The area encompassing Israel and the Palestinian territories has, for over seven decades now, created innumerable humanitarian and political dilemmas, and raised some of the most difficult questions in the history of international law, not even mentioning inexplicably complex moral dilemmas. 

The latest round of escalation only adds to these complex questions. To understand it fully, to distinguish between right and wrong, it should be analyzed through the lens of international law. Especially in times of extreme violence, humanitarian catastrophes, and overflowing emotions, knowing where the law stands is more important than ever, before one comes to any judgment. This text will consider a potential Israeli counter-attack into Gaza in light of jus ad bellum, the law of legally entering into war. Jus in bello, or international humanitarian law, will also briefly be examined.

Jus ad bellum: To Enter into War

Although the exact borders of Israel are subject to controversy, it is a sovereign state by all measures of international law. As such, Israel enjoys the right to self-defense; both under the UN Charter and customary law.

Israel is specifically claiming self-defense by declaring war on Hamas in response to Hamas’ armed attack on Israel. This raises the obvious question of whether the right to self-defense can be invoked against non-state actors (NSA) when no state attribution is present. Textually, Article 51 does not clarify whether an armed attack needs to come from another state or not, and some scholars have taken the position that this lack of clarification is already enough to justify self-defense against NSAs without state attribution. However, the International Court of Justice (ICJ) has thus far been reluctant to agree with such a blanket extension of the right of self-defense (see here in paragraph 195).

In the Wall Advisory opinion, the ICJ suggested that self-defense cannot be invoked when a country, Israel, is responding to attacks coming from territory under its own control (para. 139). Yet that case concerned the West Bank; currently, Israel is launching an offensive into Gaza, which it, by no definition, can be said to be occupying, even if it claims the territory. In the Armed Activities case, the court explicitly took no position on the question (para. 147). Since 9/11, states have repeatedly argued that a right to self-defense against non-state actors existed, often with passive or active acceptance by the international community. In the US case, the international community overwhelmingly accepted America’s right to defend itself—Security Council Resolutions 1368 and 1373, for instance, reaffirmed the US’ right to self-defense in light of the 9/11 terrorist attacks, along with a unanimous NATO statement. It can be argued, therefore, that the landscape of international law and the interpretation of the scope of the right to self-defense have changed fundamentally since 2001, and that the ICJ has not made a wholesale ruling on the matter since. Both the Wall Advisory opinion and Armed Activities case have peculiar circumstances, and the court did not generalize either ruling. The only certain conclusion that can be drawn from the ICJ’s jurisprudence is that state attribution is necessary if self-defense is to be invoked against another state. As outlined above, this is not the case here.

Judge Simma in his separate opinion in the Armed Activities case argues that “large-scale attacks by non-state actors can qualify as ‘armed attacks’ within the meaning of Article 51,” making reference to Resolutions 1368 and 1373 (paragraph 11). Judge Kooijmans opinion in that case further supports this view (paragraph 30). However, how would the situation play out if the ICJ took a different stance?

So far, statements by the international community point towards opinio juris supporting Israel in its invocation of self-defense. As many states have recognized, it would be an unreasonable assumption that Israel cannot react in self-defense to a terrorist attack that already required the deployment of Israel Defense Force units on Israeli soil. Geographically, it would be easy to equate the current situation with that in the Wall case.  The ICJ denied the self-defense claim, as Israel was the occupying force over the territories it claimed to be invoking self-defense against. However, Israel’s control over Gaza is fundamentally different from that of the West Bank. While it has in parts established effective control over the West Bank, Gaza is literally fenced off from the rest of Israel. Gaza is separately governed and controlled by Hamas, Israel exercises comparatively little influence, thus making this attack a sufficiently “internationalized phenomenon.” Although Israel’s control over Gaza’s borders and airspace must be noted, this itself does not qualify as an occupation or effective control. Another key feature that makes the 9/11 comparison, rather than that of the Wall case, more apt is the magnitude of the attack: 1400 dead, killed by over 1500 terrorist-militia that could only be expelled by military force. Even if some prior instances of attacks by NSAs were not deemed to warrant a response through the right to self-defense, such cases were of drastically different scale and effect.

