When the contracting parties to the Rome Statute establishing the International Criminal Court (1) met in Kampala in 2010 to discuss possible amendments to the statute, the main focus was, and has thereafter remained, on the crime of aggression. In addition to amending the statute to include the crime of aggression, (2) however, the contracting parties amended Article 8 of the statute to include a broader range of war crimes in noninternational armed conflicts over which the ICC can have jurisdiction (3)--inter alia, by including the use of chemical weapons. Although the latter amendment received much less attention from both the Kampala drafters and outside observers than the former, it is the use of chemical weapons that has come most quickly into play in world events. In particular, the use of chemical weapons by Syrian government forces in 2013 (and perhaps subsequently) has acutely raised questions concerning the extent of the ICC's treaty-based jurisdiction, both under the unamended text of the Rome Statute or in situations where the amendment to Article 8 applies. These events have also provoked consideration concerning the Security Council's legal powers to extend the ICC's jurisdiction to certain crimes involving chemical weapons that would otherwise be beyond its subject matter jurisdiction. These questions are considered in this Note.
We consider first, the basis of the now standard view that the use of chemical weapons constitutes a war crime under customary law in both international and noninternational armed conflicts; second, whether despite the intentional omission of references to chemical weapons in the original Rome Statute, the ICC's treaty-based jurisdiction extends in noninternational armed conflicts to the use of chemical weapons by states for which the Kampala amendment to Article 8 is not in force; and third, whether the Security Council may confer such ICC jurisdiction by way of a Security Council referral.
USE OF CHEMICAL WEAPONS IN INTERNATIONAL AND NONINTERNATIONAL ARMED CONFLICTS AS A WAR CRIME UNDER CUSTOMARY LAW
Chemical weapons were already used in ancient times, (4) and the partially related ban on the use of poison as a method of warfare ranks among the oldest prohibitions of warfare in international law. Article 70 of the 1863 Lieber Code had stated that the "use of poison in any manner, be it to poison wells, or food, or arms, is wholly excluded from modern warfare." (5) Declaration 2 Concerning Asphyxiating Gases adopted at the 1899 Hague Peace Conference prohibited "the use of projectiles the sole object of which is the diffusion of asphyxiating or deleterious gases." (6) Article 23(a) of the 1907 Regulations Concerning the Laws and Customs of War on Land prohibited the employment of "poison or poisoned weapons." (7) In reaction to the widespread use of chemical weapons during World War I, Article 171 of the Versailles Peace Treaty (8) declared that the "use of asphyxiating, poisonous or other gases and all analogous liquids, materials or devices [is] being prohibited." The Geneva Protocol for the Prohibition of the Use in War of Asphyxiating, Poisonous or Other Gases, and of Bacteriological Methods of Warfare, adopted in 1925 and now ratified or otherwise accepted by virtually all states, prohibits the use of "asphyxiating, poisonous or other gases, and of all analogous liquids, materials or devices." (9) What exactly was covered by this provision was immediately controversial, however--in particular, whether the use of nontoxic and anesthetic gases such as irritants or riot control agents was prohibited by the treaty or not. (10)
These treaties prohibiting poisonous weapons and asphyxiating gases were framed only in relation to international armed conflicts. (11) A much wider framing was articulated in the 1993 Convention on the Prohibition of the Development, Production, Stockpiling and Use of Chemical Weapons and on Their Destruction (Chemical Weapons Convention), under which the contracting states "undertake never under any circumstances" to use chemical weapons, a prohibition that applies to any armed conflict. (12) It was against this background that Colombia's Constitutional Court found in 1995 that the prohibition of the use of chemical weapons in noninternational armed conflicts forms part of customary international law. (13)
Shortly after the Colombian Constitutional Court judgment noted above, the Appeals Chamber of the International Criminal Tribunal for the Former Yugoslavia issued its landmark decision in Prosecutor v. Tadic. After an extensive survey of relevant state practice, the tribunal announced its view that the use of chemical weapons, even in noninternational armed conflicts, is contrary to international law. (14) The Appeals Chamber further implied that such use entails individual criminal responsibility, regardless of whether it takes place in internal or international armed conflicts (15)--a view later adopted in the International Committee of the Red Cross's study of customary international law. (16) This view is in some degree buttressed by the legislation of some states criminalizing the use of poison or poisoned weapons in both international and noninternational armed conflicts, (17) and it has, in effect, also been supported by the UN Security Council, notably in Resolution 2118 (2013). (18)
