I am myself personally unsure of the best course of action for the US in Syria; I am appalled by the horrendous war crimes of the Asad regime and its unrestrained war on its own people; I certainly support US humanitarian aid and even arms supplies to the rebels, but I have doubts about more overt assistance. If Turkey or NATO could provide a no-fly zone it would probably make a difference, but that seems unlikely unless the US takes the lead. Syria is not Libya (assuming you consider the Libyan intervention a success), and the war will last longer and be far more likely to spread than was the case in Libya. But the debate may soon be overtaken by events.
First there were the reports of chemical weapons use, and the debate about the so-called US "red line." Then, last week, Hizbullah acknowledged that it has had fighters engaged inside Syria. Then, this weekend,. Israel struck twice inside Syria, allegedly at missiles en route to Hizbullah, but possibly also aimed at degrading Syria's own missile stocks, which would be a major delivery system for chemical weapons. We may not know all the details for some time. But Hizbullah and Israel have both ante'd up in this game of bloody regional poker.
Iran on one side (with Iraq sympathetic) and Turkey, Saudi Arabia, Qatar and Jordan on the other have been in the game all along. Lebanon, as always, doesn't really have a hand to play but is nonetheless part of the stakes.
At first the Syrian civil war seemed to be an outgrowth of Arab Spring; then a Sunni-Shi‘ite sectarian conflict, then a geopolitical fight between Iran/Syria and the conservative Sunni states. But as the up-escalator accelerates it's moving into an area where all the parties may be losing sight of what the fight was originally about. There's a story that after World War I the deposed Kaiser Wilhelm II was asked what the thought the Great War had really been "about," and he replied, "I'll be damned if I ever knew." By the time you get to the Somme or Gallipoli, it's not about an Austrian Archduke any more (if it ever was).
I am still uncertain what the best way may be to end the Syrian atrocities, but the stakes were raised this weekend. Both the dangers of widespread war and unforeseen consequences have risen. I don't recommend dithering unduly, but one also needs to think carefully before taking precipitate action. Caution, yes, but it may also be time to find ways to short circuit this escalator before the war metastasizes. The addition in less than a week of both Hizbullah and Israel adds to both the need for caution and the need for action to defuse this or decide it before the escalator goes through the roof.