eds), Research Handbook on the Theory and Practice of International Lawmaking (Elgar 2016) 305, 308. cf Pellet, ‘Article 38’ (n 12) 748 (arguing that although doctrine and jurisprudence perform the same function in the abstract, the ICJ’s use of the two sources has been quite different). See also P K Menon, ‘An Enquiry into the Sources of Modern International Law’ (1986) 64 Revue de Droit International, de Sciences Diplomatiques et Politiques 181, 199 (on the differential treatment of the two sources by the PCIJ and the ICJ).

29  Robert Jennings, ‘Reflections on the Subsidiary Means for the Determination of Rules of Law’ (2003) 1 Studi di diritto internazionale in onore di Gaetano Arangio-Ruiz 319, 327–28 (hereafter Jennings, ‘Reflections’); Pellet, ‘Article 38’ (n 12) 791–92. See also Peil, ‘Scholarly Writings’ (n 12) 144–47 (Peil examines the possible reasons for the reluctance to cite scholars).

30  Manfred Lachs, The Teacher in International Law: Teachings and Teaching (Nijhoff 1982) 172–73 (hereafter Lachs, Teacher); Jennings, ‘Reflections’ (n 28) 328.

31  The Renard (1778) Hay-Marriott 222–224; 165 English L Rep 51, 52 (Adm).

32  Pellet, ‘Article 38’ (n 12) 792; Hilary Charlesworth, ‘Law-Making and Sources’ in James Crawford and Martti Koskenniemi (eds), The Cambridge Companion to International Law (CUP 2012) 187, 197 (hereafter Charlesworth, ‘Law-Making and Sources’); Jennings, ‘The Judiciary’ (n 26) 9.

33  Clive Parry, The Sources and Evidences of International Law (Oceana 1965) 104–05, 108 (hereafter Parry, Sources and Evidences); Schwarzenberger, ‘Inductive Approach’ (n 23) 560–62. See also Nicholas Greenwood Onuf, ‘Law-Making in the Global Community (1974)’ in Nicholas Greenwood Onuf (ed), International Legal Theory: Essays and Engagements 1966–2006 (Routledge-Cavendish 2008) 63, 71.

34  Lachs, Teacher (n 29) 176–77; Gleider I Hernández, ‘The Responsibility of the International Legal Academic: Situating the Grammarian within the “Invisible College” ’ in Nollkaemper and others (eds), International Law as a Profession (CUP 2017) 1, 20–1 (hereafter Hernández, ‘Responsibility’); Bos, ‘New Theory’ (n 14) 63.

35  Lassa Oppenheim, ‘The Science of International Law: Its Task and Method’ (1908) 2 American J of Intl L 313, 315, 345 (hereafter Oppenheim, ‘Science of International Law’); Gillian Triggs, ‘The Public International Lawyer and the Practice of International Law’ (2005) 24 Australian YB of Intl L 201, 202 (hereafter Triggs, ‘Public International Lawyer’).

36  Parry, Sources and Evidences (n 32) 103.

37  Hernández, ‘Responsibility’ (n 33) 20.

38  Parry, Sources and Evidences (n 32) 107. cf Triggs, ‘Public International Lawyer’ (n 35) 202–03 (citing examples where tribunals have rejected ‘progressive lawyering’ by scholars where their assertions have not been backed by evidence).

39  Lachs, Teacher (n 29) 167; Triggs, ‘Public International Lawyer’ (n 34) 205–06.

40  See Robert Jennings, ‘International Lawyers and the Progressive Development of International Law’ in Jerzy Macarczyk (ed), Theory of International Law at the Threshold of the 21st Century: Essays in Honour of Krzystof Skubiszewski (Kluwer Law International 1996) 417; Triggs, ‘Public International Lawyer’ (n 34) 205–06.

41  Lachs, Teacher (n 29) 194–95.

42  See Fernando Lusa Bordin, ‘Reflections of Customary International Law: The Authority of Codification Conventions and ILC Draft Articles in International Law’ (2014) 63 Intl and Comparative L Q 535, 536, 538–39 (hereafter Bordin, ‘Reflections’).

