For the West, there should be no turning back now. If the regime is left unpunished, Assad will become even more ruthless. The reverberations of Western inaction would be felt elsewhere too: America's enemies are surely paying attention. Obama may be extremely reluctant to act but even he should understand that it never had to come to this: had he been more decisive before, all this could have been avoided. But Obama, with his doctrine of realpolitik, was caught completely off guard by the Arab revolts that beautifully demonstrated the power of ideas, ideas that Obama's predecessor believed were not as alien to the ordinary Arab as was commonly and fashionably thought. America can now demonstrate that it stands behind those ideas by putting its money where its mouth is instead of being obsessed with maintaining the status quo, i.e., the one where ruthless dictators are kept in power for the sake of stability, breeding resentment toward America among the common folks.
To be sure, there are no easy solutions to the situation in Syria or the Greater Middle East in general. Arming moderate forces (probably easier said than done) within the opposition should alleviate the problem America faces with respect to Islamic rebels. Keeping boots off the ground seems like a no-brainer. As in Libya, air strikes and cruise missiles may be an effective and cheap solution (it should be noted that the West may wish for a regime change but doesn't seem eager to set that as an objective), contributing virtually nothing to America's long-term budget problems (which result from entitlement spending) while providing the kind of assets against the regime the rebels never could have dreamed of. In the long run, it can only be hoped that the ongoing revolutions mark the beginning of the end of autocracy in the Middle East, just as the 1848 revolutions did in Europe.