Michael Totten has a good overview of the options with Syria, and Israel's recent threat of regime change:

There are good reasons to feel squeamish about the aftermath of regime change, whether it comes at the hands of Israelis or not. The same sectarian monster that stalks Lebanon and Iraq lives just under the floorboards in Syria. The majority of Syria’s people are Sunni Arabs, but 30 percent or so are Christians, Druze, Alawites, or Kurds. Assad himself is an Alawite, as are most of the elite in the ruling Baath Party, the secret police, and the military. Their very survival depends on keeping Syria’s sectarianism suppressed. The country could easily come apart without Assad’s government enforcing domestic peace at the point of a gun. This is a serious problem...

I’d love to see Assad get his just desserts after what he’s done to his neighbors and his countrymen. It will be terrific if his Arab Socialist Baath Party regime is replaced with something more moderate and civilized. The odds of a smooth transition and a happy ending, though, are not great. Syria has no grassroots movement demanding democratic change right now as Iran does. The Israelis are right to be cautious.

But they’re also right to threaten to pull Assad’s plug if he doesn’t back off. He’s a lot less likely even to start the next war if he knows he’ll be held accountable. The fact that he can suppress sectarian violence at home isn’t worth much if he won’t stop exporting it everywhere else.