43  Peil, ‘Scholarly Writings’ (n 12) 152.

44  Bordin, ‘Reflections’ (n 41) 552, 549–48.

45  ibid 544; Pellet, ‘Article 38’ (n 12) 757–58 citing Gabčíkovo-Nagymaros Project (Hungary v Slovakia), Judgment, [1997] ICJ Rep 7, 38–42, paras 47, 50–4.

46  ibid paras 49–58.

47  Bordin, ‘Reflections’ (n 41) 544–45 citing Application of the Convention on the Prevention and Punishment of the Crime of Genocide (Bosnia and Herzegovina v Serbia and Montenegro), Judgment, [2007] ICJ Rep 43, para 385, 398, 420, 431; Pulp Mills on the River Uruguay (Argentina v Uruguay), Judgment, [2010] ICJ Rep 14, para 273; Ahmadou Sadio Diallo (Republic of Guinea v Democratic Republic of the Congo), Preliminary Objections, Judgment, [2007] ICJ Rep 582, paras 31, 91.

48  Statute of the International Criminal Tribunal for the Former Yugoslavia, UNSC Res 827, UNSCOR, 48th Sess, 3217th Mtg, UN Doc S/RES/827 (25 May 1993) (hereafter ICTY Statute).

49  Statute of the International Criminal Tribunal for Rwanda, UNSC Res 955, UNSCOR, 49th Sess, 3453rd Mtg, UN Doc S/RES/955, (8 November 1994).

50  UN Secretary-General, Report on the Establishment of a Special Court for Sierra Leone, UNSCOR, 55th Sess, UN Doc S/2000/915, (4 October 2000).

51  Agreement Between the United Nations and the Royal Government of Cambodia Concerning the Prosecution Under Cambodian Law of Crimes Committed During the Period of Democratic Kampuchea, UNGA Res 57/228, UN Doc A/RES/57/228B/Annex (13 May 2003); Law on the Establishment of Extraordinary Chambers in the Courts of Cambodia for the Prosecution of Crimes Committed During the Period of Democratic Kampuchea, NS/RKM/1004/006 (27 October 2004).

52  Statute of the Special Tribunal for Lebanon, UNS Res 1757, UN Doc S/RES/1757 (30 May 2007).

53  Gilbert Bitti, ‘Article 21 of the Statute of the International Criminal Court and the Treatment of Sources of Law in the Jurisprudence of the ICC’ in Carsten Stahn and Göran Sluiter (eds), The Emerging Practice of the International Criminal Court (Brill 2009) 285, 286–87 (hereafter Bitti, ‘Article 21’).

54  Rome Statute (n 8) art 21.

55  Bitti, ‘Article 21’ (n 52) 287–88. See also Allain Pellet, ‘Applicable Law’ in Antonio Cassese, Paola Gaeta, and John R W D Jones (eds), The Rome Statute of the International Criminal Court: A Commentary, vol II (OUP 2002) 1051, 1053–54 (hereafter Cassese and others (eds), The Rome Statute).

56  The Prosecutor v Tadić (Judgment) IT-94-1-A, (15 July 1999) paras 187–93 (ICTY, Appeals Chamber).

57  See e.g., Allison Marston Danner and Jenny S Martinez, ‘Guilty Associations: Joint Criminal Enterprise, Command Responsibility, and the Development of International Criminal Law’ (2005) 93 California L Rev 75; Gideon Boas, James Bischoff, and Natalie Reid, International Criminal Law Practitioner Library, Vol I: Forms of Responsibility in International Criminal Law (CUP 2008) 8–141; Jens David Ohlin, ‘Three Conceptual Problems with the Doctrine of Joint Criminal Enterprise’ (2007) 5 J of Intl Crim Justice 69.

