U.S. President Barack Obama called it “a potentially huge victory,” while some of his critics saw it as a toothless concession to Russia – the resolution does not set an automatic trigger to punish the Assad regime, if it falters in its obligations. The Economist laid out a thorough analysis of what’s in the resolution, and what’s missing from it: notably, any blame for the August 21 chemical weapons attack on eastern Ghouta, which raised the prospect of a U.S. military strike.

The U.N. move did endorse a political transition in Syria, first proposed at the Geneva Peace Talks in June 2012 (see the U.N. communique here). U.N. Secretary-General Ban Ki-moon said that major powers hoped to hold a follow-up peace conference known as Geneva II in mid-November, according to Reuters. Both the Assad regime and the opposition have suggested they would go.

One snag, among others, is the breakdown of any rebel cohesion on the ground. Syria’s armed opposition, the decentralized forces that are fighting Assad’s army, have never formed a unified front. But in the past few weeks they’ve become even more dangerously splintered. We’ve seen moderate brigades joining Jabhat al-Nusra, out of a perceived need for protection from other al-Qaida-linked groups, an escalating fight between Islamists and Kurds, and a wholesale rejection of the opposition’s political leadership abroad. Eleven Islamist rebel groups came together to denounce the Syrian National Coalition, the U.S.-backed body that represented the anti-Assad camp.

“The National Coalition and its transitional government led by Ahmed Tomeh do not represent it and will not be recognized,” they said in a joint statement quoted by the BBC. Instead they insisted that the opposition should unite under an “Islamic framework.”

That makes it harder to negotiate a lasting peace or any kind of effective cease-fire in Syria, without including the rebel groups that the U.S. and its allies find least palatable.