In a recent development, with profound implications for positive complementarity, the OTP of the ICC entered into a Cooperation Agreement [Cooperation Agreement between the Office of the Prosecutor of the International Criminal Court and the Government of Colombia, signed in the city of Bogota, D.C., on October 28, 2021 202111028-OTP-COL-Coperation-Agreement, available online.] with the Government of Colombia, on October 28, 2021, which was “inspired by the principle of complementarity.” [See Office of the Prosecutor Press Release (Oct. 28, 2021) The Office of the Prosecutor of ICC, Mr. Karim Khan KC, concludes preliminary examination of the Situation in Colombia with a Cooperation Agreement with the Government charting the next stage in support of domestic efforts to advance transitional justice, available online.] In its Statement, the OTP declared that the Agreement “marks the beginning of a new chapter of support and engagement—an example of positive complementarity in action.” [This is in consonance with position take by the Prosecutor, Karim Khan.] Notably, the agreement was designed to reinforce and further define the mutual roles of the parties to ensure significant progress is achieved by domestic prosecutorial and judicial entities of Colombia [See Lievano AB, The ICC backs Colombia’s Transitional Justice Model, JusticeInfo (Nov. 9, 2021), available online.] The OTP commits itself to engage in supporting and learning from national accountability processes in Colombia. [Cooperation Agreement, preamble, ¶ 14.] This Agreement has, arguably, breathed a new life into positive complementarity. [See generally Kai Ambos, The Return of “Positive Complementarity”, Blog of the European Journal of International Law (Nov. 3, 2021), available online.] It demonstrates the apparent realization by the Office of the Prosecutor that more needs to be done to cooperate with the national jurisdictions if the fight against impunity is to be effectively won. The engagement by the OTP with the national jurisdictions has thus become priority policy issue for the ICC Prosecutor, Karim Khan.

It is the argument of this comment that the Cooperation Agreement has, no doubt, engendered a renewed impetus, that has invariably provoked the intellectual desire, among many scholars and other stakeholders, and accentuated the need, to revisit the definition of positive complementarity. [See Rogier E, The Ethos of ‘Positive Complementarity,’ Blog of the European Journal of International Law (Dec. 11, 2018), available online. See also Bates G, The ICC Doesn’t Look So Interventionist After All, Foreign Policy, Dec. 8, 2021, available online] It is important to note that the definition of positive complementarity has never been settled. Various explanations have been advanced by different scholars, institutions, and other stakeholders as to what constitutes the policy or concept of positive complementarity. As we shall see later in this comment, some of the explanations advanced have tended to accentuate the conflation in the difference between the classical complementarity and positive complementarity.

In light of the preceding developments in the realm of international criminal justice, this comment seeks, in an overarching approach, to explore the development of the concept of positive complementarity, and to revisit its definition. [See Bernard, IJHSS 203 (2011).] It also explores the opportunities presented, the benefits generated, and the challenges posed by the development and implementation of the concept of positive complementarity. [See Salvatore, J. Int’l Crim. Just. 137 (2010).]

II. Positive Complementarity: A Concept in Intricate Relations

The Rome Statute does not provide any definition, let alone a mention, of the term “positive complementarity” or “complementarity”, other than the use of the term “complementary” in its preamble and in article 1. The Statute merely provides that the ICC shall be complementary to national criminal jurisdiction. [Article 1 of the Rome Statute.] The origin of the term complementarity can be explained by the fact that it was coined by the delegates, during the drafting sessions of the Rome Conference, [See United Nations Diplomatic Conference of Plenipotentiaries on the Establishment of an International Criminal Court Rome 15 June-17 July 1998 Official Records vol 1 Final Documents A/CONF.183/13 (vol I). The Final documents are available online.] to cover the admissibility requirements under article 17 of the Rome Statute. [See Crawford, Drafting of the Rome Statute 109, 147. See further Benedetti & Washburn Global Governance 22. See also Heller, Crim. Law Forum 257 (2006), available online.] It emerges that the provisions of the Rome Statute emphasize complementarity as one of the cornerstones of the functioning and jurisdiction of the ICC. [See Cooperation Agreement, ¶ 3.]

The principle of complementarity maintains that, in general, the national criminal courts will enjoy priority, over the ICC, in the investigation and prosecution of Rome Statute crimes committed within its national jurisdiction. [Author’s thesis.] Put another way, the ICC complements, rather than supersedes, the national jurisdiction. The ICC may only intervene in such cases when the national jurisdiction is “unable or unwilling” to effectively undertake its responsibilities. [Author’s thesis.] In light of the preceding explanation, complementarity may be viewed as a tool for the apportionment of jurisdiction between the national courts and the ICC. [See Bergsmo, Eur. J. Crime. Cr. J. 345 (1998).]

Complementarity, in essence, forms the basis upon which the concept of positive complementarity evolved. There is evidently an intricate linkage between the concept of positive complementarity and the classic principle of complementarity. It is worth noting that the ICC, in its jurisprudence, has not come up with any functional definition of the concept of positive complementarity. It may be asserted that, currently, there is no formal source of international criminal law that expresses the definition of positive complementarity. [See discussion in Thormundsson J, The Sources of International Criminal Law With Reference to the Human Rights Principles of Domestic Criminal Law, Stockholm Institute of Scandinavian Law, 387–93, available online.] Consequently, it may be argued that positive complementarity is merely a concept devoid of formal legal content. [Nieto-Navia R, International peremptory norms (jus cogens) and international humanitarian law, available online further discussion on the normative value see Byers, Nord. J. Int’l L 213 (1997).]

However, positive complementarity may be defined in terms of the approach adopted by the first ICC Chief Prosecutor and the OTP which encourages genuine national proceedings where possible; relies on national and international networks; and participates in a system of international cooperation. [Office of the Prosecutor, Report on 14 September 2006, available online. See also, on the failure of state cooperation, Coalition for the International Criminal Court, State Cooperation: The Weak Link of the ICC, available online.]

From the preceding definition, it can be argued that positive complementarity connotes national and international networks in the pursuit of international criminal justice. The concept of positive complementarity has also been defined by the OTP as “a proactive policy of cooperation aimed at promoting national proceedings.” [Office of Prosecutor, Report on Prosecutorial Strategy 1 February 2010, available online.] It was defined as all activities or actions whereby national jurisdictions are strengthened and enabled to conduct genuine national investigations and trials of crimes included in the Rome Statute, without involving the Court in capacity building, financial support and technical assistance. [See Review Conference of the Rome Statute Draft Resolution on Complementarity ICC-ASP/8/Res.9 Annex VII (Jun. 8, 2010).]

