"The popular-uprising-turned-armed-rebellion in Syria is in its third year, and seems poised to continue, with the government and a bewildering array of militias locked in a bloody struggle of attrition. The Obama Administration has signaled a pending expansion of U.S. civilian and military assistance to the opposition in the wake of the U.S. intelligence community's conclusion that President Bashar al Asad's forces used chemical weapons in limited attacks in recent months. U.S. officials and many analysts have asserted that President Asad and his supporters will be forced from power, but few offer specific, credible timetables for a resolution to the crisis. Further escalation in fighting or swift regime change could jeopardize the security of chemical and conventional weapons stockpiles, threaten minority groups, or lead to wider regional conflict. Opposition forces are formidable, but regime forces, backed by Hezbollah fighters and Iranian and Russian material support, have initiated successful tactical counteroffensives in recent weeks. The Syrian military continues to use air strikes, artillery, and pro-government militias in punishing attacks on areas where rebels operate. Some members of Syria's Sunni Arab majority and of ethnic and sectarian minority groups view the conflict in communal, zero-sum terms. U.S. officials believe that fighting would likely continue even if Asad were toppled."
CRS Report for Congress, RL33487