The Syrian conflict has taken many unpredictable turns over its terrible four years. But the developments this week are some of the most concerning so far.
Syria has always been not only a domestic civil war but also a place where regional powers have struggled with each other to promote and prop up their own interests. This seemed to be tolerable to much of the West when the countries vying with each other in Syria were Iran, Saudi Arabia, Turkey, the Gulf States and others. But the arrival of Russia in an open, rather than covert, manner changes things completely.
Because Russia is now openly involved and engaged in seeing the civil war to the end they have always wanted, and just as Turkey has used air strikes purportedly against Isis to in fact engage in their war against the Kurdish PKK, so Russia, under the guise of pursuing Isis, has clearly been carrying out its own sectarian, pro-Assad business.