Turkey will do it. We won't be sending anyone in. Syria's already attacked inside Turkey, and made them very pissed. This was a big mistake. Turkey has a large and extremely professional army, and they will take Syria's apart in no time. Remember, Turkey is a part of NATO. The Arabs, all of them, want no part of a conflict with Turkey. Assad's not gassing anyone. He may be brutal, but he ain't stupid.
The sarin gas is locked and loaded. Like most middle eastern nuts, Assad will most likely attempt to start a regional conflict and not just kill his own people but launch against Isreal, Turkey etc If he is willing to do that, I'm sure he is more than willing to let a few cannisters slip into the hands of terrorists as well. Unfortunatley it's not as simple as him killing his own people, he's going to try and drag everyone down with him. obama will be on vacation no doubt.