The Precedent Set by the US Reprisal Against the Use of Chemical Weapons in Syria

In his recent post on the United States’ missile strike against a Syrian airbase, on 6 April 2017, Marko Milanovic focused primarily on the unlawfulness of that action (here). While I agree with that view, in this post, I wish to focus on the nature of the precedent which the US reprisal has set. Moreover, I argue that this instance of use of a forcible countermeasure by a permanent member of the UN Security Council (UNSC) should serve to refocus attention on a dysfunctional UNSC.

Three remarks at the outset: (a) This post concerns only “forcible countermeasures” or “reprisals”; (b) I characterise the US missile strikes as a reprisal against Syria’s use of chemical weapons. Although other characterisations have been proffered (for instance, humanitarian intervention or providing assistance in a counter-insurgency), the US administration has framed its actions primarily in terms of a forcible response to the use of chemical weapons (see below); and (c) I rely on the assumption, tendered by the US but disputed by Russia, that Syria was responsible for the chemical attack.

The Legal Framework

A useful starting point for this discussion are the Draft Articles on Responsibility of States for Internationally Wrongful Acts, adopted by the International Law Commission (ILC) in 2001, which have been said to present “a combination of codification and progressive development” (Harris, Cases and Materials on International Law, p. 422). Article 49(1) of the Draft Articles states that “An injured State may only take countermeasures against a State which is responsible for an internationally wrongful act in order to induce that State to comply with its obligations…” Thus, while the Draft Articles envisage the lawfulness of countermeasures in certain circumstances, it is important to clarify briefly: (1) which countermeasures are envisaged; and (2) which party may undertake them.

As regards which countermeasures are envisaged, Article 50 (1)(a) of the Draft Articles states that “(1) Countermeasures shall not affect…(a) the obligation to refrain from the threat or use of force as embodied in the Charter of the United Nations.” Thus, Article 50 prohibits forcible countermeasures or reprisals, and this prohibition is consistent “with prevailing doctrine as well as a number of authoritative pronouncements of international judicial and other bodies” (Harris, Cases and Materials on International Law, p. 457).

As regards which party may undertake the countermeasures envisaged by the Draft Articles, only a state injured by the violation may resort to counter measures against the wrongdoer (Crawford, Brownlie’s Principles of Public International Law, p. 588). Crawford notes that, during the ILC discussions, the question of whether serious breaches of peremptory norms “do not entail a right to take countermeasures in the collective interest” did arise. However, as a result of “strong reactions from many states, concerned in particular with the potential for arbitrariness in imposition of third-party countermeasures”, the possibility for such action was dropped. The result is that there is “no clearly recognized entitlement of [non-injured states] to take countermeasures in the collective interest” (Crawford, p. 588). In any event, however, such an entitlement would only have related to non-forcible countermeasures, and not the type of forcible countermeasures with which this post is concerned.

Therefore, the prevailing view is that there is a general prohibition of forcible countermeasures or reprisals in the lex lata. As Milanovic noted, “[i]nternational law does not permit forcible reprisals that would breach Article 2(4).” This position is shared by most international lawyers (see Gardam, Necessity, Proportionality and the Use of Force by States, p. 140). One reason for this is that “…many reprisals may lead to a chain of violent conduct and counter-reprisals. This dangerous potential becomes evident when reprisals are used as a form of revenge” (see Mitchell, “Does one illegality merit another? The law of belligerent reprisals in international law” 155 Military Law Review (2001) p. 172).

Admittedly, in Nicaragua, the Court appeared to have left the door open for some lower-level, smaller-scale forcible countermeasures on the part of the injured State (Nicaragua, ICJ Reports 1986, p. 127, para. 249). In his separate opinion in Oil Platforms, Judge Simma observed that, in Nicaragua:

“the Court drew a distinction between measures taken in legitimate self-defence on the basis of Article 51 of the Charter and lower-level, smaller-scale proportionate counter-measures which do not need to be based on that provision…” (Oil Platforms, ICJ Reports 2003 – Separate Opinion of Judge Simma, p. 332).

However, this possibility is not considered further in this post, because I do not consider that the US reprisal of 6 April 2017 (discussed below) could be characterised as lower-level and smaller-scale, in accordance with the understanding of that case.

The US reprisal

The US strikes against Syria were undertaken in reprisal for the “worst chemical attack in years in Syria”, on 4 April 2017, as a result of which “[d]ozens of people, including children, died – some writhing, choking, gasping or foaming at the mouth” (see here). In a statement of 6 April 2017, President Trump stated:

My fellow Americans: On Tuesday, Syrian dictator Bashar al-Assad launched a horrible chemical weapons attack on innocent civilians. Using a deadly nerve agent, Assad choked out the lives of helpless men, women, and children. It was a slow and brutal death for so many. Even beautiful babies were cruelly murdered in this very barbaric attack. No child of God should ever suffer such horror.

Tonight, I ordered a targeted military strike on the airfield in Syria from where the chemical attack was launched. It is in this vital national security interest of the United States to prevent and deter the spread and use of deadly chemical weapons. There can be no dispute that Syria used banned chemical weapons, violated its obligations under the Chemical Weapons Convention, and ignored the urging of the U.N. Security Council.

The following day, the US Secretary of State, Tillerson further explained that:

“this particular strike that was carried out on the airbase from which the chemical weapons attack was launched was very deliberately considered by the President. It is a response that we believe is both proportional and appropriate” (see here).

