HIGHLIGHTS

ICC Appeals Chamber Rejects Israel’s Challenge to Notification of Investigation, Reinforcing Court’s Reach Over Non-State Parties

Highlights

• The ICC Appeals Chamber, by a narrow 3–2 majority, upheld the admissibility of the case against Israeli Prime Minister Benjamin Netanyahu and former Defence Minister Yoav Gallant, rejecting Israel’s argument that it was never properly notified of the investigation into the situation in Palestine.
• The Chamber held that a 2021 notification covering crimes committed in the Palestine situation since 2014 was sufficient to satisfy the Prosecutor’s obligations under Article 18(1) of the Rome Statute, even though it did not specifically identify the events following the 7 October 2023 Hamas attack and Israel’s subsequent military response.
• The ruling has important implications for the practical application of the principle of complementarity, particularly in relation to states that are not parties to the Rome Statute.
• The decision removes one procedural obstacle to the proceedings against Netanyahu and Gallant, while separate jurisdictional challenges remain.

Background of the Dispute

The dispute arose following the 7 October 2023 Hamas attack on Israel and Israel’s subsequent military campaign in Gaza.

In May 2024, the Prosecutor of the International Criminal Court (ICC) sought arrest warrants against Israeli Prime Minister Benjamin Netanyahu and former Defence Minister Yoav Gallant in connection with alleged war crimes and crimes against humanity. In November 2024, Pre-Trial Chamber I issued the warrants after rejecting initial jurisdictional objections raised by Israel.

Israel, which is not a party to the Rome Statute, has consistently challenged the ICC proceedings. It has argued that the Court lacks jurisdiction over its nationals and that the Prosecutor failed to comply with the procedural requirements governing the opening and conduct of an investigation.

A central issue was Article 18(1) of the Rome Statute. The provision requires the Prosecutor to notify states concerned when an investigation is initiated, giving the relevant state an opportunity to investigate the conduct itself. This mechanism is closely connected with the ICC’s principle of complementarity, under which national courts generally have priority where a state is genuinely investigating or prosecuting the relevant conduct.

Israel argued that it was never properly notified that the ICC investigation specifically covered the events occurring after 7 October 2023.

The only formal notification relied upon by the Prosecutor was issued in March 2021. That notification concerned crimes allegedly committed in the Palestine situation generally from June 2014 onward.

According to Israel, the post-October 2023 events represented a new and significantly different body of alleged conduct. It therefore argued that a fresh and specific notification was necessary before the Prosecutor could proceed against Israeli officials in relation to that conduct.

Israel maintained that, without such notification, it had been deprived of a meaningful opportunity to investigate its own nationals and invoke complementarity.

What the Appeals Chamber Decided

On 15 December 2025, the ICC Appeals Chamber rejected Israel’s challenge by a 3–2 majority.

The majority concluded that the Pre-Trial Chamber had not erred in treating the 2021 notification as sufficient for the purposes of Article 18(1).

The majority reasoned that Article 18(1) does not necessarily require the Prosecutor to issue a new notification every time an existing investigation develops a particular focus or encompasses additional events within the broader situation already notified.

In the majority’s view, the original notification could sufficiently cover subsequent conduct where the relevant events fell within the broader situation and temporal scope of the investigation.

Consequently, the absence of a separate notification specifically identifying the events following 7 October 2023 did not, by itself, invalidate the proceedings.

The Dissenting Opinions

The decision was not unanimous.

Two judges dissented, taking the view that the nature, scale and gravity of the events following 7 October 2023 were sufficiently distinct to require a renewed and more specific notification.

According to the dissenting position, particular fairness considerations arose because Israel is not a State Party to the Rome Statute. A specific notification would have provided Israel with a clearer opportunity to exercise its domestic investigative authority before the ICC proceeded further.

The dissenting opinions are therefore likely to be significant in future litigation concerning the scope of Article 18(1), particularly where investigations concern states outside the Rome Statute system.

Complementarity and the Right to Investigate Domestically

The Appeals Chamber also rejected Israel’s broader argument that the absence of a fresh notification deprived it of its ability to rely meaningfully on complementarity.