The question to pose, at this juncture, is whether there is any correlation between the “impunity gap” [See discussion in Tladi D, Complementarity and cooperation in international criminal justice: Assessing initiatives to fill the impunity gap, Institute of Security Studies Paper (Nov. 27, 2014).] notion and the development of the concept of positive complementarity. This is examined in the ensuing section.

III. The Notion of “Impunity Gap” and Positive Complementarity

Where, owing to capacity constraints, the ICC prosecutes only those most responsible for international crimes, an “impunity gap” is created, thereby allowing lesser-ranking offenders a degree of impunity. [See Report of the Bureau on Stocktaking of the Principle of Complementarity: Bridging the Impunity Gap ICC-ASP/8/51 Resumed Eighth Session (Mar. 18, 2010).] Consequently, many lesser-ranking offenders are left for the domestic criminal courts to deal with. [See, for example, The Prosecutor v. Joseph Kony, Vincent Otti, Okot Odhiambo and Dominic Ongwen, ICC-02/04-01/05-377 (Mar. 10, 2009), available online.] Coupled with the limitations inherent in national jurisdiction, the result is that the “impunity gap” tends to remain largely addressed. Arguably, this has led the ICC, in some instances, to cooperate with national jurisdictions to ensure that all the perpetrators of atrocity crimes are brought to justice. It has been argued that, in this way, positive complementarity can help deal with the impunity gap by encouraging domestic prosecutions of Rome Statute crimes, even those that may not satisfy the “gravity threshold” for prosecution by the ICC. [See generally Burke-White, Harv. Int’l L. J. 49 (2014), available online]

The paper, therefore, underscores the significance of the concept of positive complementarity in addressing the shortcomings arising from the impunity gap. [See generally Bjork & Goebertus, Complementarity in Action, Yale Hum. Rts. & Dev. L. J. 205 (2014).]

IV. The Nature and Scope of Positive Complementarity

The principal tenets—most notably the definition, the constitutive elements, and the scope—of the concept of positive complementarity, remain largely unclear. The parameters of application, and the formal justification, for positive complementarity, have remained ambiguous, thereby rendering the concept susceptible to varied interpretations. The absence of a universally acceptable definition introduces a degree of uncertainty as to the exact nature of positive complementarity. This renders it a mere instrument of rhetoric rather than an effective instrument for sealing the impunity gap. Attempts by various scholars to refine the basic tenets of positive complementarity do not appear to have settled this issue. [See generally Stahn, J. Int’l Crim. Just. 695 (2005); Stahn, El Zeidy & Olásolo, Am. J. Int’l L. 421 (2005); Stahn, Leiden J. Int’l Law 311 (2010); Stahn, Crim. Law Forum 87 (2008).]

V. The Informal Expert Report

The limited resources available to the ICC have prevented the Court from achieving the lofty objectives of international criminal justice, [See Damaska, JILFA 19, 32 (2009).] and have, in part, influenced the OTP to reconsider the prosecutorial strategies it adopted with regard to its role within the Court structure. [See Danner, Am. J. Int’l L. 510, 543 (2002).]

The policies of the OTP as regards complementarity were partly influenced by the 2003 Informal Experts Report [Office of the Prosecutor, Informal Expert Paper: The Principle of Complementarity in Practice, ICC-OTP (2003) at 2, available online.] containing opinion on positive complementarity. [The Informal Expert Paper described “positive” complementarity as a policy concept.] Instructively, the Report observed that the OTP will initiate prosecutions of the leaders who bear most responsibility for the crimes. On the other hand it will encourage national prosecutions, where possible, for the lower-ranking perpetrators, or work with the international community to ensure that the offenders are brought to justice by some other means [See generally, Paper on Some Policy Issues Before the Office of the Prosecutor (Sep. 2003), available online.]

Thus the Report noted that complementarity is not intended to generate competition between the OTP and the domestic courts, but rather to encourage and support the domestic authorities to exercise national jurisdiction. It therefore suggests that the OTP should enter into a positive and constructive relationship with a state that is genuinely investigating and/or prosecuting an international crime. [See generally Office of the Prosecutor, Informal Expert Paper: The Principle of Complementarity in Practice, 11–12 (2003), available online.] The Report further proposes that under the legal mandate provided by the Rome Statute, the prosecutor can encourage the state concerned to initiate national proceedings, help develop cooperative anti-impunity strategies, and possibly provide certain forms of assistance to facilitate national efforts. [See discussion in Osofsky, 107 Yale L. J. 191 (1997).] The Report argues that it is within the mandate of the ICC prosecutor to exchange information and evidence to facilitate national investigations. [This argument is anchored in article 93(10) of the Rome Statute.] In effect, the Report states that by virtue of article 93(10), the Court may cooperate with and provide assistance to a state.

Assistance may be extended by way of technical advice, such as legal advice and other technical forms of intervention, to the authorities in the state [See Cakmak, IJWP 3 (2006).] to support its domestic courts in building capacity. [See Howland, Wis. Int. Law J. 419–20 (2000).] The advice extended to such states would include, for instance, practical skills and knowhow as regards investigations and prosecution, [See article 18 Rome Statute. See also views in Wierda M, Stocktaking: Complementarity, International Centre for Transitional Justice Briefing Paper (May 2010).] such as advice on evidence, forensic audits, and other substantive and procedural legal aspects of trials before the ICC. [See the UN, Report of the International Commission of Inquiry on Darfur to the United Nations Secretary-General Pursuant to Security Council Resolution 1564 of 18 September 2004 (Jan. 25, 2005), available online.] The training exercise would be geared towards helping build domestic capacity in how to address the exercise of jurisdiction effectively. [See Palmer, African Journal of International & Comparative Law 13–14 (2012).]

The Informal Expert Report further suggested vigilance on the part of the ICC, to constantly seek to establish whether national jurisdiction is being exercised in consonance with the requirements of the Rome Statute. [See article 17 of the Rome Statute. See also Philips, Crim. Law Forum 61 (1999).]