58  See e.g., Florian Jessberger and Julia Geneuss, ‘On the Application of a Theory of Indirect Perpetration in Al Bashir: German Doctrine at the Hague?’ (2008) 6 J of Intl Crim Justice 853, 865 (predicting that the ICC may be willing to interpret accessory liability under art 25(3)(d) as a ‘little cousin’ of JCE); Thomas Weigend, ‘Intent, Mistake of Law and Co-Perpetration in the Lubanga Decision on Confirmation of Charges’ (2008) 6 J of Intl Crim Justice 471, 478 (remarking that Art 25(3)(d) ‘cracks open the door’ on JCE); Linda Engvall, ‘The Future of Extended Joint Criminal Enterprise – Will the ICTY’s innovation meet the standards of the ICC?’ (2007) 76 Nordic J of Intl L 241, 258 (arguing that JCE may be split between para (a) and para (d) of Art 25).

59  The Prosecutor v Lubanga (Decision on the Confirmation of Charges) ICC-01/04–01/06, (26 January 2007) (Pre-Trial Chamber I) (hereafter Lubanga (Confirmation of Charges)).

60  ibid paras 328–35, 338–39.

61  ibid paras 331–32, 349–50.

62  ibid paras 343–45; The Prosecutor v Katanga and Ngudjolo Chui (Decision on the Confirmation of Charges) ICC-01/04–01/07, (30 September 2008) paras 522–23 (Pre-Trial Chamber I) (hereafter Katanga and Ngudjolo Chui (Confirmation of Charges)); The Prosecutor v Muthaura, Kenyatta and Ali (Decision of the Confirmation of Charges Pursuant to Article 61(7)(a) and (b) of the Rome Statute) ICC-01/09–02/11, (23 January 2012) paras 399–400 (Pre-Trial Chamber II) (hereafter Muthaura, Kenyatta and Ali (Confirmation of Charges)); The Prosecutor v Banda and Jerbo (Corrigendum of the Decision on the Confirmation of Charges) ICC-02/05–03/09, (7 March 2011) paras 129–35 (Pre-Trial Chamber I) (hereafter Banda and Jerbo (Confirmation of Charges)); The Prosecutor v Ruto, Kosgey and Sang (Decision of the Confirmation of Charges Pursuant to Article 61(7)(a) and (b) of the Rome Statute) ICC-01/09–01/11, (23 January 2012) paras 301–04 (Pre-Trial Chamber II) (hereafter Ruto, Kosgey and Sang (Confirmation of Charges)); The Prosecutor v Abu Garda (Corrigendum of the Decision on the Confirmation of Charges) ICC-02/05–02/09, (8 February 2010) paras 160, 163–232 (Pre-Trial Chamber I) (hereafter Abu Garda (Confirmation of Charges)).

63  Lubanga (Confirmation of Charges) (n 58) paras 346–48; Katanga and Ngudjolo Chui (Confirmation of Charges) (n 61) paras 524–26; Muthaura, Kenyatta and Ali (Confirmation of Charges) (n 61) paras 401–06; Banda and Jerbo (Confirmation of Charges) (n 61) paras 136–49; Ruto, Kosgey and Sang (Confirmation of Charges) (n 61) paras 305–12; Abu Garda (Confirmation of Charges) (n 61) paras 160, 180–232.

64  Lubanga (Confirmation of Charges) (n 58) paras 349–60. See also Katanga and Ngudjolo Chui (Confirmation of Charges) (n 61) paras 527–32; The Prosecutor v Bemba Gombo (Decision Pursuant to Article 61(7)(a) and (b) of the Rome Statute on the Charges of the Prosecutor Against Jean-Pierre Bemba Gombo) ICC-01/05–01/08, (15 June 2009) para 351 (Pre-Trial Chamber I) (hereafter Bemba Gombo (Confirmation of Charges)); Muthaura, Kenyatta and Ali (Confirmation of Charges) (n 61) paras 410–17; Ruto, Kosgey and Sang (Confirmation of Charges) (n 61) paras 333, 338–47; Abu Garda (Confirmation of Charges) (n 61) para 161; Banda and Jerbo (Confirmation of Charges) (n 61) paras 150–57.

65  Lubanga (Confirmation of Charges) (n 58) 361–65; Katanga and Ngudjolo Chui (Confirmation of Charges) (n 61) paras 533–37.

