We don’t know key details about the reported chemical attack in Syria on April 4, 2017, but it raises two clear possibilities: Either Syria never fully complied with its 2013 promise to reveal all of its chemical weapons; or it did, but then converted otherwise non-lethal chemicals to military uses.
One way or another, subsequent events have proved Kerry wrong.
In fact, international investigators concluded last year that the Syrian government had gamed the system.
In October 2016, a joint effort by the United Nations and the Organization for the Prohibition of Chemical Weapons reported that Syrian Arab Armed Forces had dropped chemical-laden bombs four times between 2014 and 2015. (That conclusive evidence was not available at the time of the original fact-check. One of our principles is that we rate statements based on what is known at the time.)
The U.N. group also found that Islamic State units had fired shells filled with sulfur mustard (mustard gas) in an attack in 2015.
Syrian forces used chlorine gas in 2014 and 2015. Brian Finlay, president of the Stimson Center, a military and defense think tank in Washington, noted that Syria promised to rid itself of sarin, mustard and VX, a nerve agent. But chlorine-based chemicals present a different challenge.
"They can be used for perfectly legitimate and essential civilian purposes today, and repurposed tomorrow to perpetrate heinous crimes like those we witnessed in Syria this week," Finlay said.