One, Assad has continued to kill. Assad is the problem rather than any particular weapon used to kill.
Two, Assad can just use chemical weapons that weren't part of his declared arsenal:
Syria has vowed to hand over or destroy its entire arsenal by the end of this week, but still has roughly 14 percent of the chemicals it declared to the Organisation for the Prohibition of Chemical Weapons (OPCW).
In addition, chlorine gas that was never included on the list submitted to the OPCW is now allegedly being used on the battlefield, leading some countries to consider requesting an investigation, possibly through the United Nations.
Attacks this month in several areas of the country share characteristics that have led analysts to believe that there is a coordinated chlorine campaign, with growing evidence that it is the government side dropping the bombs.
Assad's arsenal was declared, secured, and is in the process of being shipped out. But still Assad manages a chemical weapons attack.
Remember that Saddam had far more deadly raw materials on hand when we overthrew his regime, yet anti-war activists still judge that we invaded Iraq over a mistake (or even more bizarrely, a "lie" that even Democrats familiar with Clinton-era intelligence believed true).
Assad is the weapon of mass destruction. Deals designed to limit what weapons he can use to kill just tests his ingenuity without slowing down the rate of killing.
This is "smart" diplomacy, of course.