66  Lubanga (Confirmation of Charges) (n 58) 366–67; Bemba Gombo (Confirmation of Charges) (n 63) para 351; Banda and Jerbo (Confirmation of Charges) (n 61) paras 150, 160–61; Abu Garda (Confirmation of Charges) (n 61) para 161.

67  See Katanga and Ngudjolo Chui (Confirmation of Charges) (n 61) paras 480–86.

68  ibid paras 490–93. See also Ruto, Kosgey and Sang (Confirmation of Charges) (n 61) paras 287, 289 (stating that the concept of indirect co-perpetration was derived from merging the two modes of participation in Article 25(3)(a), that was a dynamic approach to interpretation in conformity with the Vienna Convention on the Law of Treaties); Abu Garda (Confirmation of Charges) (n 61) paras 156–57. See Thomas Weigend, ‘Perpetration through an Organization: The Unexpected Career of a German Legal Concept’ (2011) 9 J of Intl Crim Justice 91, 110 (hereafter Weigend, ‘Perpetration through an Organization’) (stating that there is nothing novel about this mode of liability that is merely a combination of two accepted modes of perpetration).

69  See Katanga and Ngudjolo Chui (Confirmation of Charges) (n 61) paras 495–99.

70  Muthaura, Kenyatta and Ali (Confirmation of Charges) (n 61) paras 407–10; Ruto, Kosgey and Sang (Confirmation of Charges) (n 61) paras 313–32.

71  See Katanga and Ngudjolo Chui (Confirmation of Charges) (n 61) paras 500–10; Muthaura, Kenyatta and Ali (Confirmation of Charges) (n 61) paras 407–10; Ruto, Kosgey and Sang (Confirmation of Charges) (n 61) paras 313–32.

72  Katanga and Ngudjolo Chui (Confirmation of Charges) (n 61) paras 501, 510.

73  ibid paras 511–14; Muthaura, Kenyatta and Ali (Confirmation of Charges) (n 61) para 408; Ruto, Kosgey and Sang (Confirmation of Charges) (n 61) 313–17.

74  See Katanga and Ngudjolo Chui (Confirmation of Charges) (n 61) paras 515–18; Muthaura, Kenyatta and Ali (Confirmation of Charges) (n 61) paras 409–10; Ruto, Kosgey and Sang (Confirmation of Charges) (n 61) paras 313–32.

75  For a comprehensive review and citations, see Neha Jain, Perpetrators and Accessories in International Criminal Law: Individual Modes of Responsibility for Collective Crimes (Hart 2014) 81–98.

76  See e.g., Johannes Wessels and Werner Beulke, Strafrecht, allgemeiner Teil: Die Straftat und ihr Aufbau (42th revised edn, C F Müller 2012) 190–208 (hereafter Wessels and Beulke); HW Laufhütte and others (eds), Strafgesetzbuch Leipziger Kommentar (Großkommentar): Band 1 (12th revised edn, De Gruyter 2007) 1844–964 (hereafter Leipziger Kommentar) (on the development and explication of the modes of liability in German criminal law).

77  Wessels and Beulke (n 75) 193–95; Leipziger Kommentar (n 75) 1846–60.

78  Claus Roxin, Täterschaft und Tatherrschaft (De Gruyter 2006) 60–126.

79  See e.g., Lubanga (Confirmation of Charges) (n 58) at fn 425 citing Roxin and a number of authors who share his view.

80  See e.g., Lubanga (Confirmation of Charges) (n 58) fn 418 citing Gerhard Werle, Principles of International Criminal Law (TMC Asser Press 2005) margin no 354 (who cites Kai Ambos, Der Allgemeine Teil des Völkerstrafrechts (Duncker & Humblot 2002) whose work in turn has numerous references to Roxin’s framework); Lubanga (Confirmation of Charges) (n 58) fn 418 citing George Fletcher, Rethinking Criminal Law (OUP 2000) 639 (whose primary citations are to German law and doctrine); Lubanga (Confirmation of Charges) (n 58) fn 419 citing Albin Eser, ‘Individual Criminal Responsibility’ in Cassese and others (eds), The Rome Statute (n 53) vol 1, 795 (who cites Friedrich-Christian Schroeder, Der Täter hinter dem Täter (Duncker & Humblot 1965), the precursor to Roxin’s theory of indirect perpetration).