The drafters of the Report considered the elements of article 17 as the basis on which they built their proposals for positive complementarity. The power to conduct fact-finding exercises and to secure cooperation in the context of positive complementarity, was also addressed. In this regard, from the Report it appears that the cooperation regime under Part 9 of the Rome Statute is linked to an “investigation” as set out under article 86 of the Rome Statute and also to the powers of the prosecutor under article 54. This cooperation regime is relevant for positive complementarity from the point of view that states would cooperate to allow the ICC to contribute to their national efforts to fight impunity.

In the following section, the OTP’s understanding of and response to the Report is addressed.

VI. A “Positive Approach to Complementarity” by the Office of the Prosecutor

A. Introduction

As the ICC embarked on handling its first investigations, situations, and cases, it soon emerged that the lofty goals and expectations associated with its formation would be difficult to achieve. [See generally Burke-White Crim. Law Forum 59 (2008).] There was manifest misalignment between the lofty expectations of the international community and the reality of the constraints on resources available to the Court. [See generally Burke-White, Crim. Law Forum 59 (2008).] This situation provided the impetus for a need to re-evaluate the strategies to be adopted by the OTP in its role within the international criminal justice system. Accordingly, the OTP adopted what it termed “a positive approach to complementarity.” This approach was embodied in the policies in its various prosecutorial strategies. The OTP interpreted its legal mandate to extend beyond a reactive response to state failure, and it consequently undertook to be proactive in encouraging states and cooperating with national and international actors to ensure genuine accountability for serious crimes. [Office of the Prosecutor, Paper on Some Policy Issues Before the Office of the Prosecutor (Sep. 2003), available online.]

B. The 2003 Paper on Some Policy Issues before the Office of the Prosecutor

The OTP’s 2003 Paper on Some Policy Issues (2003 OTP Policy Paper) highlights an attempt at articulating an approach to complementarity that led to the emergence of an idea of positive complementarity. [See Alai, Measured Hope: Positive Complementarity and Accountability for Sexual Violence Crimes in Kenya, in International Criminal Justice: The International Criminal Court and Complementarity: International Commission of Jurists Kenya Section Paper, 58 (2014).] It recognizes that national investigations and prosecutions, where they can properly be undertaken, will normally be the most effective and efficient means of bringing offenders to justice. The 2003 Policy Paper embraced positive complementarity, and stated that the new concept creates space for the positive involvement of the OTP in technical assistance to national jurisdictions. [See Burke-White, Harv. Int’l L. J. 53 (2008).] The first Chief Prosecutor of the ICC, Luis Moreno Ocampo stated that the effectiveness of the International Criminal Court should not be measured only by the number of cases that reach the Court. On the contrary, the absence of trials by the International Criminal Court, as a consequence of the regular functioning of national systems, would be a major success. [See Report of the Prosecutor of the International Criminal Court, Mr. Luis Moreno-Ocampo, Second Assembly of States Parties to the Rome Statute of the International Criminal Court September 8, 2003, available online (last visited Sep. 23, 2023).]

Another critical policy issue brought to the fore by the policy document is that of the “impunity gap.” [See Report of the Prosecutor of the International Criminal Court, Mr. Luis Moreno-Ocampo, Second Assembly of States Parties to the Rome Statute of the International Criminal Court (Sep. 8, 2003), available online.] This is, arguably, an important element in determining the parameters of the concept of positive complementarity. [See Bergsmo, Bekou & Jones, GoJIL 794 (2010), available online.] Based on the limitations in its budget and personnel, the ICC prosecutes those who bear the greatest responsibility for the crimes committed and leaves lower-ranking perpetrators to be tried by their national courts. [Assembly of States Parties, Report of the Bureau on Stocktaking: Complementarity. Taking stock of the principle of complementarity: Bridging the impunity gap, ICC-ASP/8/51 Resumed Eighth Session (Mar. 18, 2010).] The ICC, therefore, put in place measures to encourage national courts and provide support where possible so the lesser offenders may not escape justice under domestic jurisdiction. [See Benzing, UNYB (2003).]

The OTP indicated that it would be “… encouraging States to carry out their primary responsibility of investigating and prosecuting crimes.” [See generally Policies and Strategies, ICC OTP available online (last visited Sep. 23, 2023).] The 2003 Policy Paper therefore set the foundation upon which the thinking for positive complementarity begins to emerge. The ensuing prosecution strategy paper, discussed in the next section, takes this thinking a step further.

C. The Office of the Prosecutor: Prosecutorial Strategy 2006–2009

The 2006–2009 Prosecutorial Strategy Paper (2006–2009 Strategy). [Office of the Prosecutor, Report on 14 September 2006, available online.] sets out five strategic objectives of the OTP between 2006 and 2009. The fifth objective is most closely linked to positive complementarity, [The fifth strategic objective provides: “(e) to establish forms of cooperation with states and organizations to maximize the Office’s contribution to the fight against impunity and the prevention of crimes.”] as it provides that the Court will establish forms of cooperation with states and organizations to maximize the OTP’s contribution to the fight against impunity and the prevention of crime. [See Payam, Am. J. Int’l L. 403, 413 (2005).] It is submitted that this cooperation is an essential element of positive complementarity.

In its 2006–2009 Strategy, the OTP underscored the important role states play in the realisation of the goals of the concept of positive complementarity by “…emphasizing that according to the Statute national states have the primary responsibility for preventing and punishing atrocities in their own territories.” [See Hall, Positive Complementarity in Action, 1017.] The OTP officially pronounced “A positive approach to complementarity” [Office of the Prosecutor, Report on Prosecutorial Strategy, 3 (Sep. 14, 2006), available online (last visited Jun. 6, 2022). See also Ocampo LM, A Positive Approach to Complementarity, 23.] in which it declared that the OTP encourages genuine national proceedings where possible; relies on national and international networks; and participates in a system of international cooperation. [Gioia, Reverse Cooperation 75. See also on the failure of state cooperation, Coalition for the International Criminal Court, State Cooperation: The Weak Link of the ICC, available online.]

The OTP thus pursued a policy of encouraging genuine national proceedings where possible, including in situation countries, relying on its various networks of cooperation but without involving the Office directly in capacity building or financial or technical assistance. [See generally Gallmetzer, J. Int’l Crim. Just. 952, 956 (2010).] The prosecutor, therefore, construed his legal mandate to include a mutually reinforcing system of international criminal justice in which both the domestic and international jurisdictions were interdependent and acted as partners in limiting impunity. [Ocampo, A Positive Approach to Complementarity, 23.] It was during this period that the Court issued the Regulations defining the main policies of the OTP governing, inter alia, positive complementarity. [See Office of the Prosecutor, Report on Prosecutorial Strategy (Sep. 14, 2006), available online (last visited Jun. 6, 2022). See also, Burke-White, Reframing Positive Complementarity, 341.]

