Syria: international law and the use of chemical weapons

The ongoing unrest in Syria has continued to dominate the headlines as concerns have mounted about the country’s chemical weapons stockpiles. At the same time, these stockpiles raise interesting questions of international law.

The isolated state has long been understood to have a well-developed chemical weapons programme and large stockpiles of usable agents and warheads. Concerns about suspected chemical weapons, however, recently reached a fever pitch when a Foreign Ministry spokesman, Jihad Makdissi – in a move from Syria’s historical position of neither confirming nor denying a chemical, or biological, weapons programme – officially acknowledged their existence by announcing to the international community, on 23 July, that these weapons would not be used against civilians, but would be used in the event of ‘external aggression’. The regime subsequently qualified its statement, in an attempt to retain a perception of ambiguity over their actual existence. While there is uncertainty about whether Makdissi’s statement was meant as reassurance that the Assad government will maintain some restraint against its own civilians, or as a threat against the international community, Syria’s acknowledgment of its chemical weapons brings renewed focus to the status of chemical weapons use under international law.

The use of chemical weapons is very clearly prohibited in international law under a number of different legal instruments. Syria is not a party to the 1993 Chemical Weapons Convention (CWC), which unequivocally prohibits chemical weapons use (and other activities) under any circumstances. However, in 1968, Syria acceded to the 1925 Geneva Protocol, which prohibits the use in war of asphyxiating, poisonous or other gases, and of bacteriological methods of warfare. Russian President Vladimir Putin, who has continued to support the Assad regime, publicly reminded Syria of its obligations under the Geneva Protocol after their acknowledgement of chemical weapons stockpiles.

Syria’s adherence to the Geneva Protocol may have led the Assad regime to think twice about using chemical weapons against Syrian civilians – in what has now been declared a ‘non-international armed conflict’ by the International Committee of the Red Cross (ICRC) – even if the treaty was originally intended to cover international conflicts. The ICRC concluded in 2005 that customary international humanitarian law includes a ban on the use of chemical weapons in internal as well as international conflicts, and an appellate chamber in the International Criminal Tribunal for the former Yugoslavia (ICTY) noted in 1995, in Prosecutor v. Tadic, that ‘there had 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’.

Yet what are we to make of Syria’s threat to use chemical weapons in the event of ‘external aggression’? Again, as a state party to the Geneva Protocol, Syria is bound to refrain from any use of chemical weapons in international armed conflict. Their use in the event of ‘external aggression’ would therefore be a treaty violation and a violation of customary international humanitarian law. Such use could also trigger co-operation between the UN and the Organisation for the Prohibition of Chemical Weapons under the UN Secretary-General’s Mechanism for Investigation of Alleged Use of Chemical and Biological Weapons and Part XI, Paragraph 27 of the Verification Annex to the Chemical Weapons Convention. More