Russia and China would be much harder pressed to oppose an initiative from these emerging powers than from the usual clutch of Western states in the Security Council. The Gulf can put some pressure on China here -- Beijing is distracted by its own problems right now, and how much longer it will provide cover to Moscow's errant allies in Syria remains to be seen.
And if the Security Council won't authorize an international force, NATO or the Arab League could. NATO has been desperate to avoid getting dragged into Syria, but providing diplomatic cover for a multinational force is a different story.
Of course, some of U.S. President Barack Obama's critics would no doubt charge that letting Turkey and others drive a proposal forward amounts to another example of "leading from behind" -- but that criticism would be infantile, and the Obama administration has earned more than enough foreign-policy credibility to turn the other cheek. Once authorized, a force would certainly need U.S. intelligence and tactical support, but not American boots on the ground.
All of this, it bears repeating, is unlikely. There's no overnight deus ex machina here. First, several more days will pass in diplomatic overtime trying to rescue Annan's plan -- infuriatingly so for Syrian civilians, but realistically the right call. Those frustrated by the slow pace of diplomacy must remember that military options will take weeks, if not months, to organize.
Still, faced with a range of other dreadful choices, this one might balance the pros and cons less badly than some. Right now, the so-called international community faces all bad choices, and Assad has the choice of continued slaughter -- in slow motion or high gear. If and when diplomacy does finally fail, the decision to form a multinational force to protect civilians could turn the tables and confront Assad's supporters with bad choices of their own.