IER Blog Series: Preliminary Examinations and Complementarity

This blog is part of a series on selected aspects of the ICC Independent Expert Review Final Report released on September 30, 2020.

In its focus on the Office of the Prosecutor (OTP), the Independent Expert Review (IER) devotes a substantial portion of its report to considering the pre-investigation, preliminary examination (PE) stage. The report analyzes the OTP’s broad approach to PEs, as well as its strategies with respect to the selection, prioritization, hibernation, and closure of cases. Closely connected to these considerations is the question of “positive complementarity,” which the report also addresses in some detail. 

Situation Selection and Prioritization

An overarching conclusion of the report is that “The greatest concern in terms of selection of situations for PEs, and later, for (requesting authorization for) investigations relates to the increasing number of situations before the OTP and its insufficiency of resources” (paras. 642-643). The experts also observed that a lack of long-term planning characterized the OTP’s approach and found that, on average, it takes about four years for the OTP to complete a PE, which they considered to be “untenable, damaging to potential evidence and other investigative opportunities, frustrating for the victims and civil society, and unsatisfactory to the States Parties” (para. 711).

With respect to situation selection, the experts note that about 90 percent of communications that undergo “Phase 1” assessment are ultimately dismissed (para. 639). On that basis, they recommend that the OTP make the criteria for opening examinations at this phase more explicit and transparent (R226) and consider adopting a higher gravity threshold (R227). Notably (and in contrast to the Pre-Trial Chamber’s reasoning in the much-criticized Afghanistan decision), they reject the view that feasibility – the likelihood of state cooperation and, ultimately, arrests – should be taken into account when deciding to open an investigation (R228). Such operational or strategic considerations could, however, help the Prosecutor decide whether to conduct an “active investigation” (para. 654).  


As both a legal principle and an instrument of policy, complementarity seeks to ensure that the ICC does not usurp national jurisdictions that are genuinely pursuing criminal proceedings, while also encouraging such proceedings. Such active encouragement has popularly come to be known as “positive complementarity,” a way to induce, nurture, or otherwise entice accountability at the domestic level through prosecutorial strategy, advice, and cooperation.

The IER found that one of the main reasons for the excessive duration of PEs is because of the OTP’s approach to complementarity. In its words, the office appears to conduct its admissibility assessments “prospectively or on a continuing basis, in some instances waiting for years for national authorities to demonstrate their ‘willingness and ability’” (para. 723). Added to this is a “complete lack of timelines or benchmarks,” which allows recalcitrant governments to delay and/or obfuscate. This, the experts conclude, “leaves the OTP unable to progress in situations where the domestic proceedings might be sufficient to persuade a Pre-Trial Chamber to deny the authorization of an investigation, but too little to justify the closure of the PE” (para. 727).

How to resolve this apparent paradox? As a matter of admissibility, the report recommends that the OTP should not consider prospective national proceedings “and focus solely on whether national proceeding are or were ongoing” (R262). Time limits should also be considered for compliance with OTP requests, as should “providing clear criteria” of what the OTP requires in order to make a determination (R263). As for positive complementarity, the IER takes a dim view of infusing such policy considerations into the PE phase, stating that PEs should be undertaken “solely with a view to determining whether to proceed with an investigation” (para. 730). In the experts’ view, the OTP should consider positive complementarity “in the context of the strategy for the situations at all stages of proceedings,” and not exclusively at the PE stage (R264). The investigation stage, in particular, may be a more appropriate context in which to undertake positive complementarity activities. The OTP could develop its case selection and prioritization in this stage with “clear prosecutorial goals,” and share information and evidence that “could be used to catalyze additional prosecutions, beyond the limited scope of the OTP” (paras. 693, 734-735). Positive complementarity should also be considered in the design of completion strategies (R265).

Timelines and Benchmarks

The IER’s endorsement of a “more systematic approach” to PE policy is linked to its call for a swifter, more holistic approach to the examination stage.  Noting that many actors have called in recent years for the establishment of time limits on PEs, the experts conclude that imposing such deadlines “is likely to be counterproductive” (para. 717). Rather, they call for an “overall plan for each PE, including meaningful benchmarks for the progress in each situation, each phase of the PE, and target deadlines” (para. 718). Seeing “little benefit” to the OTP’s current phased approach, the report recommends combining the Phase 2-4 reports into one, omnibus PE report “comprised of the assessment of subject matter jurisdiction, complementarity, gravity, and the interests of justice” (R254). As a rough guide, PE strategies should be developed on a two-year timeline, with exceptions granted by the prosecutor in exceptional cases (R257). The experts also reject the suggestion from some stakeholders that PEs be kept confidential, finding such an approach “impractical” and recommending that the OTP maintain its “current level of transparency in relation to PE activities” (R266, paras. 737-740).

A revamped approach to preliminary examinations would also bring improvements to the process of case selection and prioritization at the investigations stage. As the experts note, the absence of a more systematic approach means that “case selection is oftentimes made on the basis of ad hoc proposals from teams, rather than pursuant to a considered strategic plan” (para. 679). In order to be more strategic in its approach to case selection, the Prosecutor needs “situation-specific strategic plans” (R241) and a “situation-specific case overview document” (R242). Completion strategies are a crucial part of that planning but, as the IER notes, “appears to be absent from the planning of OTP operations” (para. 691)

What might the IER’s Conclusions mean for Complementarity’s Future?

The OTP’s reply to the expert’s report will be a telling indication of where and how it might revamp its strategy along the lines proposed. A new prosecutor, however, will take office in June 2021, and may well propose a different direction.

Regardless, the experts are certainly right to emphasize that the current situation is unsustainable, with the OTP’s current docket of situations and preliminary examinations having grown at a pace wildly disproportionate to its budget. Many of the recommendations the report makes echo concerns raised elsewhere about ICC prosecutorial strategy, particularly the need for clearer benchmarks of progress and a more disciplined approach for planned, responsible entry and exiting of situations. Sharpening the criteria and timelines for PEs might be more effective in pressing some states to act decisively, rather than just inching forward to earn a stamp of “some progress” and then doing only the bare minimum until the next visit from a senior OTP official. Marrying a more targeted timeframe for PEs to more astute, comprehensive, and situation-specific strategic plans also makes sense. Less clear is the report’s recommendation to lower the gravity threshold for PEs, which could lead to important situations falling outside of the ICC’s scrutiny.

One casualty of the IER appears to be the role and prominence of “positive complementarity” in prosecutorial strategy, as the report also takes a rather hard line in excluding those considerations from the PE process. This may make sense in certain contexts but, as other experts have noted, “policy and political considerations relating to positive complementarity and cooperation warrant allowing the OTP some flexibility on the length and conduct of PEs.” The suggestion that such policy considerations should only (or mostly) come into play after an ICC investigation is opened – or as part of a completion strategy – also risks foreclosing the benefits of building closer dialogue with domestic stakeholders early on. Indeed, those dialogues will likely be critical for building the kind of wider, more comprehensive prosecutorial strategies that the IER wishes to see, including the hope that governments themselves would initiate genuine national proceedings.