There are, however, a credible array of reports that the Islamist role in the opposition remains significant and worrisome. Chairman of the Joint Chiefs of Staff Martin Dempsey voiced these concerns in a letter to Rep. Elliot Engel last month. But he appears to have been echoing analyses from government intelligence. At the Aspen Institute’s Security Forum in late July, David Shedd, the deputy director of the Defense Intelligence Agency, warned that groups affiliated to al Qaeda “have grown in size, grown in capability and ruthlessly grown in effectiveness. Their ability to take the fight to the regime and Hezbollah in a very direct way has been, among those groups, the most effective.” They “would not go home” if Assad were ousted, he said, but will “fight for” a place in a post-Assad Syria.

British intelligence experts have also warned of growing extremist influence in Syria’s opposition. Charles Lister, an analyst at IHS Jane’s Terrorism and Insurgency Centre, wrote recently that “the most notable trend in Syria in 2013 has been the increasing strategic supremacy of Islamist groups, particularly in the northern half of the country. Every major opposition military victory since September 2012 has been Islamist-led.” He concludes that “there is a power shit underway within the Syrian insurgency and it is not one that will be welcomed in western government circles.”

There have been also repeated reports of disarray within the Free Syrian Army and its coordinating group, the Supreme Military Council (SMC), that belie the Obama administration’s current optimism about the opposiiton. In a report in late August, Justapha al-Sheikh, a defector from the Syrian army and a member of the FSA, cast doubt on the group’s strength. The West’s lack of support has turned the FSA, Al-Sheikh said, into “an empty address without any real substance,” while leaving Islamists as “the real power on the ground.”