Recent events in the Syrian civil war have proved an unparalleled test of the norm against the use of chemical weapons. At its core this was a test of the willingness of countries to uphold the norm, in this case in the face of a flagrant violation, and a response that in the end stumbled upon a satisfactory conclusion—reaffirming the special category of chemical arms—but which in the process said a great deal about current attitudes to the use of military force as a means of humanitarian intervention.