Guest Post: The Use of Chemical Weapons is not a Crime against Humanity

By Catherine Harwood, Grotius Centre for International Legal Studies

The use of chemical weapons in Syria in August 2013 has generated widespread international outrage. International actors have condemned the use of chemical weapons and have employed the language of international criminal law to convey the severity of the violation. The UN Secretary-General stated that “[a]ny use of chemical weapons anywhere, by anybody, under any circumstances, would violate international law. Such a crime against humanity should result in serious consequences for the perpetrator.” Similar sentiments were expressed by the Bureau of the Parliamentary Assembly of the Council of Europe. US President Obama also labelled chemical weapons “a crime against humanity, and a violation of the laws of war”.  The use of chemical weapons is prohibited under both conventional and customary international law and may be prosecuted as a war crime. But does the prohibition extend to liability under international criminal law as a crime against humanity?

Many voices have called on the Security Council to refer Syria to the ICC.  Although practical prospects of referral remain doubtful, the ICC is in principle an appropriate institution to conduct international prosecutions regarding the situation in Syria. If a prosecution is initiated, many may expect to see the use of chemical weapons reflected in the charge sheet.  In light of this, the question whether the use of chemical weapons could amount to a crime against humanity is explored by reference to the Rome Statute. This inquiry explores the statements by the UN Secretary-General and others that any and all uses of chemical weapons amount to crimes against humanity.

• The use of chemical weapons as a war crime

Despite the wide prohibition of the use of chemical weapons in international law, the Rome Statute does not expressly prohibit ‘chemical’ weapons.  However, several provisions indirectly prohibit their use in international and non-international armed conflicts. At first glance, article 8(2)(c)(xx), which prohibits the use of weapons “of a nature to cause superfluous injury or unnecessary suffering or which are inherently indiscriminate”, appears most applicable. However, this provision only prohibits weapons listed in an annex to the Statute, which has never been created.  In addition, it only applies to international armed conflicts, which would exclude the conflict in Syria. 

The Rome Statute also prohibits the use of employing “poison or poisoned weapons” under articles 8(2)(b)(xvii) and 8(2)(e)(xiii); and “asphyxiating, poisonous or other gases, and all analogous liquids, materials or devices” in articles 8(2)(b)(xviii) and 8(2)(e)(xiv). These broad provisions arguably include chemical weapons, but they have not yet been applied in practice. Some controversy surrounds the interpretation of these provisions, as noted by Dapo Akande and Bill Schabas, who both consider that the Statute can and should be read as prohibiting chemical weapons.

The use of chemical weapons could also be prosecuted when used in prohibited circumstances or when their use leads to prohibited results. The use of chemical weapons could be prosecuted where it amounts to an attack that is directed against civilians under arts. 8(2)(b)(i) and 8(2)(e)(i); or is an intentionally disproportionate attack under art. 8(2)(b)(iv).  Curiously, the  latter prohibition does not apply to non-international armed conflicts. Prosecutions could also result when the use of chemical weapons results in death or great suffering or injury to protected persons under the Geneva Conventions under arts. 8(2)(a)(i) and (iii) and 8(2)(c)(i). In short, both the use and consequences of chemical weapons may be prosecuted as war crimes. More extensive prohibition against their use would be possible if chemical agents were listed in the annex referred to in article (2)(c)(xx), and if this provision also applied to non-international armed conflicts.

• The use of chemical weapons as a crime against humanity

Under articles 7(1) and 7(2)(a) of the Rome Statute, crimes against humanity are prohibited acts listed in article 7(1) when committed in the context of a “widespread or systematic attack directed against any civilian population, with knowledge of the attack”,  “pursuant to or in furtherance of a State or organizational policy to commit such attack.” The Elements of Crimes provide that a relevant attack is a “course of conduct involving the multiple commission of acts referred to in [article 7(1)] against any civilian population […] The acts need not constitute a military attack. It is understood that ‘policy to commit such attack’ requires that the State or organization actively promote or encourage such an attack against a civilian population”.  ICC Pre-Trial Chamber II interpreted the contextual elements of crimes against humanity in the Bemba confirmation of charges decision. The PTC held that “[t]he commission of the acts referred to in article 7(1) of the Statute constitute the ‘attack’ itself” (para. 75). The attack must be either widespread or systematic. A widespread attack is “large-scale”; “over a large geographical area or an attack in a small geographical area directed against a large number of civilians” (para. 83). The civilian population “must be the primary object of the attack and not just an incidental victim of the attack” (para. 76). The state or organisational policy may be “made by groups of persons who govern a specific territory or by any organization with the capability to commit a widespread or systematic attack against a civilian population”. An attack that is “planned, directed or organized - as opposed to spontaneous or isolated acts of violence” (para. 81) is sufficient to satisfy this requirement.

The list of prohibited acts in article 7(1) strikes twice against the statement ‘the use of chemical weapons is a crime against humanity’: first, at the level of contextual elements; and secondly, in respect of the prohibited acts. An ‘attack’ is comprised of prohibited acts referred to in article 7(1); and only those acts listed in article 7(1) may amount to crimes against humanity. The use of chemical weapons is not listed in article 7(1). Rather,  potential consequences of the use of chemical weapons are relevant, such as murder (article 7(1)(a)) and “other inhumane acts of a similar character intentionally causing great suffering, or serious injury” (article 7(1)(k)).  Thus, the consequences of chemical weapons, not their use per se, could amount to an attack as well as the prohibited acts. Although the use of chemical weapons and their terrible consequences often go together, they are distinguishable.

Assuming that the use of chemical weapons results in prohibited acts listed in article 7(1), several other criteria must be met before these consequences may amount to crimes against humanity. The attack must be widespread or systematic. The civilian population must also be the primary object of the attack. This element may be difficult to prove in an armed conflict, as it might be argued that chemical weapons were intended to be used against combatants and that the civilian population was an incidental victim.  However, it could be contended that the indiscriminate nature of these weapons means that any use must be regarded as making the civilian population the primary object of attack, despite any military motive. The attack must also be pursuant to a state or organisational policy. There are many possible scenarios in which this criterion would not be met. Chemical weapons might be deployed in violation of military orders; used in an unplanned or unorganised way; or used without the organisation’s active encouragement. Thus, even if the ‘use of chemical weapons’ is interpreted widely to include the consequences of use, only those consequences that are planned and sufficiently serious may amount to crimes against humanity.

• Concluding thoughts

The prohibition on the use of chemical weapons has more recognition as a war crime, rather than as a crime against humanity.  While the ‘mere’ use of chemical weapons can amount to a war crime, only the consequences of chemical weapons, not their use per se, may be crimes against humanity.  Why then is there such an emphasis in political rhetoric that any and all use of chemical weapons is a crime against humanity?  A cynic may suggest that the label ‘crime against humanity’ has more political currency than ‘war crime’, so that its use could encourage compliance and enforcement action. Whether or not the emphasis is strategic, what is clear is that international political actors, the media and the public are engaging with concepts of international criminal law in connection with the conflict in Syria. While there is arguably greater public awareness  of international criminal law as a result of this discourse, it would be ultimately detrimental if key legal concepts are confused.  While situations of mass atrocity may amount to crimes against humanity,  ‘crimes against humanity’ is not a byword for atrocity. In the interests of clarity, public education and with an eye to expectations of victims in any eventual prosecutions, concepts of international criminal law deserve more careful  treatment.