So, Obama’s aim is solely to affirm an international norm. To this end, he already has achieved something important. He has mobilized world attention, and there is now a chance, albeit small, that he might get a process in place that monitors and even destroys Syrian chemical weapons. Almost certainly he has ensured that such weapons won’t be used again by the Assad regime. That’s more than he could have achieved through airstrikes — which are unlikely to have destroyed such weapons. (Bombing chemical weapons facilities could easily release toxins into the atmosphere.) This is a significant success.

But to maintain that success, the administration will have to be clear that it does not seek any other goals, at least for now. Washington will have to live with Assad as a negotiating partner and guarantor of agreements. Should international inspections get underway, it would be difficult to threaten the use of force because inspectors would be in Syria — in harm’s way. Recall that U.N. inspectors had to be pulled out of Iraq before the 1998 bombing of Operation Desert Fox; the result was that the entire inspection system ended.