A Path to a Comprehensive Prohibition of the Use of Chemical Weapons under International Law: From The Hague to Damascus

The prohibition of the use of chemical weapons under international law has a long history dating back to the 19th century. Until the late 20th century, most of the endeavors by the international community had resulted in partial measures, not amounting to a comprehensive and absolute ban on their use, with limitations inherent in the relevant instruments, with the reservations put to the prohibitions or with different interpretations given to them. The recent use of chemical weapons in the Syrian civil war has revived the discussion on this issue. It is partly because although at that time Syria was a Contracting Party to the Geneva Protocol, which does not prohibit their use in civil war, and was not a State Party to the Chemical Weapons Convention, which may prohibit their use in internal armed conflict, the Security Council in Resolution 2118 (2013) declared that the use of chemical weapons in Syria is a violation of international law. This prompts us to examine whether the use of chemical weapons, including in internal armed conflict, is prohibited under customary international law. Moreover, a couple of years earlier, the Rome Statute of the International Criminal Court was amended to add to its list of crimes a use of chemical weapons in non-international armed conflict. With these facts in mind, this article examines the history of prohibiting the use of chemical weapons under international law, with particular reference to their use in internal armed conflict.