The Constructive Ambiguity of the Security Council’s ISIS Resolution

Cross-posted from EJIL:Talk!


On Friday, the UN Security Council unanimously adopted resolution 2249 (2015), condemning a series of recent terrorist attacks by Islamic State (IS, ISIS or ISIL). The text of the resolution, together with statements of Council members, is available here. This resolution was proposed by France and superseded two competing earlier drafts by Russia. The resolution determines that IS constitutes “a global and unprecedented threat to international peace and security.”

But the resolution itself is, perhaps, an equally unprecedented measure by the Security Council. The resolution is clearly designed to provide legitimacy for the measures being taken, and to be taken, against IS by giving the Council’s imprimatur to such measures. In particular, the resolution is worded so as to suggest there is Security Council support for the use of force against IS. However, though the resolution, and the unanimity with which it was adopted, might confer a degree of legitimacy on actions against IS, the resolution does not actually authorize any actions against IS, nor does it provide a legal basis for the use of force against IS either in Syria or in Iraq.

The main operative paragraph of the resolution is para 5, in which the Council:

“5.   Calls upon Member States that have the capacity to do so to take all necessary measures, in compliance with international law, in particular with the United Nations Charter, as well as international human rights, refugee and humanitarian law, on the territory under the control of ISIL also known as Da’esh, in Syria and Iraq, to redouble and coordinate their efforts to prevent and suppress terrorist acts committed specifically by ISIL also known as Da’esh as well as ANF, and all other individuals, groups, undertakings, and entities associated with Al-Qaida, and other terrorist groups, as designated by the United Nations Security Council, and as may further be agreed by the International Syria Support Group (ISSG) and endorsed by the UN Security Council, pursuant to the statement of the International Syria Support Group (ISSG) of 14 November, and to eradicate the safe haven they have established over significant parts of Iraq and Syria;”

Before we attempt to decipher what this paragraph actually means, it is important to note that the resolution was not adopted under Chapter VII of the Charter. Or rather, the resolution does not use the “acting under Chapter VII” formula that is usually used to signal that the Security Council intends to take binding action, despite a couple of determinations in the preambular paragraphs about the existence of a threat to international peace and security, which (determinations) presumably are made under Article 39 of the Charter. In op. para. 1 of the resolution, the Council similarly “regards all such acts of [IS] terrorism as a threat to peace and security,” which again implicitly invokes Article 39. As the ICJ’s Namibia Advisory Opinion makes clear, the lack of reference to Chapter VII in a resolution does not mean that it is not to be regarded as binding nor does it mean that the resolution does not have operative legal effect. However, for the resolution to have those effects the Council must actually decideto do something or to authorize something.

What is particularly significant about Resolution 2249 is that it calls upon states to “take all necessary measures” (or more commonly “all necessary means”). As is well known, the expression “all necessary measures/means” when used in Security Council resolutions is code for the use of force. (For a rigorous overview of the Council’s practice in adopting Chapter VII resolutions, see this 2008 research paper at Security Council Report).

However, in this case, the Council does not authorize “all necessary measures,” nor does itdecide that they be taken, but rather “calls upon” states to take such measures. This difference in language itself suggests that though the Council contemplates, and perhaps would even welcome, the use of force by states, it does not authorize such action. This lack of authorization is made clearer from the fact that the resolution calls for all necessary measures, “in compliance with international law, in particular the United Nations Charter”. This wording suggests that measures taken should comply with other rules of international law, including the jus ad bellum rules in the Charter. Thus, the resolution is to be seen as only encouraging states to do what they can already do under other rules of international law. It neither adds to, nor subtracts from, whatever existing authority states already have.

The use of the “all necessary measures” formula in an operative paragraph of a Council resolution which does not contain a decision appears to be novel. Its closest equivalent could be the rather dated resolution 221 (1966) which in its op. para. 5 “called upon” the UK government “to prevent, by the use of force if necessary,” of tankers bringing oil to Southern Rhodesia.

