Peter Bergen : US may be reluctant on intervention due to role of al Qaeda - linked group . Al Qaeda 's harsh rule in Iraq precipitated the 2006 `` Sunni Awakening '' in which Iraq 's Sunni tribes rose up against the group . He says group has emerged as most effective rebel force and helps fill social needs . Bergen : Al Qaeda 's Syrian affiliate attracts the most foreign fighters in conflict . He says group has shown ability to stage suicide bombings , threatens U.S citizens .
Peter Bergen : US may be reluctant on intervention due to role of al Qaeda - linked group . He says group has emerged as most effective rebel force and helps fill social needs . Bergen : Al Qaeda 's Syrian affiliate attracts the most foreign fighters in conflict . He says group has shown ability to stage suicide bombings , threatens U.S citizens .