D. The Office of the Prosecutor’s Prosecutorial Strategy 2009–2012

The OTP’s Prosecutorial Strategy Policy Paper 2009–2012 (2009–2012 Strategy) [See Office of Prosecutor, Report on Prosecutorial Strategy (Feb. 1, 2010), available online.] emphasizes the significance of cooperation between the ICC and various actors and stakeholders in the international criminal justice system. [Office of Prosecutor, Report on Prosecutorial Strategy (Feb. 1, 2010), available online (last visited Jun. 13, 2022).] The OTP undertakes, in the report, to work with states and international, regional, thematic, and judicial organizations to, inter alia, promote national activities including the adoption of implementing legislation and the promotion of domestic proceedings. [Office of the Prosecutor, Report on Prosecutorial Strategy 2009–2012, ¶ 7, available online (last visited Jun. 24, 2022).] This is important to our analysis as it serves as a pointer to one of the characteristics of the concept of positive complementarity, namely, cooperation. [See Cassese, The Rationale for International Criminal Justice 1664.]

In the 2009–2012 Strategy, the OTP attempted to distinguish the two forms of complementarity by stating that:

[T]his principle of complementarity has two dimensions: (i) the admissibility test, i.e. how to assess the exercise of national proceedings and their genuineness, which is a judicial issue; and (ii) the positive complementarity concept, i.e. a proactive policy of cooperation aimed at promoting national proceedings. [Office of Prosecutor, Report on Prosecutorial Strategy (Feb. 1, 2010), available online ¶¶ 8, 16]

Under the positive complementarity scenario, the Court should provide support to domestic initiatives by helping to build national capacity. [See Takemura, A Critical Analysis of Positive Complementarity, 601, available online.]

The 2009–2012 Strategy of the OTP sought to reinforce efforts by domestic courts to combat impunity within the framework of the international criminal justice system. What is incontestable is that the ICC has tended to adopt a more cooperative strategy in which various stakeholders are actively engaged in tackling the challenges raised by the fight against impunity. [See generally Kleffner, J. Int’l Crim. Just. 86 (2003).]

VII. A Normative Challenge in the Definition of Positive Complementarity

Any attempt at a definition of the concept of positive complementarity will of necessity raise normative questions. The concept does not answer to definitive elements, legal parameters, or scope that would enable us to define it with exactitude. Its normative character remains elusive but the paper seeks to pin down key characteristics of the concept. [See generally Cross & William, Hum. Rights Law Rev. 344 (2010); See also Takemura, A Critical Analysis of Positive Complementarity 601.] The normative justification for positive complementarity is the subject of considerable discourse in existing literature. [See Burke-White, Crim. Law Forum 59 (2008).]

The concept of positive complementarity is the idea that the ICC and, notably, the prosecutor and the OTP, should work to engage national criminal courts in prosecutions, using various methods to encourage states to prosecute international criminal cases domestically whenever possible. [See Gioia, Reverse Cooperation, 75.]

It is submitted that the ultimate goal of a policy of positive complementarity is to strengthen the capacity of national criminal courts. This arguably will, in turn, have a significant positive impact on the promotion and restoration of the rule of law and thus the prevention of future atrocities. [See Burke-White, Harv. Int’l L. J. 53 (2008).] In retrospect, it has already been noted that this policy is geared towards enhancing concerted international efforts at limiting impunity. [See Stahn, Crim. Law Forum 87 (2008).]

It has been argued that positive complementarity is not expressly regulated, but it is embedded in the structure of complementarity in the Rome Statute. [See generally Burke-White, Harv. Int’l L. J. 49 (2008).] This does not, however, appear to provide a more succinct explanation of the term positive complementarity.

A. The Normative Discourse on “Positive” Complementarity

Stahn states that complementarity has been claimed to have many faces and has raised a paradox. [See generally Stahn, Taking Complementarity Seriously, 233.] He says that complementarity has traditionally been theorized on the basis of a distinction between “classical” and “positive” complementarity. [See generally Stahn, Taking Complementarity Seriously, 233.] The normative question posed is: To what extent does the classification of complementarity as “classical” or “positive” define the normative characterization of positive complementarity? It is submitted this classification will ultimately derive its validity from the contextual interpretation of the Rome Statute. [See arts 17 and 53 of the Rome Statute.]

According to Stahn, the jurisdiction of the ICC and the national authority may complement each other by interacting in a “positive” way, including engaging in activities that render mutual assistance. He argues that this “positive” dimension is not fully covered by the threat-based vision of complementarity. [See generally Stahn, Taking Complementarity Seriously, 233.]

Against this background, positive complementarity is viewed as a model that promotes a constructive relationship grounded on “partnership” and “dialogue” between the ICC and states, as opposed to the antagonistic approach inherent in the “classic” vision. [See generally Takemura, A Critical Analysis of Positive Complementarity, 601.] The positive approach to complementarity thus encourages genuine national proceedings where possible, particularly where the domestic courts are willing but perhaps unable to prosecute due to constraints such as inadequate capacity. [See generally Takemura, A Critical Analysis of Positive Complementarity, 601.]

In the preceding respect, positive complementarity is viewed more as a legal tool to strengthen international criminal jurisdiction by strengthening domestic jurisdiction. [This reflects the definition advanced in the Discussion Paper on Positive Complementarity presented by South Africa and Denmark, where the concept is defined it as “… describing all actions and activities aimed at supporting national jurisdictions in meeting their obligations under the Rome Statute, including related activities aimed at strengthening the rule of law.” See generally, Discussion Paper submitted by Denmark and South Africa, Bridging the Impunity Gap Through Positive Complementarity, 24 (Nov. 6, 2009). That definition proved to be so broad and was latter narrowed down in the Report of the Bureau on Stocktaking which defined positive complementarity as “all activities/actions whereby national jurisdictions are strengthened and enabled to conduct genuine national investigations and trails of crimes included in the Rome Statute, without involving the Court in capacity building, financial support and technical assistance.”]

Stahn also perceives positive complementarity as a “managerial” concept that is instrumental in organising the common responsibility of both national courts and the ICC by ensuring a division of labour and burden-sharing between the two entities.

