Military intervention in Syria?

Both Foreign Policy's Marc Lynch and an editorial in The Economist argue that the time isn't right for the world to intervene; Anne-Marie Slaughter takes the contrary view:

It is a game of perceptions and assumptions, whereby the international community has tried to make Assad's fall seem inevitable and Assad himself has made clear that he will not be cowed into leaving or making real concessions. Injecting the possibility of armed intervention to protect opposition protesters into this mix, with the accompanying prospect of a much longer and much more destructive conflict in which more members of the military could defect to the Free Syrian Army, could tip this domestic political balance in favor of a negotiated deal and put real internal pressure on Assad. It is still true, however, that the credible threat of force requires an actual willingness to make good on that threat.

(Video: "After online calls for a "day of dignity", protesters demanding an end to alleged government corruption took to the streets of cities across Syria on Friday. But they were met with a violent crackdown orchestrated by state security forces. In one video subsequently posted online, water cannon are used on crowds of protesters. Al Jazeera's Bernard Smith reports on the "Facebook youth" who appear to be keeping one step ahead of the authorities.")