In recent days, I have participated in classified briefings about the use of chemical weapons in Syria. I also read the top-secret classified report made available to representatives and senators. The briefings and report contain the evidence supporting the administration's publicly stated conclusions; this evidence cannot be made public without compromising vital intelligence sources and methods.
Having reviewed the evidence, I have virtually no doubt that the administration's publicly stated conclusions are accurate: Bashar al-Assad's regime intentionally used chemical weapons on August 21 against opposition-controlled suburbs of Damascus. Alternative theories of culpability are not plausible at this time given the evidence I have reviewed. Assad's use of chemical weapons last month is consistent with his pattern of using such weapons to break a stalemate in areas that he has struggled to seize.