The proposition by Stahn that positive complementarity is a managerial concept, is problematic from a normative point of view on two important levels. The first level is that the statement presupposes that legal instruments exist for ensuring effective management systems. Secondly, but flowing from the argument on the first level, is that it does not concern itself with an evaluation of the effectiveness of the so-called management system. Consequently, this only helps to generate confusion about what exactly positive complementarity as a managerial concept entails.

Burke-White, [See generally the series of works in which Burke-White attempted a spirited advocacy for proactive complementarity: Burke-White, Leiden J. Int’l Law 557 (2005); Burke-White, Harv. Int’l L. J. 53 (2008); Burke-White, Crim. Law Forum 59 (2008); and finally, Burke-White & Kaplan, J. Int’l Crim. Just. 257 (2009).] for his part, argues that “pro-active” complementarity is not expressly regulated but is embedded in the structure of complementarity in the Rome Statute. [See Burke-White, Harv. Int’l L. J. 49 (2008).] He argues for a change in the role of the ICC by practicing the policy of “proactive complementarity” by way of encouraging domestic courts to undertake national prosecutions. [See generally Burke-White, Harv. Int’l L. J. 53 (2008).] In effect, he advocates the shifting of the responsibility to prosecute offenders from the ICC to national courts. [See generally Burke-White, Harv. Int’l L. J. 59 (2008).] He further examines the legal mandate of the ICC to implement the policy of pro-active complementarity. [See generally Burke-White, Harv. Int’l L. J. 59 (2008).] To this extent he attempts to develop a normative justification for “proactive complementarity”. He argues that pro-active complementarity better reflects the nature of the policy and can be distinguished from “passive complementarity” which, according to him, is the approach the ICC has taken. [See generally Payam, Am. J. Int’l L. 403, 413 (2005).] His arguments are extremely significant in the context of the current debate.

Some may as well argue that the proposition adopted by Burke-White is a reflection of the OTP’s vision of positive complementarity. [See Robinson, Crim. Law Forum 67 (2010); Perrin, Sri Lanka JIL 301 (2006).] But caution ought to be exercised with that line of argument as it loses track of the critical elements Burke-White raises to justify the use of the term “proactive” as opposed to “positive”. Some of these elements could simply be summarized as normative constituents of proactive complementarity.

Based on the preceding analysis, it could be argued that positive complementarity and classical complementarity are founded on different premises. However, the arguments advanced by Nouwen regarding the plausibility or otherwise of the concept of positive complementarity are very interesting. She appears to take a radically different approach to whether positive complementarity can indeed stand as a term. [See Nouwen Complementarity in the Line of Fire 11.] Nouwen argues that complementarity has been living a double life: on the one hand, from a legal point of view it is a technical admissibility rule provided for in the Rome Statute and governing how the ICC may proceed with the investigation or prosecution of a case within its jurisdiction; [See Nouwen Complementarity in the Line of Fire 11.] on the other hand, complementarity presents as a “big idea” resulting from the work of writers, diplomats, activists, and legal practitioners. [See Nouwen Complementarity in the Line of Fire 11.]

To begin with, Nouwen’s argument, above, does not dismiss complementarity as a “big idea” stemming merely from the arguments of a certain class of people, but recognizes that although it bears little resemblance to the admissibility rule, complementarity as a “big idea” includes “responsibilities” and even obligations for states. [Compare with the arguments in Kaplan, J. Int’l Crim. Just. 257 (2009).] She contends that the advocates for complementarity as “a big idea” seek to promote a normative agenda beyond the confines of the Rome Statute. [In light of Nouwen’s argument it is instructive to look at Gioia, Reverse Cooperation, 75.]

The arguments above, by Nouwen, raise a normative challenge. Firstly, these lines of argument create considerable difficulty in ascertaining the justification for the policy concept in terms of which Nouwen identifies complementarity as the “big idea”. Secondly, they introduce confusion in that they fail actually to establish the normative existence of complementarity as “a big idea”.

It is, moreover, argued that the reference to “complementarity” as the policy of positive complementarity, is misleading, and that in effect the policy comes down to a form of cooperation which requires the ICC to facilitate domestic proceedings rather than the states assisting in the proceedings of the Court. [See Nouwen, Complementarity in the Line of Fire 97.]

It has been argued that a policy of assisting domestic jurisdiction is not inherent in complementarity. On this reasoning, it is not surprising that Nouwen elects to use the term complementarity as a “big idea” [Nouwen prefers the use of the term “complementarity” as a “big idea” in her works, electing to stay clear of the use of positive complementarity, and discussing it as a misnomer.] rather than positive complementarity.

Positive complementarity has not yet received juridical endorsement from the ICC judges [In all matters in which the Court has made a determination there has so far been no definition of positive complementarity advanced by any of the judges.] which continues to make the exact normative value and application of the concept uncertain.

The normative difficulty introduced by the foregoing frame of argument is that it presupposes a static or rigid supply of resources to the Court. The argument would have been more problematic had it operated on the assumption that national jurisdictions would naturally be cooperative. This assumption, however, fails plausibly to account for the possibility that national courts may refuse to cooperate with the ICC. In the absence of cooperation Nouwen’s argument collapses.

It is submitted that Stahn’s classification and his distinction between classic and positive complementarity provide fairly justifiable grounds for the establishment of the concept of positive complementarity—the positive form is a departure from the jurisdictional rigidity that has characterized classic complementarity. [Stahn, Crim. Law Forum 87 (2008). See also Stahn, Taking Complementarity Seriously, 233.]

It is necessary to exercise caution in the use of the word “positive” as it opens a “Pandora’s box” leading to normative ambiguity. The absence of a universally acceptable definition of the concept of positive complementarity has the potential to create ambiguity. It thus creates confusion when one uses the terms “proactive”, “positive” or “negative” complementarity. This raises a need to clarify the normative features of complementarity in general and positive complementarity in particular.

To summarise: the concept of positive complementarity still attracts differing perspectives and interpretations. There is no settled definition from the existing literature analyzed. There appears to be a multi-faceted approach to explaining what the concept of positive complementary means. In all these arguments, however, it emerges that positive complementarity is a radical departure from the basic elements of classic complementarity.