81  This argument takes its inspiration from the methodological model developed in Lianne Boer’s work on consensus claims in the context of use of force. See Boer, ‘Consensus Claims’ (n 4) 1037–38.

82  Lubanga (Confirmation of Charges) (n 58) at fns 418, 422–24, 426, 432, 434, 436–37, 440, 442 citing The Prosecutor v Gacumbitsi (Judgment) ICTR-2001-64-A, (7 July 2006) (ICTR, Appeals Chamber, Separate Opinion of Judge Schomburg) (hereafter Gacumbitsi, Separate Opinion of Judge Schomburg); and The Prosecutor v Stakić (Trial Judgment) IT-97-24-T, (31 July 2003) (ICTY, Trial Chamber II).

83  Gacumbitsi, Separate Opinion of Judge Schomburg (n 81) fns 31–33, 37.

84  Gacumbitsi, Separate Opinion of Judge Schomburg (n 81) fns 35, 38 citing German Federal Supreme Court (Bundesgerichtshof), Judgment of 26 July 1994, BGHSt 40, 218, 236. On the Bundesgerichtshof’s adoption and expansion of Roxin’s theory, see Weigend, ‘Perpetration through an Organization’ (n 67) 94–95, 98–99.

85  Gacumbitsi, Separate Opinion of Judge Schomburg (n 81), fn 34 citing Judgement on Human Rights Violations by Former Military Leaders of 9 December 1985, [1987] 26 ILM 317–72.

86  Cassandra Steer, Translating Guilt: Identifying Leadership Liability for Mass Atrocity Crimes (Springer and TMC Asser Press 2017) 215, 217–19.

87  Katanga and Ngudjolo Chui (Confirmation of Charges) (n 61) at fns 640, 642, 645–46, 647, 649, 655–60, 664–65, 678, 680–84, 686, 689 (citing, amongst other commentators, Roxin).

88  Katanga and Ngudjolo Chui (Confirmation of Charges) (n 61) at fns 667, 679.

89  Weigend, ‘Perpetration through an Organization’ (n 67) 94.

90  Katanga and Ngudjolo Chui (Confirmation of Charges) (n 61) para 518. This addition to the element of fungibility is not found in the original German doctrine: see Weigend, ‘Perpetration through an Organization’ (n 67) 107 (critical of this position, stating that the Chamber may have found it necessary to adapt the doctrine to suit the exigencies of mass atrocity in Africa). cf Harmen van der Wilt, ‘The Continuous Quest for Proper Modes of Criminal Responsibility’ (2009) 7 J of Intl Crim Justice 307, 312 (arguing that this new element introduces flexibility in the doctrine).

91  Michael Bohlander, ‘The Influence of Academic Research on the Jurisprudence of the International Criminal Tribunal for the Former Yugoslavia–A First Overview’ (2004) 3 Global Community: YB of Intl L and Jurisprudence 195, 208. See also Michael Bohlander, ‘Language, Culture, Legal Traditions and International Criminal Justice’ (2004) 12(3) J of Intl Crim Justice 491, 502 (conducting a qualitative assessment of the overall citations in the Lubanga trial judgment to conclude that 88% were academic sources).

92  Borda, ‘Formal Approach to Article 38(1)(d)’ (n 21) 653 citing The Prosecutor v Zoran Kupreškić et al. (Judgment) IT-95-16-T, (14 January 2000) para 540 (ICTY Trial Chamber); and The Prosecutor v Issa Hassan Sesay, Morris Kallon, Augustine Gbao (Judgment) SCSL-04-15-T, (2 March 2009) para 295 (SCSL, Trial Chamber).

93  Elies van Sliedregt, Individual Criminal Responsibility in International Law (OUP 2012) 85–6; Jens David Ohlin, Elies van Sliedregt, and Thomas Weigend, ‘Assessing the Control-Theory’ (2013) 26 Leiden J of Intl L 725, 744–45.

