One of the main reasons that an intervention in Syria has not begun is that politicians, diplomats, and intelligence officials are rightly concerned about the influence of jihadist fighters within Assad's opposition. One group in particular, Jabhat Al Nusra, has received quite a bit of attention not only because of the jihadist beliefs that motivate its members but also because it has been playing a significant role in the conflict. Jabhat Al Nusra was labeled as a terrorist organization by the American government six months ago.
As worrying as Jabhat Al Nusra is it has recently been reported that Al Qaeda in Iraq is becoming increasingly involved in the Syrian civil war, and is beginning to overshadowing Jabhat Al Nusra.
It might initially seem that another jihadist group getting more involved in the fight against Assad does not change much. However, it appears that Al Qaeda in Iraq have goals that would have a significant impact on the region if the rebels succeed in overthrowing Assad.
Al Qaeda's Iraq-based wing, which nurtured Nusra in the early stages of the rebellion against Assad, has moved in and sidelined the organization, Nusra sources and other rebels say.
Al Qaeda in Iraq includes thousands of foreign fighters whose ultimate goal is not toppling Assad but the anti-Western jihad of al Qaeda leader Ayman al-Zawahri—a shift which could extend Syria's conflict well beyond any political accord between Assad and his foes. The fighting has already cost 90,000 lives.
With Assad gone it will be easier for Al Qaeda in Iraq to use Syria and the surrounding region as a base for future operations, which will not only be of concern to Syria's neighbors (perhaps most notably Israel), but also Europe and the U.S.
The rebels are not the only belligerents in the conflict that have terrorists within their ranks. Hezbollah, which enjoys support from Iran, has been fighting on the side of Assad's regime.
Unfortunately for those that favor humanitarian intervention the conflict in Syria includes unpleasant elements on both sides.
What may happen is that the dilemmas involved in arming the Syrian rebels and the urge to intervene will prompt countries like the U.S., France, and the U.K. to intervene more directly. While the deployment of western troops on the ground in Syria remains unlikely it should not be surprising if some countries decide to execute an operation similar to what was seen in Libya, where a no-fly zone was put in place and NATO members carried out airstrikes.