The Forthcoming ICJ Advisory Opinion on Israel/Palestine and the Doctrine of Illegal Occupation


| Feb 20, 2023


On January 9th, 2023, the UN General Assembly requested the International Court of Justice (ICJ) to provide an advisory opinion on two questions. The first concerns the legal consequences arising from

the ongoing violation by Israel of the right of the Palestinian people to self-determination, from its prolonged occupation, settlement and annexation of the Palestinian territory occupied since 1967, including measures aimed at altering the demographic composition, character and status of the Holy City of Jerusalem, and from its adoption of related discriminatory legislation and measures.

The second question asks how do these practices “affect the legal status of the occupation” and the legal consequences that arise for third parties from this status.”

Thus, while the first question concerns the legal consequences of specific practices and policies, the second question asks whether these, in aggregate, affect the status of the occupation as a whole. In other words, the General Assembly asks the court whether the occupation itself is or has become illegal. This differs markedly from the General Assembly’s previous request, in 2004, for an advisory opinion on Israel’s occupation, in which the Court was requested to opine on the legality of a specific measure, namely the construction of a wall which encroaches into the West Bank.

The Questions’ Significance

The political context which underlies the phrasing of these questions now is the position of recent Israeli governments. In the past, Israel has insisted that its occupation is temporary, pending a negotiated agreement with the Palestinians. While the establishment of Israeli settlements in the occupied territories has always raised doubts whether this position was in fact genuine, this was the formal point of departure. Recent governments, however, have largely abandoned this attitude. The current Netanyahu government has even declared that Jews have exclusive rights in the West Bank, and has pledged to promote policies which have been described as de facto annexationist. This approach has in all likelihood made it easier for the Palestinians and their allies to gain the support needed to refer such questions to the ICJ. This is because, as this post shows, the notion of temporariness is central to the debate on the possible illegality of an occupation.

The question of occupation and illegality is more complicated than it perhaps initially seems. While it seems entirely commonsensical to ask whether any given situation can be said to be illegal under international law, the nature of the law of occupation, as part of jus in bello (or international humanitarian law (IHL)), complicates the question. As readers of Articles of War will know, the laws of war establish a separation between jus ad bellum and jus in bello, according to which the latter is assessed in isolation from larger questions of the legality of a belligerent’s war. On this orthodox view, even if a belligerent routinely violates norms of jus in bello, this alone cannot make its war unlawful as a whole.

Applied to the law of occupation, the same argument would be that violations of the law of occupation are just that: violations under jus in bello, which cannot make an occupation unlawful as a whole. Accordingly, one traditional view is that occupation is simply a factual condition regulated under jus in bello, just like any other military operation. It is simply “a natural phenomenon in war,” according to Dinstein. And indeed, although the Palestinians argued for decades that the Israeli occupation is “illegal,” most international responses assessed specific Israeli policies and conduct in the occupied territories, leaving the bigger question of legality unaddressed.

However, it is questionable whether occupation can be treated just like any other military operation under jus in bello. This is because this branch of IHL has its own unique foundational principles: mainly, that occupation does not confer sovereignty or title; that the occupant is merely a trustee in the territory; and the assumption that occupation is temporary. Quite possibly, a violation of these foundational principles entails illegality that is wider than the unlawfulness that follows isolated violations of IHL.

The forthcoming advisory opinion might be an opportunity for the ICJ to clarify this question. Is the law of occupation just another component of jus in bello, and accordingly, its violations should be viewed as separate unlawful acts? Or is there something unique about the law of occupation which can give rise to overall legality? Recent thinking on the law of occupation has gravitated towards the latter position, suggesting situations in which an occupation can become unlawful. In the remainder of this post, I will highlight some of these possible approaches. I will not delve into the specific question of the legality of the Israeli occupation, which requires a separate piece of its own. I will also not address in detail the legal consequences that might follow such illegality.

Occupation and Illegalities

One way in which an occupation can be considered unlawful has to do with the lack of legal justification for the use of force that has led to the occupation. If, under international law, the use of force is lawful only as self-defense or with the authorization of the UN Security Council, then an occupation which cannot be justified under these terms would be part of an unlawful whole. In such situations, even if the conduct of the occupant conforms with jus in bello, this does not “cure” its core wrongfulness.

