Reports are growing of a sharp increase in the number of extremist groups operating in rebel-dominated areas of Syria. This has raised eyebrows in Washington, where policymakers continue to grapple with the question of how to support the opposition without inadvertently helping jihadists expand their destabilizing impact across the Middle East. These concerns are growing among Syria's neighbors as well.
During a recent visit to Syrian border regions from southern Turkey, I spoke with armed and civilian opposition leaders about the extent to which extremist groups like the Islamic State of Iraq and al-Sham (ISIS) and Jabhat al-Nusra (JN) have penetrated their ranks. I also asked them what kinds of measures the opposition should take to prevent these groups from gaining a permanent foothold or exploiting the current crisis over the regime's use of chemical weapons (e.g., by disrupting international efforts to destroy those weapons). As enumerated below, their answers indicate that mainstream rebels have a number of options for reining in extremism while bolstering the overall effort to force Bashar al-Assad's departure. And many of these options offer good opportunities for U.S. engagement...