The Use of Force against ISIL in Libya and the Sounds of Silence

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As acknowledged by the UN Security Council in Resolution 2249 (2015), ISIL constitutes ‘a global and unprecedented threat to international peace and security’. At least in part, the unprecedented nature of this threat can be attributed to the fact that, in addition to the swathes of territory held in Iraq and Syria, ISIL maintains a presence in various other states, including Libya, Afghanistan, Egypt, Tunisia and Nigeria. Consequently, it was only a matter of time before states started considering striking these other states.

On 13 November, the US made the first move in expanding operations beyond Iraq and Syria, conducting the first airstrike by a Western state specifically targeting ISIL within Libya. It has now been confirmed that the successful strike killed Abu Nabil, the US-dubbed ‘leader’ of ISIL in Libya. Little has been said regarding the airstrike by states or legal commentators, though this is understandable in a period where the world is coming to terms with the devastating terrorist attacks in Paris, Mali, Nigeria, Tunisia and Egypt. However, reflecting back on the strike, questions surround its legality. This post will focus on legality under jus ad bellum, while acknowledging that an airstrike directly targeted at an individual may also trigger international humanitarian law and human rights law.

Prior to assessing the legality of the strike, it is important to consider what we actually know about the strike. In announcing the strike against Abu Nabil, the US Pentagon Press Secretary stated that:

‘On November 13, the U.S. military conducted an airstrike in Libya against Abu Nabil, aka Wissam Najm Abd Zayd al Zubaydi, an Iraqi national who was a longtime al Qaeda operative and the senior ISIL leader in Libya.

Reporting suggests he may also have been the spokesman in the February 2015 Coptic Christian execution video. Nabil’s death will degrade ISIL’s ability to meet the group’s objectives in Libya, including recruiting new ISIL members, establishing bases in Libya, and planning external attacks on the United States.

While not the first U.S. strike against terrorists in Libya, this is the first U.S. strike against an ISIL leader in Libya and it demonstrates we will go after ISIL leaders wherever they operate.

We will provide additional information as and when appropriate. This operation was authorized and initiated prior to the terrorist attack in Paris.’

Notably, the statement provides no explicit legal justification for the strike. This silence has not been remedied since, leaving us to perform the risky task of reading between the lines of the Pentagon statement, while searching for a possible legal justification for this prima facie breach of Article 2(4) UN Charter.

Under the generally accepted formulation of self-defence in international law, whether relying on Article 51 UN Charter or the customary right existing in parallel, a state must establish that its use of force was in response to an armed attack, or in order to avert an imminent armed attack, as well as being both necessary and proportionate.

Assuming that self-defence can be invoked against attacks by non-state actors unattributable to the territorial state, the key question with regards to the Abu Nabil strike is whether the use of force was in response to an armed attack, or in order to avert an imminent armed attack.

Paragraph 2 of the Pentagon statement might suggest that the US consider the airstrike as both a response to the February 2015 executions of Coptic Christians in Libya, and/or as a measure to avert future attacks by ISIL in Libya.

The former justification faces a number of difficulties. First, while a tragic and horrific act, it is highly unlikely that the executions would surpass the threshold to be regarded as an ‘armed attack’. If the executions were an ‘armed attack’, the contemporaneous SC Res 2214 (2015) arguably would have identified the incident as engaging the right to self-defence, similarly to SC Res 1368 (2001). Second, as the executions were reportedly against Egyptian nationals, the US is precluded from claiming that it was the victim of the armed attack. Only a request from the Egyptian Government for assistance in exercising their right of self-defence (i.e. collective self-defence) would permit US intervention. Third, an airstrike conducted 9 months after the executions would ignore the inherent temporal limits of self-defence, and therefore constitute an unlawful armed reprisal.

The latter justification, namely to avert future attacks by ISIL in Libya by degrading their planning capabilities, is equally untenable, stretching the concept of an imminent armed attack to breaking point and venturing into the unlawful realm of pre-emptive self-defence.

Additionally, there are difficulties should the US claim (as they have with Syria) that airstrikes are justified on the basis that Libya is ‘unwilling or unable’ to prevent armed attacks emanating from their territory. Whether or not such a label is factually accurate, with the civil war in Libya perhaps suggesting inability, the legal status of the phrase itself in questionable. Recent invocations of ‘unwilling or unable’ in the context of Syria by the US, UK, Canada, Australia and Turkey have utilised the term as part of the law of self-defence, seemingly arguing that the necessity criterion is fulfilled where a territorial state is ‘unwilling or unable’ to prevent otherwise un-attributable armed attacks by non-state actors emanating from its territory. However, this practice is by no means conclusive.

Where the Security Council identifies a threat to the peace, breach of the peace, or act of aggression (Article 39 UN Charter), it may, inter alia, authorise forcible measures against a state (Article 42 UN Charter).

While the final paragraph of the Pentagon statement states that the operation was ‘authorised’, this likely speaks to authorisation under domestic law, pursuant to the Authorisation for the Use of Military Force (AUMF). Whether the US could point to a specific Security Council authorisation rests on two possible arguments:

1) The airstrike was authorised by SC Res 2214 (2015) on Libya and counter-terrorism; and/or

2) The airstrike was authorised ex post facto by SC Res 2249 (2015).