94  The Prosecutor v Ngudjolo Chui (Judgment Pursuant to Article 74 of the Statute, Concurring Opinion of Judge Christine Van den Wyngaert) ICC-01/04–02/12, (8 December 2012) (Trial Chamber II) (hereafter Ngudjolo (Judgment, Concurring Opinion Judge Van den Wyngaert)).

95  See also The Prosecutor v Lubanga (Judgment Pursuant to Article 74 of the Statute, Separate Opinion of Judge Fulford) ICC-01/04–01/06, (14 March 2012) paras 12, 13, 16 (Trial Chamber I) (hereafter Lubanga (Judgment, Separate Opinion of Judge Fulford)) (adopting a plain reading of the Statute).

96  Ngudjolo (Judgment, Concurring Opinion Judge Van den Wyngaert) (n 93) paras 14–20. See also Lubanga (Judgment, Separate Opinion of Judge Fulford) (n 94) paras 10–12.

97  George P Fletcher, ‘New Court, Old Dogmatik’ (2011) 9 J of Intl Crim Justice 179.

98  ibid 184.

99  See George P Fletcher, ‘Two Modes of Legal Thought’ (1981) 90 Yale L J 970, 988.

100  ibid 988–94 (on Germany); John Henry Merryman, ‘The Italian Style I: Doctrine’ (1965) 18 (2) Stanford L Rev 39, 42–3 (on Italy). See also William Twining and others, ‘The Role of Academics in the Legal System’ in Peter Cane and Mark Tushnet (eds), The Oxford Handbook of Legal Studies (OUP 2003) 920, 937 (hereafter Twinning and others, ‘The Role of Academics’).

101  Swiss Civil Code of 10 December 1907, art 1.3 (English translation available at <https://www.admin.ch/opc/en/classified-compilation/19070042/201604010000/210.pdf> accessed 3 July 2018.)

102  Twinning and others, ‘The Role of Academics’ (n 99) 936–37.

103  ibid 938. See also R C Van Caenegem, Judges, Legislators, and Professors (CUP 1987) 59–70.

104  Twinning and others, ‘The Role of Academics’ (n 99) 938; Andras Jakab, ‘Seven Role Models of Legal Scholars’ (2011) 12 German L J 757, 758–59.

105  Twinning and others, ‘The Role of Academics’ (n 99) 938–39; Jurij Fedynskyj, ‘Book Review: The Role of Judicial Decisions and Doctrine in Civil Law and Mixed Jurisdictions, edited by Joseph Dainow’ (1975) 50 Indiana L J 636, 637–38.

106  Claus Kreß, ‘Towards a Truly Invisible College of International Criminal Lawyers’ (2014) Torkel Opsahl, FICHL Occasional Papers Serie No 4, at 6.

107  ibid 6–7.

108  ibid 7–8.

109  ibid 26–33.

110  ibid 19. It bears mentioning that Kreß himself played a significant role in the codification of the crime of aggression.

111  See Mikkel Jarle Christensen, ‘Academics for International Criminal Justice: The Role of Legal Scholars in Creating and Sustaining a Legal Field’ (2014) iCourts Working Paper Series No 14 <https://papers.ssrn.com/sol3/papers.cfm?abstract_id=2539048> accessed 3 July 2018.

112  ibid 10–18 (tracing the career trajectories of some prominent lawyer-academics throughout the history of international criminal law). See also Sergey Vasiliev, ‘On Trajectories and Destinations of International Criminal Law Scholarship’ (2015) 28 Leiden J of Intl L 1, 9–10 (on the ever close connections between ‘academic scholarship’ and ‘scholarship of action’).

113  ibid 11–13. See also Carsten Stahn and Eric D Brabandere, ‘The Future of International Legal Scholarship: Some Thoughts on “Practice”, “Growth”, and “Dissemination” ’ (2014) 27 Leiden J of Intl L 1, 3–5.

