Can Historic Adversaries Become Unlikely Allies?

Refugees continue to stream out of Syria by the tens of thousands, creating an international crisis, but efforts to restore order are more confusing than ever. Despite the al-Assad regime's history of torture and murder in Syria — including the barrel-bombing of its own people -- the Obama Administration has limited involvement in that country's civil war to an air campaign and the training of a few so-called "moderate" rebels. Now Russia — which has supported Assad — is sending in military equipment and some troops. But the worst nightmare for either power is a failed state taken over by ISIS. Is there a possibility of finding common ground?