The Chamber distinguished between two separate questions:

1. Whether the Prosecutor had properly complied with the notification requirement under Article 18(1); and
2. Whether the case was admissible under the complementarity principle under Article 17.

The Chamber found that Israel remained capable of raising complementarity arguments at subsequent stages of the proceedings and had, in fact, raised such arguments.

Accordingly, the finding that the 2021 notification was adequate did not automatically prevent Israel from challenging the admissibility of particular cases on substantive complementarity grounds.

Significance for Non-State Parties

The ruling has broader implications for the ICC’s relationship with states that have not ratified the Rome Statute.

By declining to require a new Article 18(1) notification whenever an existing investigation develops a more specific focus, the Appeals Chamber has adopted an approach that gives the Prosecutor considerable flexibility in defining the scope of an investigation.

For non-party states, however, this may raise concerns about the extent to which they must be specifically informed before the ICC can proceed against their nationals.

The decision leaves several questions open, including:

• How broadly can an Article 18 notification be framed while still satisfying the Rome Statute?
• When does a change in the focus of an investigation become sufficiently substantial to require a fresh notification?
• What level of specificity must be provided to a non-party state?
• To what extent can a state subsequently rely on complementarity after an Article 18 notification has already been found adequate?

These questions are likely to arise in future ICC proceedings involving states that have not accepted the Court’s jurisdiction through ratification of the Rome Statute.

The Decision Does Not Determine Guilt

Importantly, the Appeals Chamber’s decision does not determine whether Netanyahu or Gallant are guilty of the alleged war crimes or crimes against humanity.

The ruling concerns a procedural challenge relating to the Prosecutor’s notification obligations under Article 18(1).

It therefore should not be understood as a determination on the merits of the allegations contained in the arrest warrants.

The decision nevertheless has practical significance because it removes one procedural obstacle that Israel had relied upon to challenge the ICC proceedings.

Israel’s Separate Jurisdictional Challenge

Israel’s broader challenge concerning the ICC’s jurisdiction over Israeli nationals remains a separate issue.

Israel has relied on Article 19 of the Rome Statute to challenge the Court’s jurisdiction, including its authority to exercise jurisdiction over Israeli nationals in the circumstances of the Palestine situation.

That jurisdictional dispute is distinct from the Article 18 notification issue addressed by the Appeals Chamber.

The outcome of the remaining jurisdictional proceedings could therefore have significant implications for the Court’s ability to continue exercising jurisdiction over Israeli officials.

What Comes Next?

The Appeals Chamber’s rejection of Israel’s Article 18 challenge allows the proceedings concerning Netanyahu and Gallant to continue without the notification issue preventing further action.

The remaining jurisdictional and admissibility questions will continue to be litigated before the ICC.

The decision is also likely to become an important reference point in future cases involving non-State Parties, particularly where a state argues that it was not adequately informed of the specific conduct being investigated.

Israel has publicly criticised the ICC proceedings and characterised them as politically motivated. The Court and its supporters reject that characterisation and maintain that the proceedings are based on the Court’s legal mandate under the Rome Statute.

Conclusion

The ICC Appeals Chamber’s 3–2 decision represents an important procedural ruling on the relationship between Article 18 notification, Article 17 complementarity and the rights of non-State Parties.

By holding that the Prosecutor’s 2021 notification was sufficiently broad to encompass the relevant investigation, the majority declined to impose a requirement for a fresh notification whenever an existing situation investigation focuses on subsequent events.

For Israel, the ruling removes one significant procedural objection to the proceedings against Netanyahu and Gallant. For the ICC more broadly, it strengthens the Court’s ability to pursue investigations involving nationals of states that have not joined the Rome Statute.

At the same time, the closely divided nature of the judgment and the concerns expressed in the dissenting opinions demonstrate that important questions remain unresolved about the limits of Article 18 notification and the practical operation of complementarity.

The decision therefore represents not merely another procedural development in the Palestine situation, but a potentially significant precedent for the future exercise of international criminal jurisdiction over nationals of non-State Parties.