From an evaluation of the available facts, on 6 April 2017, the US used force against Syria in reprisal for Syria’s use of chemical weapons, contrary to Article 1 of the Chemical Weapons Convention, 1993 (“CWC”). Article 1 of the CWC requires States Parties “never under any circumstances: (a) To develop, produce, otherwise acquire, stockpile or retain chemical weapons, or transfer, directly or indirectly, chemical weapons to anyone; (b) To use chemical weapons…” The CWC entered into force in Syria on 14 October 2013 (see here). Moreover, in view of its almost universal acceptance, this prohibition is considered to reflect customary international law.

It is submitted that the US reprisal of 6 April 2017 was in contravention of the general prohibition of forcible countermeasures or reprisals discussed above. Even though it was undertaken in response to another internationally wrongful act (Syria’s breach of the prohibition of the use of chemical weapons), both of these actions were unlawful in the lex lata. In this respect, even though there has been discussion of whether the law on the use of force should be changed (see here and here), that is a separate issue.

However, it is not sufficient to state that the US reprisal was unlawful and stop there. I think, particularly with an eye to precedent, it is necessary to carefully consider the discrete nature of the precedent set by the US reprisal, particularly, in view of its potential longer term impact on Article 2(4) of the UN Charter.

Firstly, the reprisal was undertaken in a context where the UNSC (and the possibility for collective action) was stultified by veto. That the permanent members of the UNSC could not find common ground and take collective action in the face of something as egregious as the use of chemical weapons is troubling, and an issue I will return to in the conclusion. Secondly, the reprisal was undertaken in response to the use of chemical weapons, in flagrant breach of the international prohibition on the use of such weapons. Thirdly, the reprisal was proportionate and characterised by restraint, both in terms of its official description and the facts on the ground. President Trump spoke of “a targeted military strike” and Secretary Tillerson referred to a “proportional and appropriate” response. Although it is difficult to measure proportionality in such cases (see Gardam, p. 155), the military strikes where limited with respect to geography and destructive scope, limited with respect to temporal scope, and specifically targeted the infrastructure (airfield) from where the chemical attack was allegedly launched. Fourthly, the effects of the US reprisal was, in the terms of Gabčíkovo-Nagymaros Project, reversible (Gabčíkovo-Nagymaros Project, ICJ Reports 1997, p. 7 at pp.56-57). It was undertaken in the dead of night and, from the available information, did not involve loss of life – but destruction of infrastructure.

Finally, this reprisal had to be seen in a context where there existed the very real risk that Syria would use chemical weapons against its own population again with impunity, as it had already done in the past. The US considered itself directly “injured” by such action in view, in the words of President Trump, of the “vital national security interest of the United States to prevent and deter the spread and use of deadly chemical weapons.” In this connection, it is notable that, during the Second World War, President Roosevelt threatened reprisals against the Axis Powers if they used poison gas, and some have argued that this threat compelled the Axis Powers to refrain from using poison gas in the battlefield although, as is well known, the tragic history of use of Zyklon B in the gas chambers is well-documented (see Mitchell, p.171). If (and only time will tell) the US reprisal has the effect of forestalling repeated use of chemical weapons in Syria then, on balance, it is not a bad result for international law.

This does not in any way detract from the international wrongfulness of US action. It is also true that this action may have served to undermine the prohibition on the use of force in Article 2(4) of the UN Charter. It is arguable, however, that the alternative of watching idly in the face of repeated uses of chemical weapons would also have eaten away at the core of international law. The choice lied somewhere on the spectrum between Captain Vere’s strict adherence to the law “however pitilessly that law may operate” (Melville, Billy Budd) and Thoreau’s invocation that “we should be men first, and subjects afterward. It is not desirable to cultivate a respect for the law, so much as for the right” (Thoreau, Civil Disobedience).

In this respect, I agree with Franck that “[l]aw is strengthened when it avoids absurdly rigid absolutes” (Franck, Recourse to Force: State Action Against Threats and Armed Attacks, p. 172). In the domestic sphere, Franck referred to the cases of Regina v. Dudley and Stephens (14 QBD 273 (1884)) and United States v. Holmes (26 Fed. Cas. 360, 1 Wall Jr. 1 (1842)) as instances where “law in some limited circumstances may condone or excuse with what is required by law in every circumstances” (Franck, p.173). I agree with his general argument that, in some limited circumstances, unlawful behaviour may be mitigated in view of certain extenuating or mitigating factors. This is different from suggesting, as has sometimes been the case with respect to humanitarian intervention, that certain behaviour should be considered legal because it is legitimate or, indeed, conflating the two concepts (see here).

My view is that, in the lex lata, the US reprisal of 6 April 2017 was unlawful. However, in view of the extenuating circumstances discussed above and, in particular, Syria’s egregious use of chemical weapons, there could be grounds for mitigation. After all, as Franck noted:

“[w]hen law permits or even requires behaviour that is widely held to be unfair, immoral or unjust, it is not only persons but also the law that suffers. So, too, if the law prohibits that which is widely believed to be just and moral” (see Franck, p. 178).

In conclusion, this case should serve to refocus attention on the (dys)functioning of the UNSC and its inability to act in face of egregious threats to international peace and security when the interests of one of the permanent members (or its allies) are invested. This has perpetuated a structural deficiency in the international legal framework which has a direct impact on other elements of the UN Charter, including Article 2(4). There is no easy solution. While comprehensive reform of the UNSC may be out of reach for the present, international lawyers should continue to make sure the matter remains on the international agenda and to lobby for “pragmatic modifications in the Security Council’s working methods” (Weiss, “The Illusion of UN Security Council Reform” 26 The Washington Quarterly, (2003), p.154).