The Legality Surrounding the US Strikes in Syria

by Nancy Simons

[Nancy Simons is a Belgian lawyer and serves on the International Bar Association’s Drones Task Force. Her professional background lies in international law generally. She has worked at a number of international non-governmental organisations and the International Criminal Tribunal for the former Yugoslavia.]

It has been almost two weeks since the United States (US) initiated several missile strikes on a Syrian airfield. From the US perspective, the justification for this use of force was that it was in response to the use of chemical weapons allegedly by the Assad regime. The use of these prohibited weapons on the Syrian population resulted in the death of dozens of civilians and left many more injured. There has been much discussion surrounding this attack (see, for example, here, here, here and here). There are also many different legal and political factors attached to this situation, some of which have yet to come to fruition. These include, inter alia, the absence of US Congress approval, the outcome of the investigation into the use of chemical weapons, and how to justify and reconcile the US strikes with the United Nations (UN) Charter and the general prohibition on the use of force under international law. This post will focus on this last matter. Before delving into some of the key legal issues, it should be noted that the US strikes contrast with the position previously adopted by the US, whereby it directed its military force towards the fight against the so-called Islamic State of Iraq and the Levant (ISIL) under its umbrella of ‘the war on terror’ on the basis of self-defence, as opposed to directing such attacks toward the Syrian regime. The question here is what is the legal basis for these attacks against a sovereign state? The US strikes have been supported by numerous states, such as the United Kingdom (UK), Australia, Israel, and Turkey. However, the US has yet to come up with a clear legal foundation justifying this attack.

Legal justifications?

International law, through the lens of the UN Charter, only allows for two exceptions to the prohibition on the use of force, as expressed in Article 2(4) of the United Nations Charter. The first exception is the system of collective security under Chapter VII of the Charter, whereby the UN Security Council (UNSC), after having made a determination of the existence of a threat to international peace and security, authorises states to take military action. However, although several UNSC resolutions condemn the use of chemical weapons (see here, here and here), the UNSC has not used any language in these resolutions that could legally justify the US strikes. UNSC resolution 2209 (2015), para.7 decides that in the event of further violations to the prohibition of the use of force, the UNSC would be ready to undertake further actions under Chapter VII, thus potentially opening the door to the use of force. A further resolution is thus necessary to authorise the use of force under chapter VII, which has not been adopted so far.

The second exception is self-defence, as materialised in Article 51 of the Charter, which provides that states have the right to use military force in response to an armed attack. With respect to the current situation, the US Strikes targeted Syrian territory with no impact on US territory or sovereignty, thereby excluding self-defence as a possible justification.

It is possible (but unlikely in my view) that a third exception exists, which has been argued stems from customary international law: humanitarian intervention, which would allow States to intervene in the event of ‘gross and systematic violations of human rights’ as a last resort. The Charter only allows for two exceptions (as discussed above), and searching for an exception outside the Charter is a challenging path considering the importance of the prohibition enshrined in Article 2(4). However, as States are reluctant to use this exception as a justification for their military actions, it is heretofore difficult to argue that the principle is a legal one. As a matter of law, humanitarian intervention is not part of customary international, but depending on the reactions of States to situations such as the US strikes against Syria, this principle could one day become an exception to article 2(4). It is true that the use of chemical weapons certainly qualifies as a gross violation of human rights, which arguably triggers the right to invoke humanitarian intervention in response to such an act, assuming of course such a principle is a rule of international law. However, unless part of a broader strategy aimed at protecting the civilians from further atrocities, it is difficult to understand how the attack of 7 April 2017 satisfies such a purpose, rather than just being a punitive and deterrent act in reaction to the use of chemical weapons. The statement made by Trump (‘It is in this vital national security interest of the United States to prevent and deter the spread and use of deadly chemical weapons’), further highlights that humanitarian intervention would be a questionable basis for the use of force exercised in this case. On the other hand, the United States has also shown its readiness to use force in the event of further attacks on civilians, not just through chemical weapons, but also regarding barrel bombs, perhaps denoting humanitarian concern.

