Arms Exports and the Threshold of Responsibility: Third-State Liability in Nicaragua v. Germany

This article was originally written in March 2026.

In March 2024, Nicaragua instituted proceedings against Germany before the International Court of Justice (ICJ), alleging that Germany’s continued authorisation of arms exports to Israel during the Gaza conflict violated fundamental norms of international law. The case, Nicaragua v. Germany, raises a difficult and unsettled question in contemporary public international law: when, if ever, does the sale or authorisation of weapons make a state legally responsible for the harm those weapons help produce? This article argues that while existing treaty regimes and the law of state responsibility recognise that arms transfers may, in principle, engage third-party responsibility where there is a foreseeable risk of serious international crimes, the current legal framework leaves significant uncertainty regarding the evidentiary threshold required to establish such responsibility. At stake is not only Germany’s export policy, but also the broader development of legal standards governing when arms-exporting states must suspend transfers in high-risk conflicts.

In its 1 March 2024 application, Nicaragua submitted that Germany had breached its obligations under Article I of the 1948 Genocide Convention and Common Article 1 of the 1949 Geneva Conventions by continuing to authorise military exports despite what it characterised as a serious risk that those weapons be used in violations of international humanitarian law in the Gaza Strip. Nicaragua framed Germany’s conduct not as direct participation in hostilities, but as unlawful facilitation. The nation requested provisional measures requiring Germany to suspend military assistance to Israel pending the Court’s final judgment. It also argued that ongoing exports risked irreparable harm to protected rights under the aforementioned treaties.

The Court addressed those requests in its Order of 30 April 2024. It declined to indicate provisional measures, concluding that the circumstances, on the evidence then available, did not justify the exercise of its emergency powers. Crucially, however, the Court did not dismiss the case. It kept the matter on its General List, signalling that the substantive issues remain open. This confirms that Nicaragua’s legal arguments are not without foundation and that the Court considers the underlying questions of third-state responsibility for arms transfers sufficiently plausible to warrant thorough judicial examination. In reaching its decision, the ICJ noted several assurances provided by Germany. It noted that German export licences were assessed on a case-by-case basis under a strict regulatory framework, that the volume of authorised exports had significantly decreased following the escalation of hostilities, and that much of the licensed material was not categorised as “war weapons.” It treated these assurances as part of the context when assessing whether the high threshold for interim relief had been met. Consequently, the refusal of provisional measures reflected a cautious on the basis that the requisite standard for intervention had not been met, rather than determinative.

The legal complexity of the case arises from the interaction between several treaty regimes, which, while aligned in purpose, differ in scope, obligations, and thresholds for state responsibility, creating interpretive and evidentiary challenges in assessing Germany’s conduct. This complexity is illustrated by the distinct roles of each regime: jurisdictionally, Nicaragua’s application before the International Court of Justice is grounded in the Convention on the Prevention and Punishment of the Crime of Genocide, whereas substantively, duties under the Geneva Conventions, particularly Common Article 1, govern the duty of states to ensure respect for international humanitarian law. Alongside these, although the Arms Trade Treaty (ATT) is not formally invoked in Nicaragua's claim and therefore does not establish the Court’s jurisdiction or create binding obligations in the proceedings, it provides an important analytical framework for evaluating how states should assess the risk that exported weapons may be used in serious violations of international law. Taken together, these three instruments clarify the substantive duties that Germany is alleged to have violated by continuing to authorise arms transfers to Israel despite the ongoing conflict in Gaza.

Articles I and III of the Genocide Convention oblige states not only to refrain from committing genocide, but also to prevent it. The Court has previously interpreted this as a due diligence obligation, requiring states to employ all means reasonably available to them to prevent genocide where they know, or should know, of a serious risk. Nicaragua's argument extends that logic to German exports: if the state is aware of a serious risk that genocide or grave breaches may be committed, continuing to authorise arms transfers that could facilitate those acts is incompatible with the duty to prevent. The critical issue is whether the duty to prevent extends so far as to require suspension of exports based on risk rather than certainty.

Common Article 1 of the Geneva Conventions further obliges states to “respect and to ensure respect” for international humanitarian law (IHL) in all circumstances. While the internal dimension of this obligation is clear — states must comply with IHL themselves — the external dimension is more legally contested. An emerging body of scholarship argues that “to ensure respect” entails a negative obligation not to aid or assist in violations by others, particularly where there is a foreseeable risk of misuse. With this interpretation, authorising arms transfers into a conflict marked by credible allegations of grave breaches could amount to a failure to ensure respect for IHL. Critics such as Kalshoven, Schmitt and Watts, Robson, and Focarelli caution against converting what was historically a diplomatic and cooperative arrangement into a basis for judicially enforced responsibility. The ICJ’s provisional measures order did not fully engage with this debate, leaving unresolved whether third-party arms exporters could be held legally accountably under Common Article 1 for contributing to violations of international humanitarian law.

