Peter Bergen : U.S. officials have long suspected that al-Nusra was really , in part , a front for Iraqi jihadists who had crossed the Syrian border to join the fight against Syrian President Bashar al-Assad . The announcement of cooperation between Syrian rebels , al Qaeda is worrying . He says it gives al Qaeda an opportunity to demonstrate that it is still relevant . The insurgent group , al - Nusra , is the most effective of the rebel groups in Syria , he says . Bergen : The Obama administration has been right to focus deliberately on aid to rebels .
Peter Bergen : The announcement of cooperation between Syrian rebels , al Qaeda is worrying . He says it gives al Qaeda an opportunity to demonstrate that it is still relevant . The insurgent group , al - Nusra , is the most effective of the rebel groups in Syria , he says . Bergen : The Obama administration has been right to focus deliberately on aid to rebels .