(Editor’s Note: This article is part of our new symposium on the ICC and the Israel-Hamas war.)

The Prosecutor of the International Criminal Court (ICC) Karim Khan’s recent announcement that his office has applied for five arrest warrants in the situation in Palestine, including against Israeli Prime Minister Benjamin Netanyahu and Defense Minister Yoav Gallant, has created significant turmoil. A cornerstone of the ICC system is the principle of complementarity, which gives priority to criminal investigations and prosecutions by national authorities that are genuine in nature and not designed to shield perpetrators from liability. Detractors and skeptics of the Prosecutor’s action with regard to the Israeli suspects have argued that his application is inconsistent with the ICC’s commitment to complementary, but their contentions do not withstand scrutiny.

Two key provisions of the Rome Statute, dictating the terms under which complementarity operates, are being misunderstood in relation to the situation in Palestine. Article 19 holds that the Court’s jurisdiction over a case may be challenged if there exists (or has existed) a national investigation or prosecution over the same alleged criminals and same alleged crimes as at the ICC. Only if that condition is met will it be scrutinized whether the State is (or was) “willing” and “able” to genuinely conduct such proceedings. As Mark Kersten has observed, while critiquing an article in The Economist that echoes Germany’s first reaction to Khan’s request, the fact that Israel is a democracy with an independent judiciary does not impact the first condition to be considered in Article 19 proceedings. Even skeptics of the Prosecutor’s action, such as Yuval Shany and Amichai Cohen, admit that Israel is currently not able to satisfy the first requirement for an inadmissibility challenge under Article 19, which necessitates an investigation of Netanyahu and Gallant for substantially the same conduct as found in the Prosecutor’s applications.

Secondly, Article 18 sets up a mechanism for the Prosecutor to notify national authorities of the prospect of the OTP opening of an investigation, thus giving States the opportunity to initiate proceedings of their own, and as such halt the OTP’s investigation. Article 18 remained unused for over 15 years after the Rome Statute came into force. Its drastic effect — a deferral to national authorities — was first applied with the Prosecutor’s investigation in Afghanistan in 2020. Since then, it has become a common tool for States, as shown by the initial deferrals in Venezuela and the Philippines, to halt an OTP’s investigation, at least until an ICC Pre-Trial Chamber authorizes its resumption. Shany and Cohen rest the weight of their complementarity argument on Khan’s request for arrest warrants on Article 18:

we questioned and continue to question whether the Prosecutor acted in a manner that afforded Israel a reasonable opportunity to claim complementarity before the issuance of an application for arrest warrants, in a manner that is fully consistent with the complementarity provisions of the Statute.

Similar contentions have been made by US Secretary of State Antony Blinken in a press statement issued on the day the Prosecutor applied for arrest warrants.

In this essay, I survey what Article 18 of the Rome Statute entails, its procedural obligations for the Prosecutor, and whether new notifications are required for new charges. I examine if an investigation can expand within the same crisis situation and question the need for a “situation in Palestine II” notification under Article 18, triggered by South Africa’s collective referral in November 2023. Ultimately, by analyzing the original situation referred by Palestine seven years ago and the strong connection to the alleged crimes in Prosecutor Khan’s request for arrest warrants, I contend that we are facing the same situation, albeit a dramatic escalation of it. The requirement of Article 18 have thus been satisfied by the notification issued years ago when the OTP turned its attention to the situation in Palestine. 

The Evolution and Application of Article 18 of the Rome Statute

Article 18 of the Rome Statute, which provides the framework for preliminary rulings regarding admissibility, is more generous to States than Article 19. When a situation is referred to the ICC or initiated by the Prosecutor, the Prosecutor must notify relevant States. If, within one month, a State informs the Court it is investigating or has investigated related crimes, the Prosecutor must defer to the State’s investigation. To overcome a deferral, the Prosecutor must apply to the Pre-Trial Chamber (PTC), which will come close, as Kevin Jon Heller notes, to judging “the overall functioning of a State’s legal system.” This review, unlike an Article 19 inadmissibility challenge, pertains to a newly opened situation with no specific cases yet. The State must show “an active process of domestic investigations and prosecutions of the same groups or categories of individuals related to the relevant criminality” within the situation (Philippines Deferral Appeals Decision, para 2). For the State’s investigations to merit the continuation of the deferral, they must “sufficiently mirror the scope of the Prosecutor’s intended investigation” (para 2) considering the “general parameters of the situation” (paras 106-107).