B. The Jurisprudential Foundation of Positive Complementarity

There is a glaring dearth of jurisprudence on positive complementarity. Interestingly, in The Prosecutor v. Saif Al-Islam Gaddafi and Abdullah Al-Senussi, [See generally The Prosecutor v. Saif Al-Islam Gaddafi and Abdullah Al-Senussi, ICC-01-/11-01/11 (2013).] the Libyan government’s legal team argued that:

Libya invites the Court to embrace the concept of positive complementarity in a manner which gives full effect to the object and purpose of the Statute and the spirit of complementarity by allowing the Libyan Government time to complete its domestic proceedings relating to Abdullah Al-Senussi subject to monitoring and the acceptance of assistance or fulfilment of other express initiatives and obligations. [The Prosecutor v. Saif Al-Islam Gaddafi and Abdullah Al-Senussi, ICC-01-/11-01/11, 90 (2013).]

The submission continued:

[T]his case provides a unique opportunity to embrace the concept of positive complementarity in a manner which gives full effect to the object and purpose of the Statute and the spirit of complementarity by allowing the Libyan Government time to complete its domestic proceedings relating to Abdullah Al-Senussi subject to monitoring and the acceptance of assistance or the fulfilment of other express initiatives and obligations. [The Prosecutor v. Saif Al-Islam Gaddafi and Abdullah Al-Senussi, ICC-01-/11-01/11, 91 (2013).]

The concept of positive complementarity engenders new normative considerations which have not yet found a settled common ground among scholars and practitioners of international criminal law. This argument is echoed in the further submission by the Libyan-government team that:

There is no explicit reference to this concept [of positive complementarity] in the Statute, nor was it canvassed during the negotiations on complementarity, which instead focussed on developing acceptable ways to regulate jurisdictional disputes between the International Criminal Court and active national jurisdictions. [See The Prosecutor v. Said Al-Islam Gaddafi and Abdullah Al-Senussi, ICC-01/11-01/11-1 (PTC I, Jun. 27, 2011).]

The submission continues further that:

However, the Statute foreshadows the formal implementation of positive complementarity initiatives by reason of its powers to regulate the admissibility proceedings as it deems appropriate pursuant to rule 58(2), providing that this does not occasion “undue delay” [The Prosecutor v. Said Al-Islam Gaddafi and Abdullah Al-Senussi, ICC-01/11-01/11-1 (PTC I, Jun. 27, 2011).]

It is, moreover, argued that “the formal implementation of positive complementarity initiatives would enhance the certainty of any final disposition of the Article 19 challenge.” [The Prosecutor v. Said Al-Islam Gaddafi and Abdullah Al-Senussi, ICC-01/11-01/11-1 (PTC I, Jun. 27, 2011).] By ensuring the implementation of positive complementarity initiatives, the elements would be settled and that would provide the courts with a predictable basis for adjudication on matters involving the concept and, more particularly, admissibility issues under article 19. What is indeed surprising is that in response to the application by the government of Libya which articulated the concept of positive complementarity, Counsel for Al-Senussi made no mention of positive complementarity, as if to suggest it unworthy of attention.

It is instructive to note that in rendering its decision declaring the case inadmissible, Pre-Trial Chamber I did not cite positive complementarity as a ground for its decision but rather arrived at its decision based strictly on the admissibility rules as set out in article 17. However, it is argued that the submissions by the Government of Libya presented very forceful arguments for the implementation of positive complementarity.

The preceding submissions underscore the need for a coherent legal and institutional framework for the implementation of positive complementarity. What further emerges is that the normative identity of positive complementarity remains largely elusive.

VIII. The Rome Statute and Positive Complementarity

Does positive complementarity derive its validity from the Rome Statute? This is the question addressed in this section. It is argued that certain core legal features can be ascribed to the concept of positive complementarity and are rooted partly in the classic complementarity regime and partly in the provisions of the Rome Statute. [See Stahn, Taking Complementarity Seriously, 233.]

In this context, positive complementarity is distinct from the “classic” concept of complementarity which is the admissibility principle embedded in article 17 of the Rome Statute. In essence, it has been argued that the development of the concept of positive complementarity is largely the result of a liberal interpretation of the Statute by the ICC prosecutor. [See generally Hewett, Yale J. Int’l L. 276 (2006).]

Nothing in the Rome Statute expressly regulates positive complementarity. However, articles 17, 53, 54(1)(b) and 93(10) of the Statute are instructive in establishing to what degree positive complementarity is actually provided for in the Rome Statute. Paragraphs 4, 6 and 10 of the Preamble to the Rome Statute are equally important in providing a legal basis for positive complementarity in the Rome Statute. The essence of these provisions is to improve effective prosecution and international cooperation, with the overall objective of effectively combating impunity.

One critical assertion by Stahn which invites analysis is that “positive complementarity” is not only a policy invention, but an inherent concept in the Statute. [See Stahn, Leiden J. Int’l Law 311 (2010).] This argument effectively challenges the view that “positive” complementarity is based exclusively on the desire to ensure the empowerment of domestic jurisdiction. [The Prosecutor v. Said Al-Islam Gaddafi and Abdullah Al-Senussi, ICC-01/11-01/11-1 (PTC I, Jun. 27, 2011).] But Stahn goes on to caution that complementarity is nonetheless under-theorized in the Rome Statute. From this argument one may infer that certain provisions in the Rome Statute specifically provide for a positive complementarity regime. [Article 17 of the Rome Statute.]

Both classic and positive complementarity ultimately derive their legitimacy from the Rome Statute. Further, the inadequate articulation and meaning of both concepts has been laid at the door of the drafters of article 17 of the Statute. [See Nouwen, Complementarity in the Line of Fire, 11. See further Burke-White, Crim. Law Forum 59 (2008).] It has been argued that classic complementarity, which flows from the Rome Statute, is grounded on a vertical model defining the relationship between the ICC and national courts. The argument further maintains that human behaviour is controlled by a well-managed system which invokes checks and balances to address shortcomings in the jurisdiction of national courts. [See El Zeidy, Mich. J. Int. Law 869 (2002).]

These propositions introduce arguments as to the hierarchical assumptions regarding a “vertical” relationship which implies that superior jurisdiction is conferred upon the ICC to oversee the inferior jurisdiction enjoyed by national courts. [See Perrin, Sri Lanka JIL 301 (2006).] This assumption is arguably consistent with the Rome Statute model. [Articles 17 and 53 of the Rome Statute.] It is submitted, however, that the checks-and-balances argument also lacks objectivity and is in fact equally subjective in that empirical justification is largely wanting. To this extent the “vertical features” argument is unconvincing. [See arguments in Stahn, J. Int’l Crim. Just. 695 (2005).]

