President Obama may have temporarily abandoned plans to seek a congressional vote on military action in Syria, but the sentiments of those apprehensive and disillusioned by America’s costly and disingenuous history of intervention are well within earshot. In this piece however, I will leave aside the moral and political questions surrounding intervention. I wish instead to discuss two issues of legality: first, the unlawfulness of the alleged use of chemical weapons and second, that of intervention in Syria.

As a preliminary issue, it bears noting that from the standpoint of international law, (i) use of chemical weapons in the Syrian context is unlawful; (ii) the unlawfulness of the use of chemical weapons does not render a military reaction lawful. The legality (and indeed, illegality in this instance) of intervention and that of deploying chemical weapons are separate questions, which some journalists and politicians seem to conflate in justifying the former.

The customary prohibition on chemical weapons

Assuming the Assad regime was responsible for the attack on 21 August, the question is whether these actions are permitted under international law. Though Assad has agreed to become a party to the Chemical Weapons Convention, Syria’s past conduct would not fall within the Convention as it only applies to acts committed from the date of ratification.

However, any use of chemical weapons on August 21 still falls foul of customary international law. The key pronouncement of this legal position can be found in the Tadić case, where the Appeal Chamber of the International Criminal Tribunal for the former Yugoslavia, held that “there undisputedly emerged a general consensus in the international community on the principle that the use of [chemical] weapons is also prohibited in internal armed conflicts.” This consensus is reflected in the numerous statements, military manuals and national legislations prohibiting such weapons and even arguably the Geneva Gas Protocol and the Chemical Weapons Convention which have 137 and 189 parties respectively. India alone has enacted two statutory safeguards prohibiting weapons which include the nerve gas allegedly used in the August attacks - its Chemical Weapons Act 2000 and Weapons of Mass Destruction and their Delivery Systems (Prohibition of Unlawful Activities) Act 2005.

It is the overwhelming evidence of a customary prohibition on the use of chemical weapons, and indeed the lack of statements to the opposite effect, that create a customary rule applying to non-international armed conflicts like that in Syria. The International Committee of the Red Cross, which has developed a highly regarded study on customary rules in international humanitarian law, supports this position.

Those who question the existence of such a customary rule argue that there is a lack of state practice to support it and point to the arsenals of chemical weapons still held by major states. It is submitted that while countries do stockpile of chemical weapons, almost every allegation of use has been met with strong criticism evidencing an overwhelming consensus that use is illegal. No country holds that the use of such weapons is legal and when confronted by allegations of its use usually denies it as Sudan, Russia and now Syria did.

Therein lies the subjective element of custom - the belief that the practice is accepted as law - and surely denial of breaching a rule speaks volumes of a belief in its existence. Therefore the existence of stockpiles constitutes a violation of the customary prohibition in question, but a breach of a rule does not equate to its non-existence.

Why US military intervention is unlawful

Having ascertained that Syria would have acted unlawfully if it used chemical weapons on its own population, I would like to briefly explain why a military reaction attacking Syrian forces is unlawful within the context of modern, just war discourse.

The prohibition on the use of force by states can be found in Art 2(4) of the UN Charter and customary international law. As many have pointed out, the US cannot rely on Security Council-authorised intervention or self-defence as exceptions to this prohibition. Something can be seen of a justification of collective, pre-emptive self defence reflected in Obama’s language that the failure to respond will “increase the risk of more attacks”. However, there is little evidence of such an exception as the law currently stands and the US itself has not made an express argument of self-defence to this end.

The prevailing pattern in cases of Western intervention in the Middle East - that the traditional derogations to Art 2(4) are not satisfied - applies to Syria. Some have argued that that there is another exception in international law which permits a state to use force in another in order to avoid a large-scale violation of human rights (without Security Council support). The UK in particular has maintained a doctrine of humanitarian intervention subject to three conditions: (i) there is strong and widely-accepted evidence of extreme, large scale humanitarian distress, (ii) there is a lack of a practicable alternative to using force in order to save lives (iii) the proposed use of force is necessary, proportionate and limited in time and scope to the aim of relieving humanitarian need.

This may seem like a convincing test of what the law should be, and indeed would bring the law in line with the moral convictions of several onlookers to the Syrian conflict. However, the problem with the doctrine is that it is far from clear that it has crystallised into customary international law because of the absence of the subjective element described above. A series of cases brought by Serbia (formerly Yugoslavia) before the International Court of Justice showed that only the UK and Belgium were in support of the doctrine of humanitarian intervention in 1999. As previously mentioned, the White House has not sought to argue explicitly for such a doctrine, choosing the threat to its national security instead as its legal justification. So while there is plenty of state practice endorsing intervention on humanitarian grounds, (i) many of these interventions were conducted with a Security Council resolution behind it and (ii) there is insufficient evidence of a belief of lawfulness of such intervention.

The doctrine of Responsibility to Protect (R2P) has not altered this position. R2P started out as a renewed effort to build upon humanitarian intervention and give it legally-binding effect. However, this solidifying process into law was impaired to a large extent by General Assembly Resolution 60/1, which seems to confine R2P to intervention under the auspices of the Security Council.

Alternatives to strikes

Given that both purported acts of Syria and the US are unlawful, it is worth considering what other responses to the unlawful use of chemical weapons the international community can opt for.

One course of action is to bring Syrian nationals allegedly involved in the attacks before the International Criminal Court. Since Syria is not party to the statute of the court, a Security Council referral is needed for the International Criminal Court to have jurisdiction to prosecute members of Assad’s regime for alleged war crimes. Unfortunately, due to the lack of political consensus within the Permanent 5, referral seems unlikely. The situation is further complicated by the fact that the US is not party to the statute either and will have a difficult time convincing Russia and China to seek remedial action against Syria in a legal venue which it itself does not endorse.

Alternatively, there is talk of establishing a Syrian war crimes tribunal, which in any event will probably be pursued by the US if Obama’s agenda falls short at Congress. It is more likely to receive Security Council backing, since the fact-finding role of the tribunal will satisfy the evidentiary doubts that President Putin insists upon.

In the absence of a clear legal recourse in this case, the political and diplomatic process should take the centre stage as it undoubtedly did in the recent G20 summit. If history offers any insights, consensus is of little relevance to the greyhounds on the slips, awaiting war. But history may just have taken a turn with Assad’s agreement to join the Chemical Weapons Convention.

Tara Radakrishnan recently graduated from the University of Cambridge with an LLM in international law. She can be reached"

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