Regarding the situation in Palestine, the 2020 Preliminary Examination Report, issued by then-Prosecutor Fatou Bensouda, and the PTC Decision on Territorial Jurisdiction, which Bensouda relied upon to open the investigation, provide significant information relating to the Prosecutor’s intended investigation back in 2021, when an Article 18 notification was sent. The Preliminary Examination Report and the PTC Decision focused on alleged war crimes during the 2014 Gaza hostilities by the Israel Defense Forces (IDF), Hamas, and other Palestinian armed groups, as well as potential war crimes by Israeli authorities related to the occupation (PTC Decision, para 95). During the PTC proceedings, the Prosecutor also noted potential war crimes related to IDF actions against Gaza border demonstrators starting in March 2018 (during the so called “Great March of Return and the Breaking of the Siege”). Neither of these two documents contained allegations of crimes against humanity or the crime of starvation. However, as stated by Bensouda, the crimes noted are “illustrative only,” with the investigation able to “expand or modify” to include other acts or legal qualifications that are “sufficiently linked” to the situation (Ibid, paras 96, 100). She indeed wanted to make clear: “the situation in Palestine is one in which crimes allegedly continue to be committed” (para 100).

Bensouda kept the door open for the future OTP’s investigation. This is not really an issue. As the Appeals Chamber held in the Venezuela Deferral Decision, “there is no expectation at this stage of the proceedings that the Prosecutor should notify States of every act he or she intends to investigate,” especially in broad referrals covering many alleged criminal acts. However, the notification “must be sufficiently specific” for the State to assert its jurisdiction under Article 18(2) (para 110).

New Notification Needed?

Shany and Cohen’s argument is not about what details the Prosecutor must include in his Article 18 notification to enable the State to assert its jurisdiction and potentially defer the ICC investigation. Rather, their argument concerns whether Israel had a fair chance to invoke Article 18 with respect to the crimes that allegedly occurred since October 7, 2023. They write: “we are of the view that this practice is problematic in circumstances, where the new events being investigated significantly deviate in their features from the ‘defining parameters’ of the original notification.”

In a general commentary of the Rome Statute’s provisions, Melinda Taylor observes  in her discussion on Article 18 that the purpose of complementarity “would be frustrated if the Prosecution were to interpret its obligation as a once off obligation, as opposed to an obligation which is triggered whenever the Prosecution changes or expands the parameters of its investigations.” In her view, the Prosecutor would “need to reinitiate the ‘notification’ process if the crimes being investigated are not sufficiently linked to the crimes which formed the basis of the initial notification process.” She builds this argument on ICC case law regarding the definition of a “situation.”

In my view, this case law, which is surveyed in the next section, does not suggest that a new notification is needed if the situation is effectively a continuation of the original one. Article 18 aims to give relevant States a chance to assert jurisdiction at the preliminary stage of the investigation. It relates to other complementarity provisions, such as Article 53(1)(b), requiring the Prosecutor to analyze admissibility before initiating an investigation, and Article 19, allowing the accused and relevant States to challenge the admissibility of a case. Importantly, the Appeals Chamber in the Afghanistan Judgment found that PTCs should not consider admissibility issues when authorizing a proprio motu investigation under Article 15 (para 40). This effectively means that prior to the official opening of a situation, regardless of the trigger mechanism, the Prosecutor can bypass complementarity questions. Thus, Article 18 offers the first opportunity for States (which is not available in situations triggered by the Security Council) to assert the relevance of their own proceedings, with further opportunities arising through Article 19 challenges once a specific case is opened.

States should indeed seize the opportunity offered by an Article 18 notification when it arises, given the relative flexibility of the mirroring test at this stage. However, not doing so due to a lack of political will is not the Prosecutor’s problem; the system aims to incentivize States to undertake comprehensive investigations, not just those aligned with their own perceived interests.

While no obligation to notify arises when the investigation expands to include new cases or crimes, as pointed out by Thomas Obel Hansen, in the situation in Palestine the Prosecutor cannot be deemed guilty of launching a “surprise attack against Israel.” Indeed, “Israeli leaders have continuously been warned by Prosecutor Khan since the start of the Gaza War” that noncompliance with the law would force his office to take action in the expanding investigation, and “the Prosecutor has encouraged Israel’s military justice system to ensure compliance with international humanitarian law.”

New Situation?

The case law referenced by Taylor suggests that if the Prosecutor’s investigation is not sufficiently linked to the original situation, the Court lacks the power to exercise its jurisdiction over it. A new State or Security Council referral, or a request for the initiation of an investigation proprio motu, would be needed. This is why there are the situations in CAR I and II, DRC I and II, Venezuela I and II. The question then is should there be a “Palestine II situation,” triggered by South Africa’s collective referral of November 2023, and thus a new Article 18 notification?

In the Mbarushimana Arrest Warrant, the PTC questioned whether the charges fell within the scope of the situation referred by DRC President Joseph Kabila requesting the Prosecutor to investigate “the situation in my country since 1 July 2002, in which crimes within the jurisdiction of the International Criminal Court appear to have been committed.” The PTC ruled that subsequent prosecutions could only be initiated “within the boundaries of the situation of crisis for which the jurisdiction of the Court was activated,” including crimes committed after the referral if they are “sufficiently linked to the situation of crisis referred to the Court as ongoing at the time of the referral” (para 6). It then assessed whether the prevailing hostilities at the time of the referral were similar to those underlying the charges against Mbarushimana. In particular it verified whether, at the time of the referral, the hostilities already extended to South Kivu and Ituri provinces of the DRC, where the allegations against Mbarushimana occurred, and whether the Forces démocratiques de libération du Rwanda, the armed group in which Mbarushimana was the Executive Secretary, was already involved in military activities and crimes within the Court’s jurisdiction (para 7). Pre-Trial Chamber I used the same criteria  in Al-Werfalli Arrest Warrant to determine if the alleged crimes were “sufficiently linked” to the situation that triggered the Court’s jurisdiction in Libya (para 23).