114  Peil, ‘Scholarly Writings’ (n 12) 155–57 citing Fisheries (United Kingdom v Norway), Merits, Judgment, [1951] ICJ Rep 145, 148–49 (Individual Opinion of Judge Alvarez); Request for Interpretation of the Judgment of 15 June 1962 in the Case Concerning the Temple of Preah Vihear (Cambodia v Thailand), Provisional Measures, Order of 18 July 2011, Separate Opinion of Judge Trindade, [2011] ICJ Rep 566, Sections II–XI.

115  Antonio Cassese, ‘Introduction’ in Antonio Cassese (ed), Realizing Utopia: The Future of International Law (OUP 2012) xvii; Antonio Cassese (ed), Five Masters of International Law: Conversations with R-J Dupuy, E Jiménez de Aréchaga, R. Jennings, L. Henkin and O. Schachter (Hart 2011) 255–59.

116  For an exposition of Cassese’s critical positivism, see Isabel Feichtner, ‘Realizing Utopia through the Practice of International Law’ (2012) 23 European J of Intl L 1143, 1149–51; Hernández, ‘Responsibility’ (n 33) 28–9.

117  Robert Cryer, ‘International Criminal Tribunals and Sources of International Law: Antonio Cassese’s Contribution to the Canon’ (2012) 10 J of Intl Crim Justice 1045, 1061.

118  ibid 1049.

119  See Cassandra Steer, ‘Non-State Actors in International Criminal Law’ in Jean d’ Aspremont, W Michael Reisman, and Math Noortmann (eds), Participants in the International Legal System: Multiple Perspectives on Non-State Actors in International Law (Routledge 2011) 295, 295–99.

120  Public international law scholars have widely differing views on the appropriateness of this normative function played by publicists. See generally Jörg Kammerhofer, ‘Orthodox Generalists and Political Activists in International Legal Scholarship’ in Matthew Happold (ed), International Law in a Multipolar World (Routledge 2011) 138, 146–47; Jochen von Bernstorff, ‘International Legal Scholarship as a Cooling Medium in International Law and Politics’ (2014) 25 European J of Intl L 977; Oppenheim, ‘Science of International Law’ (n 34) at 335; Schwarzenberger, ‘The Province of the Doctrine’ (n 23) 244, 259 (critical of this normative role).

121  However, as discussed earlier, these previous decisions are themselves based on the teachings of publicists, which remain the original source for the modes of liability.

122  See e.g., Situation in the Republic of Kenya (Decision Pursuant to Article 15 of the Rome Statute on the Authorization of an Investigation into the Situation in the Republic of Kenya) ICC-01/09-19-Corr, (31 March 2010) fns 83–85, 87–90 (Pre-Trial Chamber II) (on the meaning of a state or organizational policy to commit an attack); The Prosecutor v Ruto and Sang (Decision on Defence Applications for Judgments of Acquittal, Dissenting Opinion of Judge Herrera Carbuccia) ICC-01/09–01/11, (5 April 2016) fns 70, 72, 73, 75, 76, 78, 79, 80, 82, 83, 85, 87, 88, 90, 92 (Trial Chamber V(A)).

123  Rome Statute (n 8) art 22.

124  See e.g., Jean d’ Aspremont, ‘The Idea of “Rules” in the Sources of International Law’ (2014) 84 British YB of Intl L 103 (hereafter d’Aspremont, ‘The Idea of “Rules” ’); Charlesworth, ‘Law-Making and Sources’ (n 31) 200. See also Jean d’Aspremont, ‘The Politics of Deformalization in International Law’ (2011) 3 Göttingen J of Intl L 503, 518–20 (describing various non-formalist approaches to sources of international law).

125  In Hartian terms, every legal system must have an ultimate single rule of recognition. See Grant Lamond, ‘Legal Sources, the Rule of Recognition, and Customary Law’ (2014) 59 American J of Jurisprudence 25, 28.

126  d’Aspremont, ‘The Idea of “Rules” ’ (n 123) 115–17.

127  See e.g., Neha Jain, ‘Interpretive Divergence’ (2017) 57 Virginia J of Intl L 45 (analyzing the ICC’s approach to treaty interpretation).