The New York Times: Reports how striking IS helps the Assad Regime, the article notes the following, " ..a mounting concern for the White House is how to target the Sunni extremists without helping President Bashar al-Assad. "
Lets Get Real:
Odd bed fellows are no that unusual when it comes to WAR, in World War One, you had Republican France and Tsarist Russia as allies against Germany, then in World War 2 there was the alliance between Hitler's Germany and Stalin's Russia before Germany invaded Russia. Then Russia become an ally of the Democratic West, e.g the US and the British. What ever rhetoric that is used by the Oval any attacks by the US on IS will help Assad in Syria. One would presume there are back channels to Assad, the Oval would not want Assad's air defences to shoot down a US plane when it is attacking IS. Of course the back channel will be secret, nothing formal for a Congressional Committee to request an investigation. Wars are a dirty business, not just the fighting, your allies can be a mixed bag of relationships, even if you do not want them, the US could do a twin strike, hitting IS and Assad, that would be a brave and bold decision by the Oval.