With regard to the situation in Palestine, the 2018 referral was for “past, ongoing and future crimes within the court’s jurisdiction, committed in all parts of the territory of the State of Palestine” (para 9). The referral further highlighted specific circumstances, such as ‘the Israeli settlement regime’ and the IDF attack upon the Great March of Return, as well as applicable categories of war crimes and crimes against humanity but specified these are “not intended to limit the scope of the Prosecutor’s investigation” (para 12).

While the referral triggered the Court’s jurisdiction over all crimes committed by Palestinians or in the territory of Palestine, regardless of whether Palestinian crimes are mentioned, it cannot grant the Prosecutor an investigative carte blanche that would be valid ad infinitum. As emphasized by PTC I in Mbarushimana Decision on Jurisdiction, the requirement of sufficient links is crucial to avoid referrals becoming instruments “permitting a State to abdicate its responsibility for exercising jurisdiction over atrocity crimes for eternity,” which “would be wholly antithetical to the concept of complementarity” (para 16).

It may be questioned whether the recent ICC arrest warrant applications for war crimes and crimes against humanity concern a different situation than the one referred by Palestine in 2018. While the initial referral mostly — but not only — focused on the occupation, alleged annexation, alleged persecution and apartheid regime by Israeli authorities, Prosecutor Khan’s applications are about the Hamas attack of October 7 and the following “total siege” by Israel of Gaza. Moreover, none of the incidents noted in Bensouda’s Preliminary Examination Report or the PTC Decision on Territorial Jurisidiction, which presumably formed a large part of the OTP investigation thus far, are part of the charges. Under that reading, the 2023 collective referral triggered the Court’s jurisdiction over a new situation in Palestine, which could be termed “the situation in the Gaza War.”

In my view, this is a misinterpretation of the patterns and forms of criminality permeating the current Gaza War and its links with the crisis situation referred by Palestine in 2018. As the case law noted above indicates, to determine if a sufficient link exists with the original situation, it must be examined whether there is a general continuity between the main actors or groups involved and whether there is a connection between the contextual elements of the crimes. There are strong grounds to conclude that the charges in the arrest warrant applications (for both sides) exemplify an intensification of the original situation in Palestine, which had hitherto remained unaddressed. The actors involved — Israeli authorities, the IDF, and Hamas — were engaged in hostilities at the time of the 2018 referral. The contexts underlying the charges — hostilities between regular forces and armed groups, and widespread or systematic attacks against the civilian population — were allegedly ongoing at the time of the original referral. The total siege of Gaza, and the catastrophic hunger resulting from it, form the crux of the charges waged against Netanyahu and Gallant. This siege is an extreme form of the blockade which had been imposed on Gaza by Israel for more than a decade before October 7. According to the UN Office for the Coordination of Humanitarian Affairs in 2018, the blockade had already resulted in severe or moderate food insecurity for 68 percent of households in the Gaza Strip. The alleged war crimes and crimes against humanity by the IDF during the Great March of Return were against demonstrators demanding the end of the Israeli blockade and the right of return for refugees. Moreover, the blockade and the military occupation, which effectively denies the Palestinian people their right to self-determination and full realization of the Palestinian State, is crucial for contextualising the wholly unacceptable and unpardonable crimes committed by Hamas forces on October 7. Israel’s response, led by Netanyahu and Gallant, allegedly aiming “to collectively punish the civilian population of Gaza,” echoes the views of Israel former Defense Minister in 2018 that “there are no innocent people in the Gaza Strip.” The baseline situation is the same one that existed from the time of the initial referral, and the OTP’s allegations of crimes committed by the five leaders arises out of that continuing though escalatory situation.


A new investigation, necessitating a new Article 18 notification, was not undertaken following South Africa’s 2023 collective referral on the situation in Gaza. Viewing the application for arrest warrants as part of a separate situation stemming solely from the events of October 7 would disregard the broader history between Palestine and Israel and the longstanding effort by Palestine to have the ICC address crimes committed in Gaza and the West Bank, including East Jerusalem. It is, however, unfortunate that the investigation triggered by the Palestinian referral of 2018 is only now materializing in arrest warrant applications, just as the criminality that permeated the original crisis situation has dramatically exploded well beyond the point where justice should have intervened.


Image: The building of the International Criminal Court in The Hague in 2019. (Photo by OSeveno via Wikimedia Commons under Creative Commons license).