The Real Issue in Syria
Obama drew a blurred line in the sand for Assad over chemical weapons. Assad tiptoed up to the line and danced over it, and Obama did nothing. Assad drove over the line in his pickup and set up his tent. Now Obama is trapped. The last thing he wanted was another war in Asia. He already let the military persuade him that an unwinnable war in Afghanistan could be won, and he got burned. Between his vague threat and dilatory behavior he really is stuck.
Yglesias and others have pointed out that any intervention in Syria is an extremely cost ineffective way to save lives - it's more likely to kill more people than it saves in any case. In my opinion, though, that's not the point. The real point is our other vague threat in the Middle East - the one where we (he) said that we wouldn't permit Iran to get nukes.
If Obama folds on Syria, or, more likely, settles for purely symbolic mini-strikes, Assad will see a giant green light, and so will Iran.
Of course the worst thing now is that there are no good options. If Assad loses, Syria likely becomes a failed state dominated by jihadis. If he win, Hezbullah and Iran win.
I think maybe Obama should have been more specific in his initial threat, like, "If you use Chemical Weapons we will kill your Air Force." He should probably do that now anyway.