The Syrian government sets its conditions for agreeing to give up its chemical weapons:

Syrian President Bashar al-Assad added to the tension by saying that he is willing to place his chemical arsenal under international control — but only if the United States stops threatening military action and arming rebel forces trying to unseat him.

It seems unlikely that the administration would be willing to take this kind of deal. In their attempt to win over hawks in Congress, the administration already committed to increasing military assistance to the opposition, and ruling out military action will be treated as “giving in” to Syria. There is a strong aversion in the U.S. to be seen as “rewarding” authoritarian regimes, which is why negotiating with these regimes is politically much harder than it should be. It costs the U.S. nothing to agree to these terms, but these terms will likely be viewed as unacceptable in Washington. The administration will want to treat its support for the opposition as separate, and it will always want to reserve the option to attack. That isn’t because either position makes any sense for the U.S., but because the administration has trapped itself into commitments that it won’t easily repudiate. The Syrian government may not truly be willing to give up its chemical weapons, but it is doubtful that the U.S. would be willing to accept the exchange that might be required to make the deal work.