CHEMICAL WEAPONS AND THE DRAFTING OF THE 1998 ROME STATUTE
Scope of the Prohibition Ratione Materiae
During the drafting of what was to become Article 8 of the Rome Statute, the list of prohibited weapons proved to be among the most contentious questions. It was agreed to include express prohibitions of the use, in international armed conflicts, of "poison or poisoned weapons" and "asphyxiating, poisonous or other gases, and all analogous liquids, materials or devices." (19) Proposals were then also made to include a specific reference to the war crime of using "chemical weapons as defined in and prohibited by the 1993 Convention on the Prohibition of the Development, Production, Stockpiling and Use of Chemical Weapons and on Their Destruction"; (20) such proposals were still included, for example, in the so-called Zutphen draft statute of 1998. (21) During the Rome diplomatic conference (Rome Conference), the debate on the proposal to include a specific reference to the 1993 Chemical Weapons Convention in the list of war crimes became interwoven with the question of including a parallel specific reference to the use of nuclear weapons. Certain states, including Syria, claimed that listing chemical weapons, but not nuclear weapons, would be inherently "unfair," given that chemical weapons were, in effect, considered the "poor man's" weapon of mass destruction. (22) By contrast, nuclear weapons states, as well as those that were members of military alliances relying on nuclear weapons, rejected any inclusion of nuclear weapons in the list of prohibited weapons. In the final compromise neither nuclear nor chemical weapons were expressly listed as weapons whose use was prohibited under the Rome Statute.
Given this drafting history of Article 8 of the Rome Statute, it has been argued in relation to international armed conflicts that Article 8 might not cover all uses of chemical weapons as such. (23) This view is arguably buttressed by Article 22(2) of the statute, which provides both that the "definition of a crime shall be strictly construed" and that any such "definition shall be interpreted in favour of the person being investigated, prosecuted or convicted." (24)
In practice, many and perhaps all uses of lethal chemical weapons will fall within the Article 8 prohibitions of the use of "poison or poisoned weapons" and "asphyxiating, poisonous or other gases, and all analogous liquids, materials or devices." Although the dispute as to whether the 1925 Geneva protocol prohibits the use of nontoxic and anesthetic gases such as irritants or riot control agents is one that carries over into Article 8 of the Rome Statute, (25) other forms of chemical weapons--and certainly substances known to cause death or serious injury--are clearly covered by Article 8. The Elements of Crimes adopted by the states parties under Article 9 of the Rome Statute (26) confirm that the use of chemical weapons is covered by Article 8 as constituting a war crime in international armed conflicts: the relevant provisions of the Elements of Crimes require only the use of a "substance ... that ... causes death or serious damage to health in the ordinary course of events, through its toxic properties" (with regard to Article 8(2)(b)(xvii)) or the use of "gas or other analogous substance or device ... that ... causes death or serious damage to health in the ordinary course of events, through its asphyxiating or toxic properties" (with regard to Article 8(2)(b)(xviii)) in order for such use to constitute a war crime under the Rome Statute. (27)
These provisions of the Elements of Crimes also imply, however, that the use of riot control agents or of herbicides is not covered by the relevant provisions of Article 8. (28) This definition of prohibited chemical weapons is therefore narrower than Article 1(5) of the 1993 Chemical Weapons Convention, which explicitly also forbids the "use [of] riot control agents as a method of warfare." (29) Moreover, the formula used in the Elements of Crimes ("cause death or serious damage to health in the ordinary course of events, through its [asphyxiating or] toxic properties"), (30) while drawn in part from the definition of toxic chemicals in Article II(1)(a) of the Chemical Weapons Convention, does not adopt the Chemical Weapons Convention formula. The relevant phrase in the Chemical Weapons Convention is "can cause ... temporary incapacitation" (with no further qualification), (31) whereas the Elements of Crimes does not refer simply to temporary incapacitation or asphyxiation but requires that the "asphyxiating...