In Nicaragua, the ICJ held that incursions of armed bands into the attacked state constituted an armed attack, questions of effective control temporarily put aside (paragraph 195). Hamas’ attack on Israel seems to fit this description quite closely. Some countries and scholars even take the position that any incident involving the use of armed force constitutes an armed attack. Although there is no one threshold for when an attack is of sufficient gravity to trigger the right to self-defense, one must reasonably conclude, based on the “scale and effects” of Hamas’ incursion, that Israel was the victim of an armed attack. Here, it is important to note that, just because Hamas’ attacks can be equated to an attack that triggers self-defense, that does not qualify them as being a sovereign state. If this were the case, then Israel’s use of Article 51 would be even more clear-cut.

Summarizing these two arguments, Israel is legitimately invoking self-defense against an armed attack.

Even if this interpretation were to be rejected, however, the question arises what part of international law would be violated by Israel’s counter-attack. Neither Hamas nor Gaza fulfill the criteria to qualify as sovereign states. There is no clearly established territory, and Hamas-controlled Gaza is not able to independently administer its foreign or domestic policy.

Even if the argument of self-defense is rejected, Israel is still not infringing on the sovereignty of another state. Article 2(4) of the Charter prohibits violence against “the territorial integrity or political independence of any state.” Regardless of how Israel would justify the attack, they are not violating either provision. Following this line of reasoning, Article 51, as an exemption to Article 2(4), cannot be invoked since Article 2(4) was never violated in the first place. As long as Israel does not commit any jus cogens violations or other acts that would trigger obligations erga omnes, international law is not being broken. If, on the other hand, Gaza were to be treated as a sovereign state, then the discussion around self-defense against NSAs becomes moot and Israel could invoke traditional self-defense.


Considering Jus in bello

While Israel has ratified the Geneva Conventions, these only apply to international armed conflict or conflict between two high contracting parties. Unlike Palestine, Hamas has not declared itself a high contracting party to these conventions. Thus, as there is only one high contracting party present in this non-international armed conflict—as Gaza is not a state—the only provisions of codified international humanitarian law (IHL) that could apply are Common Article 3 and Additional Protocol II, both of which apply to non-international armed conflict. However, Israel never ratified AP II—leaving only Article 3 and customary IHL.

It is too soon to tell whether there are any clear IHL violations. Common Article 3, pertaining to non-international armed conflicts, lists protections for persons not taking part in the conflict. It is phrased broad yet vaguely enough for Israel to argue that it is conforming to it, and the same goes for customary IHL. More evidence is needed, for example, to judge whether Israel is following the principles of precaution, distinction, and proportionality in its current air campaign on Gaza. Yet, by declaring a full blockade of Gaza, Israel is likely making itself culpable for IHL violations by using starvation as a means of warfare and impeding upon humanitarian relief efforts. The statements by the Israeli defense minister make it plain that Israel is attempting to starve out Gaza. The question of who could bring such a claim before an international court, however, remains (see here).


This article tried to answer the questions whether Israel had a legitimate right to invoke self-defense and whether it was following the law of war  from a legal perspective; any moral considerations warrant another piece. What is clear, however, is that, regardless of which way you spin it, Israel has the right to defend itself against Hamas. Either through self-defense against a NSA, through self-defense against a state, or through a domestic military operation. Yet, Israel’s actions and rhetoric thus far point to IHL violations being committed that will have severe impacts on the civilian population. Another piece is necessary to examine how such violations, if possible, can be prosecuted.

Other posts that may interest you:

One Comment

  • Regina says:

    It is quite an insightful piece, Linn. It introduces readers to the legal complexity of the subject in an approachable way.