Paper presented at the Leiden University Symposium: Rules for a lawless world? The international legal order in an age of great-power struggle for normative primacy
The paper aims to, first, describe the growing gap between legal clarity and political prevarication, a schism of norms on the one hand, and humanitarian and political realities of Palestine on the other.
Second, it outlines the consequences for third parties – states and intergovernmental organizations – owing to the ‘war of debilitation’ on peremptory norms and what they represent for a collective legal project.
Finally, it proposes a way forward, or in other words, an articulation of what needs to be done to close the accountability gap for Israel's systemic breach of jus cogens norms.
In the words of Lord Peter Millett, “international law cannot be supposed to have established a crime having the character of jus cogens and at the same time to have provided an immunity which is co-extensive with the obligations it seeks to impose.”
The International Court of Justice’s July 2024 advisory opinion concluded that Israel’s continued presence in the occupied Palestinian territory is unlawful, owing to serious violations of peremptory norms of general international law, inter alia, the prohibition on the acquisition of territory by the use of force, the basic rules of international humanitarian law, including the duty to administer occupied territory temporarily and in good faith, and the suppression of the right to external self-determination.
The Court held that Israel’s presence must end unconditionally and rapidly, and that third states and intergovernmental organizations must neither recognise as lawful nor assist in maintaining the unlawful situation.
One hoped that the Court would be more prescriptive, but it was of the view that the precise modalities to end Israel’s unlawful presence in the oPt is a matter to be dealt with by the General Assembly, which requested this opinion, as well as the Security Council. I will come back to the latter in a moment.
In September of last year, the General Assembly adopted Resolution ES-10/24 by a vote of 124 in favour, 14 against, and 43 abstentions. The resolution emphasizes the urgency of redressing Israel’s wrongful acts within a specific timeframe and explicitly demands that Israel end its unlawful presence and withdraw within twelve months. It also calls for comprehensive reparations, accountability mechanisms, and lawful countermeasures against entities supporting the illegal situation.
The resolution is in keeping with the legal findings of the Court – including where it guides the UN General Assembly to establish precise modalities for the implementation of legal obligations set out – and an essential step in aligning international action with established principles of international law, notably the prohibition on acquiring territory by force and the protection individual and collective rights of Palestinians under Israeli occupation.
The advisory opinion and the UNGA resolution had a paradoxical effect. In the West Bank, Israel has made decisive moves towards entrenching its colonization and annexation. The transfer of legislative and administrative powers from military to civilian Israeli authorities effectively extends Israeli domestic governance over the occupied territory.
Record levels of settlement construction, land seizures, and destruction of Palestinian property are transforming the physical landscape in ways that render withdrawal increasingly unlikely. These developments meet the ICJ’s criteria for a permanent, acquisitive occupation and breach the prohibition on aggression.
Compounding this is Israel’s deployment of military force in the West Bank, which could be best described as increasingly resembling open warfare. The West Bank has also seen an alarming increase in extrajudicial executions and the forced displacement of over 100,000 refugees. Israel applies the more permissive rules of armed conflict to a setting where such a shift is legally unjustifiable, resulting in arbitrary killings, destruction of civilian property, and mass forcible transfer without accountability.
In Gaza, where the ICJ has reaffirmed Israel’s status as the occupying power, the situation is increasingly injurious; it is beyond catastrophic. The March 2024 ICJ order in the Genocide Convention case required Israel to ensure “unhindered provision at scale” of humanitarian assistance.
The paradoxical effect applies here as well. Systematic restrictions, including the absolute blocking of food, shelter, fuel, and medical supplies, the sabotage of aid delivery, and the expulsion of UNRWA and international non-governmental organizations, brought the civilian population to the extremes of deprivation and want. These acts amount to the use of starvation as a method of warfare, a grave breach of International Humanitarian Law (IHL), codified as a war crime.
As the Independent International Commission of Inquiry maintained with respect to attacks directed at primary healthcare and obstetrics, the assault on the right to receive and provide humanitarian relief is an “intrinsic element of the broader assault on the physical and demographic infrastructure of Gaza, in violation of international humanitarian law and the Palestinian people’s right to self-determination,” as well as a stark contravention of provisional measures ordered by the ICJ in the Genocide Convention case.
To put this differently, a paradox is apparent when the right of the Palestinians in Gaza to be protected from acts of genocide and related prohibited acts identified in Article III of the Genocide Convention, is egregiously breached by Israel’s noncompliance with the orders of the Court; and the community of states fails to enforce those, including through recourse to the Security Council pursuant to Article 94 of the UN Charter.
To borrow from the field of medicine, paradoxical reactions - when a medication causes an effect that is the opposite of what's expected – have not been fully clarified by scientific research. In the field of international law, we may have an answer.
As the Court maintained, Israel’s internationally wrongful acts give rise to international legal responsibility for the State of Israel, all States, and international organizations, including the United Nations.
That much we know. All states have a duty to cooperate with the General Assembly and the Security Council on implementing modalities and measures to bring the internationally wrongful acts identified in the advisory opinion to an end.
