How far will Russia go to help Syria liberate Idlib? From Patrick Lawrence at consortiumnews.com:
Turkey’s leader, who nurses dreams of some kind of neo–Ottoman restoration across the Middle East, is now on a reckless tear.

Russian President Vladimir Putin and Turkish President Recep Tayyip Erdogan at a press conference in Turkey, Dec. 1, 2014. (Russian government)
As Recip Tayyip Erdogan prosecutes his latest military intrusion southward into Syria, all the old mythologies about the Turkish president and the 9-year-old Syrian conflict are rehearsed once again, hopelessly threadbare as they are. The problem now is not the fog of war. The problem is the war of fog.
Let us be clear from the start, then, as to what has unfolded since last week and what will be the desired outcome. The Syrian Arab Army, a force for good, must not stop short of decisive victory in Idlib, the governorate in northwest Syria sheltering the last jihadist militias operating on Syrian soil. Russia, which is correctly (and legally) supporting the S.A.A.’s campaign, should try to avoid a direct conflict with a NATO member but should engage Turkish forces if there is no alternative.
NATO, breaking its own Article 5 covenant, will not come to the aid of a member nation engaged in so despicable an assault on another sovereign nation. I am not alone in holding this opinion. Don’t forget: Most NATO members are squeamish, mealy-mouthed Europeans who have given up the ghost in Syria.