The 2014 Arms Trade Treaty provides more explicit regulatory guidance for arms transfers, though it does not form part of the jurisdictional basis of the proceedings before the Court. Instead, it offers a useful analytical framework for assessing evidentiary thresholds such as “knowledge” and “overriding risk,” which are central to Nicaragua’s argument that Germany should have suspended export authorisations. Under Article 6, a state must not authorise a transfer if it has knowledge that the arms would be used to commit genocide, crimes against humanity, or grave breaches of the Geneva Conventions. Article 7 requires a forward-looking risk assessment and requires denial of export where there is an overriding risk of serious violations. The dispute therefore turns on how “knowledge” and “overriding risk” are interpreted: is awareness of widespread allegations and ongoing hostilities sufficient, or must there be a more direct and concrete link between the specific weapons authorised and anticipated unlawful conduct? Scholars have noted that ATT “knowledge” may involve either full awareness or foreseeability, which makes the evidentiary threshold for prohibition subject to debate. Germany contends that its export licensing decisions comply with the ATT by assessing, on a case-by-case basis, the foreseeable risk that the arms could be used to commit serious violations of international humanitarian law. Nicaragua, by contrast, argues that the ongoing large-scale harm demonstrates that continued authorisation is incompatible with the level of risk states are obliged to consider under the ATT when supplying arms in situations involving alleged violations of international humanitarian law. Although the Treaty is not directly invoked before the Court, its risk-assessment framework closely mirrors the normative questions at the heart of the dispute, making it a key reference point for evaluating the legality of contemporary arms export practices.

The broader doctrinal backdrop is the law of state responsibility, as codified in the United Nations International Law Commission’s Articles on Responsibility of States for Internationally Wrongful Acts (ARSIWA). Unlike the aforementioned treaties, ARSIWA does not create new obligations; rather, it establishes the legal framework for determining when a state is responsible for breaching an obligation alongside the consequences that may follow. Under Article 16, a state that aids or assists another in the commission of an internationally wrongful act may incur responsibility if it does so with knowledge of the circumstances and if the act would itself be wrongful if committed by the assisting state. In the context of arms transfers, the central challenges are causation and proximity, because weapons, as part of a complex military apparatus, are rarely the sole cause of harm. Establishing responsibility therefore requires not merely political alignment or general support, but a contribution that is both materially significant (addressing causation) and sufficiently connected to the wrongful act (addressing proximity), coupled with the requisite mental element. Germany’s defence rests heavily on the argument that authorising exports within a regulated system, particularly where the material is defensive or limited in scope, does not satisfy the threshold of knowing assistance in genocide.

On 21 October 2025, Germany challenged the Court’s jurisdiction and the admissibility of Nicaragua's claims. Germany denied facilitating genocide, maintained that Israel’s security is central to its foreign policy, and contended that the Court could not adjudicate Nicaragua’s claims without considering Israel’s conduct, a third state not party to the proceedings. ICJ Vice-President Julia Sebutinde had highlighted this concern much earlier, in her separate opinion on the Court’s 30 April 2024 provisional measures order. She noted that under the Monetary Gold Principle — which bars the Court from adjudicating a dispute that would affect the legal interests of a state not before it — prior rulings on Israel’s legal responsibility would be required to determine Germany’s conduct, as Israel was an indispensable third party. While initially peripheral, her observation became central once Germany formally raised its admissibility objections, as this procedural issue would determine whether the case could proceed.

Separately, Article 79bis(3) of the Rules of Court sets out the procedural effect of Germany’s filing: it automatically suspended proceedings on the merits and required the Court to set a deadline for Nicaragua to submit written observations and supporting evidence. In this way, by simultaneously invoking both the Monetary Gold Principle, which limits the Court substantively, and Article 79bis(3), which governs procedural handling, Germany effectively put the evidentiary hearings on hold, first pending Nicaragua’s response to its challenge and then the Court’s ruling on jurisdiction and admissibility.

By an Order dated 22 October 2025, the President fixed 23 February 2026 for Nicaragua’s response. According to expert commentary, Nicaragua has since submitted its written observations, and public hearings on Germany’s objections are likely to occur in mid to late 2026. The hearings will focus on whether the Court can lawfully continue the case without Israel as a party, in light of Germany’s Monetary Gold argument and related challenges. Only after the Court resolves these preliminary matters will it consider the substantive question of Germany’s potential legal responsibility for arms transfers to Israel, leaving broader issues regarding facilitation and third-state responsibility unresolved for the time being.

The implications of Nicaragua v. Germany extend far beyond the parties. Arms transfers are not unlawful per se and remain a recognised aspect of sovereign foreign policy. Yet, where there is a serious and foreseeable risk that such transfers could facilitate genocide or grave breaches of humanitarian law, the legal space for discretion narrows. If the Court finds that Germany’s exports violated its international obligations, other arms-exporting states could face stronger pressure to suspend transfers in high-risk situations, creating a precedent for holding states accountable for foreseeable harm. Conversely, if the Court requires a very high threshold of proof before attributing responsibility, states are likely to retain wide leeway in licensing decisions, reinforcing the status quo. Either outcome will help clarify how international law governs the responsibilities of arms exporters in conflicts marked by mass violence and could shape the evolving doctrines of preventative and facilitative responsibility.

Photo source: https://foreignpolicy.com/2024/04/08/nicaragua-germany-icj-hearing-israel-gaza-genocide/