One must also acknowledge that states have increasingly construed the exceptions to the prohibition on the use of force in innovative ways, such as the self-defence against non-state actors – a position adopted by many states in the fight against ISIL. However, there is no similar argument to be made in this case. This begs the question as to whether some states consider the prohibition on the use of chemical weapons, which now forms part of the rules of customary international law, to be so imperative that it warrants a breach of the prohibition on the use of force, which is a cornerstone of the UN Charter. The fact that the use of chemical weapons is prohibited does not provide a legal avenue for states to resort to force as a basis for intervention, unless an exception was established, which is currently not the case.

The only conclusion from an international law standpoint is that the missile attack that occurred on the Syrian airfield is illegal. Does this mean that it is acceptable (not legal) to act outside the framework of the UN Charter when deemed necessary or when pursuing a ‘legitimate aim’? States’ reactions supporting the attack are formulated in non-legal terms, which denote a political understanding for this course of action chosen by the US in the face of the crimes committed, rather than legal approval. It is not the first time that the prohibition on the use of force has been violated and not sanctioned by the international community. However, this should not necessarily mean that the legitimacy of the UN Charter is diminished. This case does perhaps highlight the limits of international law and its inexorable tie to international relations, a clear reason why the UNSC is blocked and thus unable to take legal action, as the deadlock stems from the political nature of this organ and the UN system as a whole. The risk that such action creates is that although the attack may be seen as morally or ethically legitimate, acting outside the purview of the law means that legal requirements are not to be respected. This dangerously opens the door to using force under possible false pretences. Of course, the same false pretences could be pursued within the boundaries of the legal framework, but at least the law acts as a barrier in limiting the recourse to force in such situations.

Potential legal consequences?

Despite the current absence of sanction (and quite the opposite, the support of the attack), the strike may not come without legal consequences. The first consequence is hypothetical and unlikely to occur at this time. Having suffered an armed attack, Syria is entitled to exercise its inherent right to self-defence (along with allies if asks for help). This hypothetical would be an unlikely (but possible) outcome for two key reasons. Firstly, the political picture with the powers at force is not in favour of such a response. Secondly, the lapse of time between the attack and the response along with the limited impact of the attack would prove difficult to ascertain that the actions taken pursuant to the right of self-defence are necessary and proportionate. The second potential consequence relates to the law applicable to the conflict that is affecting Syria. Until today, there was a conflict between ISIL and the Assad regime together with a conflict between the US (and the international coalition) and ISIL, which both, it is generally accepted, qualify as non-international armed conflicts (NIAC). This first attack from the US could change this picture. The ICRC has not hesitated to advance that there is now an international armed conflict (IAC) between the US and Syria, meaning that a different and more extensive set of rules apply. Depending on the position adopted, this could lead to either the internationalization of the conflict in Syria, meaning that there would be an IAC between all the actors (including ISIL) or that there would be a situation of mixed conflicts, IAC between the US and Syria and a NIAC for all the other actors, which in turn would lead to different applicable rules.  It remains to be seen how this will materialize.

6 Responses

  1. Side question:

    Is the US engaged in an armed conflict with Russia? If the US is engaged in an IAC with Syria, and Russia is a co-belligerent of Syria, does that entail that the US is engaged in an armed conflict with Russia?

  2. Thank you for your question. This is an interesting and tricky one.

    Assuming that there is an IAC between Syria and the United States, I don’t think that we can automatically infer from that that the US would be engaged in an armed conflict with Russia based on a co-belligerency theory.

    The way I see this hypothetical is that Russia is fighting alongside the Assad government, but Russian support is, so far, restricted to the fight against ISIL. An argument could be made that although Russia is fighting side-by-side with Syria, they would be involved in separate armed conflicts, pursuing separate purposes. However, considering the political support provided by Russia to Syria in the aftermath of the US strikes, the situation could change in the event of further US military actions against Syria. Another point to consider would be whether Russia was to make any statements regarding neutrality.

    Regarding the question of whether the US is engaged in an armed conflict with Russia, if the latter is a co-belligerent to Syria, I think that a distinction should probably be drawn between ius in bello and ius ad bellum, in the sense that considering Russia as a co-belligerent would qualify it as a possible target. However, as long as no force is being used against Russia by the US, and Russian support to Syria does not amount to a factual contribution that could be construed as assigning “co-belligerent” status, the US would not be engaged in an armed conflict with Russia.

    With this said, I would be really interested in learning more about how the inverse of this point could be put forward from an international law perspective.

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