(CNN) -- The United States has inflicted damage on one enemy in Syria with the airstrikes it launched against ISIS. But it may also be helping another foe: the regime of President Bashar al-Assad.
Rewind a year, and it was al-Assad's forces, not Islamic militants, against which President Barack Obama was weighing military action. Those strikes never happened, due in large part to a timely diplomatic intervention from Russia.
Now, warplanes from the U.S. and Arab nations are pummeling the stronghold of ISIS, a group that has gained global notoriety for its brutal tactics and ruthless treatment of people who don't follow its extremist version of Islam.