It is only in certain instances that the Rome Statute empowers the prosecutor of the ICC to carry out certain actions that would be regarded as constituting positive complementarity. [See Danner, Am. J. Int’l L. 510, 543 (2002).]

Stahn argues that the critical element in the international system of justice grounded on the Rome Statute is the notion of “shared responsibility”. [Danner, Am. J. Int’l L. 510, 543 (2002).] Stahn argues that although the concept of shared responsibility was not expressly addressed by the drafters on the Statute, it is nonetheless reflected in different provisions in the Statute. [Danner, Am. J. Int’l L. 510, 543 (2002).]

Nouwen, who appears to advocate the use of the “big idea”, nonetheless analyses the Rome Statute in detail with regard to positive complementarity. [See Holmes, The Principle of Complementarity 41, 45. See also Nouwen, Complementarity in the Line of Fire 11.] She argues that the Statute explicitly provides the ICC prosecutor with powers only in some identified aspects of positive complementarity. [See Nouwen, Complementarity in the Line of Fire 98.]

Under article 15(2) of the Statute the OTP is empowered to seek additional information from a state when considering whether to open up investigations with a view of alerting a state of the looming prosecutions. [See Rodman, Leiden J. Int’l Law 96 (2009).] These actions by the OTP are understood to generate the “fear” or awareness in the state concerned that the OTP is determined to proceed, and arguably would serve as a catalyst for domestic investigation and prosecution in a bid to avoid intervention by the ICC. This could be termed a sovereignty-protectionist argument. [See Damaska, JILFA 19, 32 (2009).] It is, however, debatable whether such actions, in the ordinary course of events, would naturally lead to national action in terms of expedited investigations or prosecution. The argument must be examined in the light of article 18 of the Rome Statute which gives primacy to national courts as regards domestic investigations and prosecutions.

It is argued that the Rome Statute defines the interaction between the ICC and states through the mechanism of duties—as opposed to the rights and privileges in primacy of jurisdiction. [Stahn, Crim. Law Forum 87 (2008).] Stahn argues that neither the ICC nor the states enjoy primacy of jurisdiction per se. [Stahn, Crim. Law Forum 87 (2008).] In this respect they share concurrent jurisdiction or parallel responsibility founded on a division of duties. He then argues that the resulting system of international justice is structured and based on four key elements, namely, mutual cooperation; forum allocation; vertical and horizontal dialogue; and, finally, incentive-based compliance. [It should be noted that under the Rome Statute, unlike 1994 ILC Draft Model Statute, admissibility is no longer a discretionary principle, but a mandatory legal framework which determines the allocation of competencies and dispute settlement mechanism for establishing the proper exercise of jurisdiction by all stakeholders, including the Court, states, etc.] The normative dimension of the interaction between the state and the Court is less articulated and less developed in the context of the Rome Statute. [See generally Sedman, Prosecution of Ordinary Crimes, 259.]

The normative challenge in the above propositions is that they portray the ICC as an institution that propagates advocacy catalyzing the national criminal courts to take up their national responsibilities to investigate and prosecute. This poses serious normative difficulties for justifying positive complementarity. Normative difficulties, because, the very existence of the OTP and the ICC as a whole, is inspired by their complementary roles in pursuing investigations and prosecuting international crimes within well-defined judicial parameters under article 17 of the Statute.

To trigger such support from the Court, the state concerned must prompt the ICC by means of an express request for assistance as provided under the Statute. [See generally the discussion in Olasolo, Int. Crim. Law Rev. 121 (2005).] There is no basis in the Statute for the ICC to initiate the process of assistance. In a similar vein, it could be argued that nothing in the Statute prevents the Court from initiating assistance.

Accounts and propositions presented by some advocates of positive complementarity include much more than merely providing information and other forms of judicial assistance. The technical assistance and capacity building of the national state, in general, are all critical elements of the concept of positive complementarity but are not unequivocally covered under the Statute.

However, in the early years of the ICC the classic model proved to be rigid in that it did not afford the Court the flexibility to confront impunity by other viable means. This is seen in situations such as those that arose in Kenya, Darfur, and Colombia. However, this argument could be countered by asserting that the ICC is a creature of statute and, therefore, its operations must be confined within the mandate provided under the empowering Rome Statute.

IX. 2010 Kampala Review Conference on Stocktaking of the Rome Statute

Seven years after the Statute entered into force, the first Review Conference of the Rome Statute was finally convened from May 30, 2010 to June 11, 2010 in Kampala. The 2010 Kampala Review Conference (KRC) was engaged in a stocktaking exercise designed to assess and evaluate the successes and failures of the ICC during its first years of operation in light of the Rome Statute. [Clark, GoJIL 689 (2010).] The concept of positive complementarity, in particular, was debated [Clark, GoJIL 689 (2010).] at length before and during the plenary session of the KRC. The delegates raised an assortment of propositions and arguments around the status of positive complementarity. Complementarity was one of the four topics set for review at the KRC. South Africa and Denmark were the focal points for the review document that provided detailed discussion on positive complementarity.

The Report of the Bureau on Stocktaking emphasizes that the core mandate and function of the ICC is a judicial one and that it should not be mistaken for a development agency. [Clark, GoJIL 689 (2010).] The Report then addresses the improvement of the readiness of national states through positive complementarity. It notes that positive complementarity can take many forms. The Report states that positive complementarity refers to all the activities/actions whereby national jurisdictions are strengthened and enabled to conduct genuine national investigations and trials of crimes included in the Rome Statute without involving the International Criminal Court in capacity building, [See generally Proceedings of the Kampala Review Conference on the Rome Statute, by the Focal points (Denmark and South Africa) outlined examples of projects aimed at strengthening domestic jurisdictions to deal with article 5 crimes RC/ST/CM/INF.2 (May 30, 2010), available online] financial support and technical assistance, but instead leaving these actions and activities for States, to assist each other on a voluntary basis. [¶ 16 of the Report of the Bureau at Eighth Resumed Session.]

It further states that the actual assistance envisaged in the definition above, should be delivered through cooperative programs between states themselves, as well as through a network of international and regional organizations and civil society. [Report of the Bureau at Eighth Resumed Session, ¶ 17.]

