My approach would be to secretly arm all players (and tell McCain to keep his trap shut about it) and withdraw whatever forces we have in the area to inside Iraq...that includes stopping whatever coalition airstrikes we have lined up.
But more seriously, we have to take a wait and see approach. As the weeks drag by, Russia is going to have their hands full. Especially if the reports of Iran backed fighters flooding the area under Russian direction are to be believed. Plus, keep an eye on Turkey. Saudi Arabia is already planning on flooding the "militants" (pick any group you like) with high end weaponry... of course, this will mean the flood of migrants fleeing the area will increase into Europe, but at some point the EU will have to get serious and step to the plate about what to do.
The world has had the luxury of the United States carrying the load in the region for far to long, it is time for new leaders to emerge. Sadly, if the United States led by liberals continue the tepid inaction, we will have to live within the new dynamic.
By early 2014 these rebels were complaining that the pace was too slow and they needed anti-aircraft weapons. There was some talk(McCain) about giving them the anti-aircraft weapons but that ended when the airliner got shot in Ukraine.
So in Aug 2014, congress approved more money and expanded training to the military.
Because of this, the tide turned against Assad, so, Assad asked Putin for help. Of course Putin will deal with ISIS also, but, he needs to take care of these groups being supported by the US and the Gulf Sunni States who are the biggest threat to Assad.