With regards to 1), in Resolution 2214 (2015) the Security Council, inter alia:

‘urge[d] Member States to combat by all means, in accordance with the Charter of the United Nations and International Law, threats to international peace and security caused by terrorist acts, including those committed by ISIL [and associated groups]’ (Operative Paragraph 3).

However, despite the phrasing ‘combat by all means’, it is unlikely that SC Res 2214 (2015) can be said to provide an authorisation for states to use force in Libya.

In addition to the (perhaps formalistic) fact that the Resolution does not bear the customary hallmarks of authorisation, namely the language of ‘acting under Chapter VII of the Charter of the United Nations’ and ‘all necessary measures’, the phrase that comes closest to providing authorisation for forcible action (‘combat by all means’) is directly followed by emphasis that all measures taken should be in conformity with the Charter of the United Nations and other international obligations. This could be read as the Security Council reminding states that authorisation is not carte blanche; intervening states are still subject to their other international legal obligations. However, the reference to the UN Charter sits uneasy. If force is authorised, what further obligations under the UN Charter could be at risk of breach?

With regards to 2), this post will not rehash the arguments, typified in the excellent posts by Weller and Akande and Milanovic, as to whether SC Res 2249 (2015) authorises forcible action in Syria and Iraq, but instead notes that, in any case, such an authorisation would not likely extend to Libya. While ‘reaffirming that terrorism in all forms and manifestations constitutes one of the most serious threats to international peace and security… whenever and by whomsoever committed’ (preambular paragraph 5), the Resolution and the Verbatim Record simply do not mention Libya. It cannot be presumed that any authorisation extends to a third, unnamed state; such an infringement of sovereignty must be based on an express intention.

A state may consent to force being used on its territory. Assuming that any consent was provided by the internationally recognised and democratically-elected ‘Tobruk Government’, noting the ongoing civil war in Libya, and that the airstrike was aimed specifically at ISIL and not either party to the civil war, the issue turns on whether the US received consent to use force in Libya, extending to the specific airstrike in question.

While it is reported that a previous airstrike against Al-Qaeda in Libya was conducted by the US in June 2015 with consent, there has been no mention of consent with regards to this latest strike.

In the Armed Activities case, the ICJ found that consent continues until withdrawn, therefore the presence of Ugandan troops following the withdrawal of DRC consent was unlawful. Notably, it was held that there are no formalities required for the withdrawal of consent (para 47), and that consent may be circumscribed to fulfilling certain tasks (para 52).

Consequently, the US would have to show that the consent acquired for the June 2015 strike was expressed broadly enough to connote an ongoing authorisation to conduct airstrikes against terrorist targets until such consent is withdrawn, as opposed to specifically for that strike.

While consent is not mentioned in any publicly available documents, one could look towards SC Res 2214 (2015), in which the Security Council:

‘Expresse[d] strong support for the efforts of the Libyan Government to combat ISIL [and associated groups], and of members of the international community assisting the Libyan Government in this regard upon its request;’ [emphasis added]

However, a further question remains as to whether the assistance provided extends to military force.

Finally, a question remains as to whether an established legal basis for striking ISIL in Iraq or Syria might further justify force against ISIL in other states. Such an argument might be discerned from paragraph 3 of the Pentagon statement, specifying the US’ commitment to ‘go after ISIL leaders wherever they operate’.

The fundamental difficulty of such an argument is that it ignores the fact that the rules of jus ad bellum are state-centric, granting primacy to traditional notions of state sovereignty and territorial integrity. Consequently, arguments proposing a ‘global war on terror’ or a ‘global war against ISIL’ fail to recognise that each possible legal justification for using force is spatially limited to a particular state.

First, with regards to self-defence, it might be argued that the increasing acceptance that states can forcibly respond to unattributable ‘armed attacks’ by non-state actors on the territory of an innocent state reflects a willingness to subordinate concerns of sovereignty to combatting terrorism. However, it is an entirely different matter to say that there is a ‘global right of self-defence’ decoupled from the particular state’s territory from which an armed attack is, or is soon to be, launched. There is simply no state practice or opinio juris to support such a contention. Secondly, as argued above, Security Council authorisation cannot be presumed to extend beyond the state specifically addressed in the relevant Resolution. Finally, a state would be acting ultra vires if it purported to provide consent extending to the territory of another sovereign state.

In conclusion, consent provides the strongest possible justification for the US, noting previous cooperation with Libya. Additionally, consent provides a simpler route to legality than wading through the legal uncertainties of Chapter VII UN Charter authorisation and self-defence; a simple yes/no from the Libyan government to confirm would be sufficient. However, the paucity of publicly available information regarding the strike leaves us searching for a legal justification between the lines, resulting in strained interpretations of official statements and legal uncertainty. While unfettered and complete transparency is a dangerous aim, silence on such important issues pushes the international rule of law to the background.