Similarly novel is the use of the “all necessary measures” formula in a resolution that does not state that it is adopted “acting under Chapter VII.” The closest equivalent to this formulation that we could find is resolution 2213 (2015), in which the Council expressed grave concern about terrorist groups in Libya proclaiming allegiance to IS and “reaffirm[s] the need to combat by all means, in accordance with the Charter of the United Nations and international law including applicable international human rights, refugee and humanitarian law, threats to international peace and security caused by terrorist acts”. Although that resolution was adopted under Chapter VII, it speaks of “all means” rather than “all necessary means”, and more importantly, the text just quoted was in a preambular paragraph, thus making it clearer that the Council was not authorizing anything, let alone the use of force.

Resolution 2249 is not the first time that a Security Council resolution has referenced the right of states to use force without itself authorizing such a use of force. Perhaps the best and clearest examples of such a referencing are resolutions 1368 and 1373 (2001) which reaffirm the inherent right of individual and collective self-defence after the 9/11 attacks. Those resolutions did not authorize US and allied actions in Afghanistan, but gave a Security Council stamp of legitimacy to them. Yet in those  post 9/11 resolutions the support was expressed in the preambular paragraphs and not in an operative paragraph. And it is clear what legal argument the Council or members of the Council were supporting with respect to Afghanistan – a self defence argument – even if the exact legal theory behind that argument remained contested and unclear.

Resolution 2249, on the other hand, is constructed in such a way that it can be used to provide political support for military action, without actually endorsing any particular legal theory on which such action can be based or providing legal authority from the Council itself. The creative ambiguity in this resolution lies not only in the fact that it does not legally endorse military action, while appearing to give Council support to action being taken, but also that it allows for continuing disagreement as to the legality of those actions.

Many states are already taking action against ISIS in Syria and Iraq, but they have different legal bases for doing so. The US-led coalition relies on consent with regard to action taken within Iraq, and the collective self defence of Iraq with regard to action taken in Syria. But the US, the UK and perhaps France (see here, here and the wonderfully ambiguous French letter to the Council in S/2015/745) have also made reference to individual self-defence with regard to strikes in Syria. Russia for its part (and presumably Iran) would rely on consent from the Syrian government with regard to their action in Syria, and like Syria regard actions taken by Western states in Syria without the consent of the Syrian government to be unlawful.

The US-led coalition will no doubt claim that resolution 2249 implicitly validates or confirms the legality of their current actions. In the UK, the Prime Minister is already using the resolution to build support for a decision to join the military action in Syria and it would not be a surprise to see the resolution used in response to concerns expressed about the legality of UK action in Syria. However, the resolution is also worded in such a way that it equally allows Russia, Syria and others to insist that the use of force in Syria without consent of the Syrian government is unlawful. This, therefore, is the resolution’s constructive ambiguity: it allows the major players in Syria to politically move closer together without departing from the legal positions that they had previously adopted, and without compromising their essential interests.

Two other minor points may be noted about resolution 2249. First, although the resolution speaks of “all necessary measures . . . on the territory under the control of ISIL also known as Da’esh”, it is not clear precisely what the necessary measures are supposed to be directed at. The single sentence in the paragraph is so long and convoluted that the objective that the measures are meant to achieve is not easy to decipher. It appears that states are called upon to take all necessary measures are to (i) redouble and coordinate their efforts to prevent and suppress terrorist acts committed by ISIL and others, and (ii) eradicate the safe haven they have established in Iraq and Syria.

Another point of note is that the resolution calls on states to take all necessary measures in compliance with international human rights law as well as international humanitarian law (and refugee law). This is standard language in relation to counter terrorism measures not involving the use of force (see, e.g., resolutions 2213 and 2214 (2015), Libya). However, here there is a call for a use of force but there is still a reference to international human rights law (IHRL). Although this may not have been the intention of the drafters, the fact the resolution covers and was intended to cover the use of force extraterritorially, but still included a call for compliance with IHRL, could be used as evidence that the even the Security Council has endorsed the view that IHRL does indeed apply to extraterritorial uses of force by states.


Dr Marko Milanovic is associate professor at the University of Nottingham School of Law. He is co-editor of EJIL:Talk! and a member of the EJIL’s Editorial Board, as well as Secretary-General and member of the Executive Board of the European Society of International Law.