Correspondence

Abstract

pp. 301-20) find that non-state actors are more likely to use "crude" chemical weapons (CW), including toxic industrial chemicals such as chlorine or pesticides, rather than "traditional" chemical weapons, such as mustard or sarin gas. The authors conclude that successful efforts to counter non-state CW proliferation and use must differ substantially from those used against state programs, which are poorly equipped to mitigate the threat posed by nonstate crude chemical use. Their data supports these conclusions. However, their data extends only from 1970 to 2012, thereby excluding recent episodes of the use of militarized, traditional CW by the Islamic State (IS) organization. James Clapper, the director of national intelligence, stated on February 9, 2016, that IS used sulfur mustard in an attack in Syria in August 2015. 1 Mr. Clapper explained that IS made and deployed the CW, and has the potential to continue to do so; a subsequently reported attack on the Syrian airbase in Deir Ezzor with mustard gas delivered by rockets appears consistent with this warning. 2 It is evident that IS favors the use of militarized traditional CW, apparently drawing on weapons or precursors acquired from captured state stockpiles.Alley and Jones's concern over the effectiveness of CW nonproliferation and counterterrorism efforts is valid. More should be done to counter crude CW proliferation among non-state actors. But whatever form these efforts should take, they should not come at the expense of addressing states' CW programs. If IS offers any indication, non-state actors with an interest in battlefield applications of CW will seek to progress to more sophisticated threats over time, and will take advantage of existing state programs to do so. This problem can be mitigated using existing mechanisms, such as those provided by the Organisation for the Prohibition of Chemical Weapons. Nothing is likely to be more effective against this high-end non-state threat than redoubling efforts to bring remaining states into the Chemical Weapons Convention, verifying their declarations, and completing the timely destruction of CW stockpiles.