In summary, the Report recommends steps that could be taken to advance the principle of complementarity through positive complementarity at the domestic level. The Bureau further recommended that a report on positive complementarity be compiled by the state parties and that this be presented to the ASP for further attention. Allied to the preceding point, the Bureau recommended that state parties consider further measures at national level in cooperation with the ICC—for example, other forms of assistance under the heading of positive complementarity. [Report of the Bureau at Eighth Resumed Session.] Further, apart from setting up a designated function within the Secretariat of the ASP, the Bureau and ASP should continue to engage with stakeholders in the international community on the most effective means of combating impunity at domestic level through positive complementarity.

It is instructive to note that certain states questioned the tenability of the definition of positive complementarity as presented by the Bureau on Stocktaking of the Rome Statute. Notwithstanding the apparent consensus on the use of the term positive complementarity throughout the review session, Germany and Spain interrogated the legal foundation of the concept. In effect, the normative relevance of the concept of positive complementarity was called into direct question. The perceivable facets of this concept were subjected to close scrutiny.

To highlight the apparent lack of consensus on the definition of the concept of positive complementarity, it is important to examine the positions adopted by different states. The Spanish delegation, for instance, interestingly, suggested that the set of initiatives or activities included under positive complementarity might as well be simply referred to as “technical assistance”. [See Bergsmo, Bekou & Jones, GoJIL 794 (2010), available online (last visited Jun. 20, 2022).] Similarly, the German representatives indicated, skeptically, that the term positive complementarity lacked legal basis within the context of the provisions of the Rome Statute, and that it only “served to confuse judicial capacity building with the principle of complementarity as laid down in Article 17 of the Rome Statute.” [Bergsmo, Bekou & Jones, GoJIL 794 (2010), available online (last visited Jun. 20, 2022).]

The two preceding arguments by Germany and Spain are indeed persuasive challenges to the justification of the concept of positive complementarity and reflect the depth of uncertainty surrounding the normative status of the concept.

In conclusion, significantly, the developments at the KRC witness not only renewed emphasis on positive complementarity, but also a shift in the application of the term “positive complementarity”. A significant achievement of the KRC was the adoption of a definition of positive complementarity. [See generally Review Conference of the Rome Statute Draft Resolution on Complementarity ICC-ASP/8/Res.9 Annex VII (Jun. 8, 2010).] However, one of the difficulties posed by this definition is that it is subject to broad interpretation—for example, where it refers to “all activities”. This generalization is problematic, as it complicates the precise conceptualization of the elements in the definition, with the result that definition lacks the exactitude which characterizes normative precision.

The definition of positive complementarity was adopted at the KRC without any new legal obligation being introduced or imposed. As a consequence, no legal or institutional framework was formulated in the resolution to back the definition up, nor was there any indication of doing so in the future. This created a normative gap which will have to be addressed in that it signals a normative challenge with regard to the enforceability of the concept.

Ultimately, one must ask whether the KRC in fact presented any conclusive normative justification for the concept of positive complementarity. It is argued that no such concrete conclusion was arrived at. The definition was characterized by loose ends that defy normative exactitude. The normative analysis of positive complementarity reveals that a legal framework is yet to be fully developed to allow for the establishment of an enforceable regime of positive complementarity.

Against this background, this comment undertakes an analysis of the appropriate legal and institutional framework for positive complementarity in the following section.

X. Institutional Framework for Positive Complementarity

The ASP Secretariat is currently responsible for the performance of functions and the administration of matters involving positive complementarity. There are a number of factors that, cumulatively, have had a negative impact on the effectiveness of the ASP Secretariat to coordinate and facilitate the activities associated with the implementation of positive complementarity. The limiting factors range from the legal and political, to the inherently structural. Firstly, there is clear limitation in terms of financial resources available to the Secretariat due to the limited budgetary allocation from the ASP. [The sources of funding for the ASP are restrictive,, as they emanate from the member states.] Secondly, the Secretariat lacks the financial independence required to fulfil its mandate. It must rely on the budget allocation of the ICC as approved by the ASP. [This allocation of funding is normally approved only when the ASP convenes and authorizes the expenditure.] Finally, and importantly, the Secretariat is not directly a creature of the Rome Statute but rather was established by a resolution of the ASP. [Resolution for the Establishment of the Secretariat of the Assembly of States Parties to the International Criminal Court, International Criminal Court-ASP/2/Res.3.]

XI. Conclusion

Any attempt at a definition of the concept of positive complementarity will of necessity raise normative questions. The concept of positive complementarity still attracts differing perspectives and interpretations. There is no settled definition from the exiting literature analyzed. There appears to be a multi-faceted approach to explaining what the concept of positive complementary means. In conclusion, the various works consulted fail to come up with a uniform interpretation of the concept of positive complementarity.

In light of the preceding findings and conclusions, this comment recommends that the current Permanent Secretariat of the ASP should be restructured to incorporate certain key features, including a dedicated office, to enhance focus on promoting and coordinating activities relating to positive complementarity.

List of Abbreviations

Am. J. Int’l L.

American Journal of International Law

ASP

Assembly of State Parties

Camb. Rev. Int.

Cambridge Review of International Affairs

Crim. L. Forum

Criminal Law Review

Eur. J. Crime. Cr. J.

European Journal of Crime, Criminal Law and Criminal Justice

GoJIL

Goettingen Journal of International Law

Harv. Int’l L. J.

Harvard International Law Journal

Hum. Rts. L. R.

Human Rights Law Review

ICC

International Criminal Court

Int’l Crim. L. Rev.

International Criminal Law Review

IJHSS

International Journal of Humanities and Social Science

IJWP

International Journal on World Peace

JILFA

Journal of International Law & Foreign Affairs

J. Int’l Crim. Just.

Journal of International Criminal Justice

Leiden J. Int’l L.

Leiden Journal of International Law

UNYB

Max Planck Yearbook of United Nations Law

Mich. J. Int’l L.

Michigan Journal of International Law

Nord. J. Int’l L.

Nordic Journal of International Law

OTP

Office of the Prosecutor

SACJ

South African Journal of Criminal Justice

Sri Lanka JIL

Sri Lanka Journal of International Law

SAYIL

South African Yearbook of International Law

Wis. Int. L. J.

Wisconsin International Law Journal

Yale Hum. Rts. & Dev. L. J.

Yale Human Rights and Development Journal

Yale J. Int’l L.

Yale Journal of International Law

Yale L. J.

Yale Law Journal