Rhetorically, they acknowledge the ICJ’s authoritative findings. Case in point, in February, the 13th meeting of the EU-Israel Association Council was held, and a common position was adopted, in which the “ EU underlines that the International Court of Justice has found that the continued presence of Israel in the occupied Palestinian territory is unlawful, rejecting any attempt at demographic or territorial changes and stressing the importance of unifying the Gaza Strip with the West Bank under the Palestinian Authority.”
In practice, third states have largely failed to act on their legal obligations of non-recognition and non-assistance. These patterns of inaction enable not only Israeli violations, but risk creating “a wider precedent whereby serious violations of international law”—including annexation, denial of self-determination, and the targeting of civilians—are met with little more than condemnation.
At the epicentre of a failed attempt to have jus cogens norms serve as a constraint on power resets in inglorious paralysis, the Security Council. It has to date done nothing to give effect to the ICJ ruling or enforce its own resolutions that aim to reverse Israel’s acquisition of territory by force.
Former US Prosecutor at the Nuremberg Military Tribunals, Ben Ferencz, used to recall that the Tribunal referred to the crime of aggression "[...] not only an international crime, it is the supreme international crime. It contains within itself the accumulated evil of the whole."
In 1974, the US - encouraged by Fernecz - supported the adoption of UN General Assembly Resolution 3314 on the definition of aggression, as, inter alia, the "invasion or attack by the armed forces of a State of the territory of another State, or any military occupation, however temporary, resulting from such invasion or attack, or any annexation by the use of force of the territory of another State or part thereof."
It has been particularly painful to have attempted to persuade members of the Security Council to establish an ad-hoc committee to comprehensively review the non-compliance and propose mechanisms to ensure implementation of the 2024 advisory opinion – such as the subcommittee established pursuant to UN Security Council resolution 276 following the Namibia opinion – only to see the United States threaten to use its veto power.
It goes beyond this paper to elaborate on whether Permanent Members of the Security Council should not be allowed to exercise their veto when this is contrary to the obligation to uphold peremptory norms of international law.
This must be said: during the 2024 advisory proceedings, Spain maintained that “it is an indisputable reality that the situation in Palestine has worsened; and that resolutions of the Security Council and the General Assembly have repeatedly condemned the actions of the parties and repeatedly demanded the cessation of violations of international law.” However, such resolutions have failed to establish effective redress and sanction measures.
It then proceeded to ask the Court to “determine whether the obligation of all States to cooperate to bring to an end any serious violations of peremptory norms entail, within the Security Council in particular, the duty to not prevent, hinder or delay collective action in favor of the peaceful resolution of the conflict.”
An answer did not come, at least not yet. It should be argued, in my view, that the duty to bring violations of peremptory norms to an end is a secondary obligation that shares the character of the primary norm as jus cogens. This necessarily means that violations of these secondary norms entail the same consequences as violations of the primary peremptory norms.
The systemic failure to implement binding legal findings is not simply a matter of institutional inertia, division, or paralysis—it reflects deliberate political choices that privilege transitory alliances over legal consistency. More than one permanent member of the Security Council is at fault.
The way forward should be clear. It is clear. Robust measures by third states—including recognition of illegality and withdrawal of aid to Israel in entrenching its unlawful presence, and equally, a political investment in the realization of Palestinian political independence and permanent sovereignty.
This should include a comprehensive review of current practices to ensure compliance with international law, with the full gamut of measures of retorsion and lawful countermeasures in mind. The menu is well known to state actors, with an almost infinite variety of measures, whether legislative, executive, or administrative.
In short, applying measures of retorsion, such as the halting of ongoing negotiations or refusing to ratify agreements already signed, the non-renewal of trade privileges, and the reduction or suspension of voluntary public aid; and adopting lawful countermeasures such as arms embargoes, trade and financial restrictions, flight bans, and the reduction or suspension of aid and cooperation agreements.
States should also resort to penal measures to repress violations of humanitarian law, and support national and international efforts to bring suspected perpetrators of serious violations of international humanitarian law to justice.
Extensive menu, little appetite. In other words, the existence of a legal duty in the form of the obligation to ensure respect for jus cogens prevents states from using mere political considerations to claim that no step can be taken under that obligation.
The fact that the fulfilment of an international obligation can prove to be politically difficult cannot serve as grounds to refuse to take any measure in the implementation of that obligation. This would run against the very nature of a legal obligation as opposed to transitory political preference.
The international legal order’s failure in Palestine is not just about one case; it is about the precedent set when law bends to power, and what that means for future conflicts, the protection of civilians from the scourge of war, and the normative project of international law itself.
Former ICJ President Nawaf Salam noted in last year’s proceedings that:
“The obligation to ensure respect is not satisfied by mere diplomatic protests, or solely by cooperating with the United Nations. Indeed, as the Court has emphasized with regard to the crime of genocide, a State’s referral of a violation of obligations erga omnes to the organs of the United Nations does not relieve other States of their obligations to take such action as they can to ensure respect for those obligations and prevent or punish violations thereof.”