Analysis: al-Qaeda in Syria unchecked by the US Reports of tensions between the two sides have been ongoing for more than a year now, ever since al-Qaeda-linked groups first joined the largely secular rebellion against President Bashar al-Assad. On the face of it, that alliance of convenience always seemed doomed to failure. After 40 years of secular Baathist rule under the Assad regime, ordinary Syrian Arabs had little obvious common cause with religious extremists, and plenty of very fresh memories of the horrors they inflicted next door in post-Saddam Iraq. But war also brings out the devout element in many people, and given the rebels' limited access to weapons, offers of help from well-equipped jihadis with skills honed against the mighty US army were unlikely to be turned down. The problem, though, is that whatever mutual purpose they may share on the battlefield, the two factions' visions in every other sense are very different. Even religiously conservative Syrians, of whom there are plenty, have little interest in the kind of Islamic mini-caliphate that al-Qaeda wants to set up, with its Sharia law backed by amputations and beheadings. Secular rebel groups also blame the jihadists for much of the sectarian violence against Syria's Shia minority, which al-Qaeda's extremist Sunni Muslim ideology views as an apostate creed. But having accepted the extremists into their ranks, it may not be that easy for the rebels to get rid of them. In the Sunni heartlands of post-Saddam Iraq, where al-Qaeda joined forces with local insurgents to fight the Americans, jihadists proved adept at subduing the communities they moved into, even in tough cities like Fallujah. It was only after four bloody years that their sheer brutality alienated their hosts, resulting in the so-called Sunni Awakening of 2007, where the insurgents accepted US help to turn on their al-Qaeda hosts. Could a similar anti-al-Qaeda rebellion take place in Syria now? Much as it might be a desirable outcome for both the rebels and the West, it seems far from guaranteed. For one, there is as yet no US willingness to lend the rebels a helping hand militarily. For another, the rebels are also still pre-occupied in fighting President Assad, who has been making ground in recent months with the help of Hizbollah. Moreover, in a chaotic, brutal civil war, one single beheading of one rebel commander may simply not be enough of a watershed moment. Sadly, al-Qaeda may have licence to commit many more atrocities before it outstays its welcome.