Much has been made of Obama referring to chemical weapon use in Syria as a ‘red line‘ that, if crossed, would invite intervention. Much has been more recently made of that intervention not materializing.
Ultimately, Obama has made a grave error here, which was rhetorically tying US policy to the use of chemical weapons in Syria. First of all, it continues acting as thought the category of ‘WMDs’ means anything, suggesting that chemical weapons are somehow comparable to nuclear ones. This is clearly false. Nuclear weapons have been used in one war, twice, in their entire history. Chemical weapons have been used hundreds if not thousands of times even since being putatively outlawed. From a geopolitical perspective, they are hardly decisive – from Flanders to Iran to Yemen, they have been used but without impacting the outcome of war. Morally, although they are horrific (Dulce et Decorum Est!), the last fifty years have been ample demonstration that high explosives and heavy weapons are at least as effective in killing civilians as chemical weapons.
However, Obama is correct in not, so far, reacting to news of chemical weapons used in Syria by preparing for any kind of intervention. First, there is no conclusive evidence that the Syrian government is mainly or exclusively responsible for using chemical weapons; even if there was conclusive evidence of widespread chemical attacks, there is a non-trivial chance they were used first by anti-government forces.
More importantly, however, Syrian chemical weapons do not have any effect on the overall situation. They are unlikely to substantially influence the course of the war or greatly increase the casualty toll. And their presence doesn’t do anything to consolidate the anti-government forces into something resembling an organization capable of governing Syria (or desirous of doing so in line with American ideals and interests), nor does it greatly increase the chance of the Syrian government collapsing quickly. Indeed, chemical weapons make a terrible Red Line because the major obstacles to a successful intervention in Syria are absolutely unaffected by their use. It’d be far more appropriate for US policy makers to be rhetorically honest – we will not intervene in Syria until the there is a real chance of the our intervention resulting in the removal of the Assad regime and the establishment of a government allied to the United States and respectful of human rights and democratic and human rights norms. Any other artificial line or trigger laid down will either be a another line crossed uneventfully, reducing US credibility, or (far worse) a source of greater pressure to intervene before doing so is advisable.