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  • Ahan Gadkari

The Faulty Opinion: The ICJ's ignorance of custom in the advisory opinion on the wall


On 9th July 2004, the International Court of Justice (hereafter ICJ) gave its advisory opinion (hereafter AO) on the Legal Consequences of the Construction of a Wall in the Occupied Palestinian Territory. The advisory opinion was requested by the United Nations General Assembly (hereafter UNGA) in its tenth emergency special session via Resolution ES-10/14. The UNGA has the right to request an AO on a legal question from the ICJ in accordance with Article 96 of the Charter of the United Nations (hereafter UNC), pursuant to Article 65 of the Statute of the ICJ. In the 139th paragraph of the AO, the ICJ stated that Article 51 of the UNC acts as an exception to the prohibition on the use of force in self-defence only when an "armed attack" is launched by one state against another state. Additionally, the ICJ asserted that because Israel does not believe that the attacks on it are the result of a foreign state, their self-defence argument is null and void. To state that the ICJ's assertion is erroneous is an understatement of its invalidity.

The purpose of this article is not to analyze the entire AO but rather to address the ICJ's specific argument regarding the invalidity of self-defence against a non-state actor. Accordingly, this article will take a three-pronged approach to examine the evolution of custom surrounding this subject. To begin, this piece will examine pre-charter customs that established the fundamental right to self-defence. Secondly, it will examine the text of Article 51 of the UNC itself. Lastly, it will study post-charter customs to ascertain if the use of force in self-defence against non-state actors is well established as part of customary international law.

Pre-Charter Custom

Self-defense against non-state actors is a cornerstone of customary international law, and pre-charter state practice demonstrates the same. Even Article 51 of the UNC declares that the right to self-defense is "inherent". Therefore, it becomes apparent that Article 51 did not create a right in that regard but rather acknowledged an existing and fundamental right. This also suggests that the right existed prior to the UNC's creation. The Caroline Affair is the best illustration of an instance that corroborates the preceding argument.

The Carolina Affair was a dispute between the United States of America (hereafter USA) and the United Kingdom (hereafter UK) in the nineteenth century. It was in connection to Canada's territory, which remained under British administration and was undergoing violent resistance. In 1837, the UK sank the Caroline, a vessel used in one of these attacks, when it was in US waters. The contents of the letters exchanged between Daniel Webster, representing the US, and Lord Ashburton, representing the UK, possibly provided the groundwork for the establishment of the law of self-defense. According to Ashburton, the UK's measures were required. While Webster acknowledged the validity of self-defense, he also said that such action should be performed only when no other option existed, and there was no time for contemplation.

In this case, the use of force in self-defense against Canada's resistance, which was a non-state actor, was accepted. The Chatham House principles also support this view. Whereas, opponents of this view claim that this episode occurred prior to the establishment of any norms governing just war, and those states were free to engage in any sort of warfare. However, this argument has a fatal weakness, which stems from the fact that the subject of discussion is custom. Generally, prohibitions and exceptions are based on custom. State practice shapes custom and the Caroline incident demonstrates how the right to self-defense against non-state actors has been ingrained in state practice.

Literal Meaning of Article 51

According to Article 51 of the UNC, each member has the right to self-defense in the event of an armed attack. Article 51 does not categorize armed attacks according to the source of the attack. Article 51 acknowledges explicitly the state's right to respond defensively in the event of an armed attack. Nothing in the text of Article 51 limits the right to self-defense to an armed attack by a state. The words in their ordinary sense must be interpreted to permit self-defense against non-state actors.

The ICJ stated in the AO that because the attack on Israel was not attributed to a state actor, the argument for self-defense under Article 51 does not hold up. The ICJ overlooked that, while the provision does not explicitly mention non-state actors, its terms are obvious - no State nexus is necessary, and no unwritten qualifier is required. Self-defense against non-state actors is permissible simply because armed attacks by non-state actors are still considered armed attacks. This view is endorsed by all three key self-defense policy documents, namely the Chatham House Principles, the Leiden Recommendations, and the Bethlehem Principles. Any other interpretation would be illogical, as it would imply that a state is incapable of defending itself against an armed attack solely because it is not attributable to another state.

Post-Charter Custom

Following the establishment of the United Nations and the UNC's norms, subsequent state behavior appears to support the proposition that states may defend themselves against non-state actors. Recent practice has made a significant contribution to the formation of the law of self-defense, implying acknowledgement of the right to self-defense against both states and non-state actors. The most significant occurrences confirming this were the succession of events that transpired following the 9/11 attacks. Although it should be emphasized that this was not the first case of self-defense being used against non-state actors following the Charter's adoption. In 1998, the United States bombed a pharmaceutical plant in Sudan that was purportedly making nerve gas for Al Qaeda in self-defense following the bombings of the US embassies in Kenya and Tanzania. Nonetheless, the steps taken in the aftermath of 9/11 constituted more than a reinforcement of the right to self-defense against non-state actors.

Following the 9/11 attacks, the US notified the United Nations Security Council (hereafter UNSC) in 2001 that it would be deploying forces in Afghanistan to exercise its right to self-defense. Now, it is a historical reality that the United States entered Afghanistan during Operation Enduring Freedom, which demonstrates unequivocally that unilateral force can be employed against non-state entities in a non-consenting third state as well.

However, it is not just the US military operation in Afghanistan that is regarded to form state practice and contribute to customary international law on this subject. It is critical to highlight the UNSC resolutions adopted immediately afterwards the attacks, specifically resolutions 1368 and 1373. The former (approved the day after the attacks) declares categorically that the UNSC condemns the atrocious terrorist atrocities and views them as a danger to international peace and security. The critical element here is the designation of the act as a terrorist act and the condemnation. The latter compelled states to take a slew of counter-terrorist measures, including criminalization and asset freezing, in order to prevent and combat terrorism. Both resolutions featured a preambular paragraph recognizing the fundamental right to self-defense, either individual or collective, as guaranteed by the Charter. The fact that these resolutions make reference to attacks by non-state actors and in their preambulatory phrases also make reference to and invoke the fundamental right to self-defense is critical. These allusions imply an implicit recognition by the UNSC that unilateral force against non-state actors may be employed in self-defense, even on the territory of a non-consenting third State. Neither resolution contains wording indicating that the initial attack must originate from or be ascribed to a state in order to activate the right to self-defense. It is also critical to highlight that the action was not a UNC’s Chapter 7 authorization to use force but rather a confirmation that the US might utilize its Article 51 right to retaliate with force against a non-state actor.


The purpose of seeking an advisory opinion from the ICJ is to acquire clarity on a particular legal matter. The ICJ has an obligation to consider custom and state practice when issuing its judgments or opinions, as they are believed to establish the jurisprudence around the issue. The ICJ neglected to consider state practice prior to the UNC's creation, contemporary state practice, and the precise wording of Article 51 of the UNC in this AO. Although the ICJ's AO should have established the jurisprudence on the issue, state practice demonstrates the reverse. States continue to defend themselves against non-state actors, and the UNSC affirms these decisions. For example, the US-led coalition's use of force in self-defense against the Islamic State in Syria has been affirmed by the UNSC in its resolution 2249. The fact that state practice continues to encourage self-defense against non-state actors despite the AO demonstrates that the AO could be considered to be a faulty opinion.

Ahan Gadkari is a penultimate law student pursuing the B.A. L.L.B. (Hons.) course in O.P. Jindal Global University. He writes for many think tanks and blogs. His key interests include arbitration and international law.

Image Source: Credits to the Nations

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