Beyond the difficulties of interpreting the sounds of silence, a final point remains. While terrorist organisations are not bound by the rules on inter-state force, regularly seeping across new borders and capturing territory, states contributing to the forcible efforts are so bound. While Western leaders may wish to eradicate ISIL by striking all states in which ISIL presence is confirmed, they are restrained by international law and its central organising principle: Sovereignty.

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Kriangsak Kittichaisaree says

January 6, 2016

Many good points.

However, the sounds of silence might result from the uncertainty in the minds of the majority of States as to how to deal with the unprecedented phenomenon of ISIL under existing customary IL and the UN Charter. As apparent in the various debates at this EJIL Talk!, many legal scholars interpret the applicable rules of IL differently in the ISIL context. Against this backdrop, legal advisers of the nations actively using force against ISIL may be excused for adopting the posture of 'a man [who] hears what he wants to hear and disregards the rest'. Vague official statements help avoid the need to elaborate legal bases, while the goal of suppressing ISIL is pursued.

Could (or would it be desirable for) the international community of nations (to) sit down to authoritatively determine how best to eliminate ISIL under IL and without creating adverse consequences on the future of IL (in the sense of opening a Pandora's box that would undermine international peace and security)? Of course, existing law must be respected unless and until replaced by new law. Has this already occurred re: ISIL is a question that needs to be answered.

Jake Rylatt says

January 8, 2016

Dear Kriangsak,

Thank you for your thought-provoking response.

I agree that, as a matter of fact, official statements can be phrased vaguely to avoid providing legal bases while pursuing the goal of suppressing ISIL, but I would strongly challenge the desirability of adopting such an approach. I greatly doubt many would challenge the upmost importance of suppressing ISIL, but, as you note in your second paragraph, existing law must be respected in pursuing this goal. How are we really to know whether existing law has been respected without an official justification for the airstrike? We can look at the factual pattern and attempt to discern a justification, as I have attempted to do in this piece, but a great deal of uncertainty remains. Now this is not to say that the provision of a legal justification by a state automatically provides complete clarity as to whether a use of force is in conformity with international law, since the interpretation of the jus ad bellum is open to reasonable disagreement (as EJIL: Talk! regularly reflects). However, enunciating a purported legal basis for the airstrike would greatly assist in narrowing the task while providing a layer of transparency that supports the maintenance of the international rule of law.

I also think there is another important issue arising from the silence, and it ties into your question regarding whether any new rules of international law have emerged regarding ISIL. This is the question of the extent to which we can take into account the strike in Libya as evidence of the development of international law. For example, the question arises as to whether the US considered that they were entitled to strike ISIL targets in Libya because the right to self-defence can now be utilised against a non-state armed group in every location they operate, regardless of territorial boundaries? If they did, and enunciated that in an official statement, we can point to one instance of both state practice and opinio juris (though only one) in favour of such an interpretation of the right to self-defence. However, as it presently stands, even if they did hold such a belief (i.e. the opinio juris element), we have no evidence; it could just have easily been a case where the Libyan government provided consent. Consequently, the provision of a legal justification would be beneficial in not only considering whether existing law has been respected, but whether the responses of states to ISIL are contributing to the creation of new rules or interpretations of international law.

Finally, my difficulty with the idea of the international community (by this I would assume you mean a full forum of states such as the UNGA as opposed to the UNSC?) meeting to authoritatively determine how best to eliminate ISIL under international law is identifying an actual concrete outcome. What do you envisage as the end result? Would the result be merely strategic, or an attempt to modify international law in some form? Also, I am interested by what you consider might constitute the possible Pandora’s Box in this scenario? What adverse consequences on the future of international law are in your contemplation?

Best wishes,


Kriangsak Kittichaisaree says

January 9, 2016

Dear Jake,

I would say that the 'sounds of silence' serves the strategic goal of the States using force against ISIL. I raise the possibility of having the UNGA (as opposed to the UNSC)or a high-level international meeting to allow the 'silent majority' to speak out how IL can be resorted to to eleminate ISIL without undermining the customary IL principles of sovereignty, territorial integrity, etc. The UNGA might even request an advisory opinion from the ICJ on the points raised by you.

Witout such a meeting, the States using force against ISIL might be able to reply on the argument that they are 'specially affected States' and that their action constitutes (or is crystallizing into) a new rule of CIL (while the States in whose territories the use of force against ISIL have taken place are more or less silent/mute in their reactions). Recall the Dis. Op. of Judge Lachs in the North Sea Continental Shelf Cases in 1969: "To give a concrete example: the first instruments that man sent into outer space traversed the airspace of States and circled above them in outer space, yet the launching States sought no permission, nor did the
other States protest. This is how the freedom of movement into outer space, and in it, came to be established and recognized as law within a remarkably short period of time. Similar developments are affecting, or
may affect, other branches of international law."

Heiko says

March 3, 2016

Is ISIS really something new? it started as Saddam 2.0 and avoided all the mistakes Saddam 10 had made. It added the idea of Umma. "You have to make the war bigger", Clausewitz in War and Peace. And when we compare ISIS with the 20.000 corpses of the Bani Sadr armee even that ius not new. Yes, yes, no, no is the rule of that region. And Western Sahara comes to mind. Thanks!!