Peter Bergen : Eric Harroun , a former American solider , was charged in 2013 with conspiring to use a rocket-propelled grenade in Syria , and he admitted to fighting with al-Nusra . U.S. may be reluctant on Syria 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 is also a major source of funding for Syrian rebels, which could complicate any future peace talks with Assad. He says group has shown ability to stage suicide bombings , threatens U.S interests .
Peter Bergen : U.S. may be reluctant on Syria 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 is also a major source of funding for Syrian rebels, which could complicate any future peace talks with Assad. He says group has shown ability to stage suicide bombings , threatens U.S interests .