For example, an occupation can be product of a war of aggression, as is clearly the case in relation to Russia’s invasion of Ukraine. Since aggression is a violation of a peremptory norm (jus cogens), it could be said that States are obligated to recognize such occupations as unlawful on the whole (non-recognition). Relatedly, an occupation can be illegal overall even if it results from initially lawful self-defense. If territory is held well after the threat from the attacking State has subsided, then maintaining the occupation of that State’s territory could be an unnecessary and disproportionate use of force. The same applies when a State that was once mandated to administer a territory remained there after its mandate ended. The best known example is South Africa’s continuing control of Namibia long after its mandate has been terminated.

Importantly, these approaches require the recognition that jus in bello alone does not confer “perfect” legality on an action, but merely provides immunity for combatants that adhere to it. If this is the case, it follows, for instance, that a commander who orders security measures in occupied territories which are lawful under jus in bello, would be immune from prosecution on that basis. However, the occupying State can still be held accountable under the law of State responsibility for such actions if conducted in the context of an unlawful use of force.

Beyond jus ad bellum, several other accounts have challenged the idea that violations of the law of occupation are merely separate violations of jus in bello. The theoretical impulse that seems to drive these suggestions is that the law of occupation seeks to give effect to principles that go beyond the usual principles of IHL such as distinction, proportionality, and necessity. On this view, the law of occupation is supportive of broader norms such as the right to self-determination and the prohibition on annexation. The role of the law of occupation can be therefore viewed as assisting the occupant not to slide into these manifest illegalities. Accordingly, when an occupation in fact becomes indistinguishable from such unlawful regimes, it could be said to be illegal as a whole.

Indeed, some scholars sought to find principles internal to the law of occupation, the violation of which would spawn illegality on the basis of foundational norms of international law. For example, Benvenisti has suggested that when an occupant refuses to promote a peaceful settlement of the dispute, this might render its occupation per se illegal. On this view, this behavior reveals that the occupant acts in bad faith, as it holds the territory not for legitimate security reasons but for other purposes such as de facto annexation.

Ben-Naftali, Gross, and Michaeli, for their part, have criticized the “factual” approach that views occupation as a neutral construct, and called for an analysis of occupation as a normative phenomenon which can be subjected to judgments of legality and illegality. On this view, violation of one of the three basic tenets of the law of occupation – (a) non-annexation; (b) occupation as trusteeship; and (c) temporariness – make an occupation unlawful per se. In his recent book, Gross suggested, in this context, a distinction between jus ad occupation and jus in occupation. The former consists of these three basic principles, while the latter comprises the specific norms of the law of occupation. Violations of jus ad occupation, to Gross, render an occupation illegal. Imseis has also argued that when an occupation violates peremptory norms it becomes an internationally wrongful act that must be terminated, without any precondition, and without any requirement of previous negotiations.

Of course, the former approaches give rise to broader questions concerning the possible effects of illegal occupation, which can be mentioned here only in passing. Does the illegality of occupation entail, for example, that all of the occupant’s actions are ipso facto unlawful? On the one hand, by extension of the Human Rights Committee’s position in its General Comment 36 –according to which all killings pursuant to aggression are ipso facto violations of the right to life – it is possible to argue that all measures that infringe human rights during an unlawful occupation are per se violations of international human rights law. Additionally, unlawfulness might trigger the duty of non-recognition, the exact content of which raises complex questions. On the other hand, there is a well-established doctrine in international law, according to which even acts that are undertaken under an unlawful regime may be recognized internationally, if they benefit the local population (the Namibia exception). Applied to unlawful occupation, this might mean that the consequences of illegality might be different in relation to different actions of the occupant, in light of their effects on the local population.

In sum, the questions referred to the ICJ have immense theoretical and doctrinal importance – beyond their obvious political explosiveness. Time will tell whether the ICJ chooses to address them head-on. Only one thing is certain: the ICJ’s advisory opinion will be heavily criticized either way.


Eliav Lieblich is Professor of Law at the Buchmann Faculty of Law, Tel Aviv University. He is the co-author of Occupation in International Law (OUP 2022).


Photo credit: Oren Rozen