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  • Writer's pictureVedant Das

Understanding the Emerging Custom of Using Force against Non-State Actors

Updated: Apr 14, 2022

What if there is an "armed attack" from an independent non-state actor who isn't an agent of the state?


After capturing Mosul in 2014, the forces of the Islamic State of Iraq and Syria (hereafter ISIS) attacked several towns in the Sinjar area, which was populated by a Kurdish minority known as Yazidis. After causing the gravest of human rights violations, some 40,000 Yazidis took Refuge in Mount Sinjar. The ISIS forces had cut all their means to egress from mount Sinjar. The Yazidis were now stuck on a 40,000 meters tall mountain. Seeing this human catastrophe unfold, President Obama authorized airstrikes against the ISIS forces.

According to various United Nations reports that emerged after the massacre, it was estimated that more than 5000 people, mostly men, were killed. August 3 2014, was no ordinary day for the international community; that day marked a turning point in Iraq's political trajectory. ISIS prompted a mass exodus and a political crisis unprecedented in recent history; however, the question that arises is whether using force against a non-state actor such as ISIS was legal?

Self-defense is a part of Customary International Law and has been codified in the UN Charter under Article 51. The text of the said article clearly states that nothing in the Charter shall impair individual or collective self-defense if an armed attack occurs against a member state.

As with numerous other loopholes in the United Nations charter, this one also exists– nowhere in the Charter is the term "Armed Attack" defined. The definition of an "Armed Attack" was laid down by the International Court of Justice (hereafter ICJ) in the case of Nicaragua vs USA Thus, the court established the following facts: first, before a victim state can use force, the territorial state must exert effective control over the non-state actors, i.e., the non-state actors must serve as agents of the state. Secondly, since there is no definition of an "armed attack" provided by the UN Charter, the court stated that the gravest forms of attacks allow states to invoke Article 51. Thus, even the smallest string of attacks can aggravate or constitute an armed attack. An important point to be noted here is that such attacks don't include "mere frontier incidents". Lastly, for any victim state to invoke Article 51 against a non-state actor, the said non-state actor should be attributed to the state, i.e., it should act as an agent of the state.

Now, here arise two critical questions in front of the International Community:–

What if there is an "armed attack" from an independent non-state actor who isn't an agent of the state?

Furthermore, what if the "attack" conducted by the non-state actor in question reaches the threshold of a "Grave attack" as laid down by the ICJ?

During the Congo case in the ICJ, Judge Koojimans highlighted that during the era of Al-Qaeda, it was "unreasonable to deny the attacked State the right to self-defense merely because there is no attacker State".

Similarly, Judge Simma concluded in his separate opinion on the Congo case stated that "Security Council resolutions 1368 (2001) and 1373 (2001) cannot but be read as affirmations of the view that large-scale attacks by non-State actors can qualify as 'armed attacks' within the meaning of Article 51."

Additionally, how can one be completely sure that a non-state actor is acting as the agent of the state? If we take the example of Al-Qaeda bombing the twin towers, one can easily conclude that Al-Qaeda acted independently, and the Taliban did not endorse the action. Taliban officials emphasized the fact that Osama bin Laden was innocent and had nothing to do with the attacks. Even if Al-Qaeda did act on its discretion and the member states endorsed the actions, one can say that there has been a shift in state practice on the use of force against non-state actors, and this was reaffirmed by the positive reaction to Operation Enduring freedom.

This emerging norm in International Law was on the path to crystallization when the US authorized attacks against ISIS in Syria. Technically, by doing so, the US violated Syria's sovereignty and its territorial integrity.

Going by the official statement from the US for attacking Syria, it was specifically highlighted that Iraq was facing an imminent threat from ISIS and that Syria was used as a haven. Since the Syrian regime was incompetent to combat these safe havens, the United States of America had a right to self-defense and help Iraq who had consented to the involvement of the US in its fight against ISIS

Being a common enemy, the Syrian regime protested against the same but, eventually, acquiesced in. Since there was no further protest by any other member state either, this emerging norm successfully got on its way to crystallization.

The crystallization of this norm was almost inevitable. In 2015, after the bombing of a Russian jetliner over the Sinai desert and ISIS attacks on a Paris stadium and concert hall on October 31 and November 13 respectively, the UN Security Council unanimously adopted Resolution 2249, which determined that ISIS is "a global and unprecedented threat to international peace and security," and called for "all necessary measures" to "eradicate the haven [ISIS] established". In Syria, however, the issue was that the wording of resolution of 2249 was very ambiguous because, as established by the ICJ in the case of Namibia vs South Africa , the binding nature of a Security Council resolution is determined by the nature of language and the terms used.

Thus, neither was resolution 2249 adopted under Chapter VII of the UN Charter nor did resolution 2249 authorize article 42, which is the same article and chapter under which the Security Council can permit states to use force as an exception to Article 2(4) of the UN Charter. The resolution also does not use the words "authorizes" or "decides" in its operative clauses.

International Law seemed to be moving rapidly towards the adoption of the "unable and unwilling" principle of self-defense. But in the Wall and Congo cases of 2004 and 2005 respectively, the ICJ and the relevant Security Council's resolutions reaffirmed that the International Law permits extraterritorial attacks against non-state actors, but only when their actions are attributable to the territorial state, thus, utilizing an effective control standard on the usage of force by non-state actors.

In a very technical sense using force against an entity like ISIS was a violation of International law however one can conclude from the positive reaction received from the International Community by the US when it resorted to force against Al-Qaeda in Afghanistan (keeping in mind there was no proper proof that al-Qaeda was attributed to Taliban), and against ISIS in Iraq and Syria, a norm was established for the use of force against independent non-state actors.

However, the ICJ has turned a blind eye to this emerging norm in the coming years and has effectively left it on state interpretation. This might lead to very dangerous precedence. Hence, the ICJ must recognize this emerging norm in future cases. Despite there being widespread criticism of the ICJ for these holdings, these decisions have unquestionably put a halt to the evolving Customary international law of self-defense against non-state actors.

Vedant has worked with the Centre for Studies in International Relations and Development (CSIRD) on the Syrian conflict. He has won several accolades in numerous conferences.

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