Heres my take after a bit of informed research from both reputable leftwing and right wing sources (hard to find but there are a select few)
Theres been a stand off for a while due to Obama politics and Russias aggressiveness in maintaining its oil contracts and infrastructure with Assad.
Consensus appears to be that the US and the Saudis (the latter of which are suprisingly coordinating local but large anti govt forces) have basically told Russia, Iran and Assad enough is enough.
The US have called Putins bluff. If they want to back Assad for oil theyll have to fight with the biggest dog in the yard - the US and its allies.
As a courtesy to the Russians, they were told in advance of the attack in case they had russoans on the ground. Basically run for your lives comrades.
Russia have pulled their heads in. They wont go to war. Assad is finished.
Its understood Assads entire airforce has been destroyed.
Assad is finished.
The plan is to deal wiith ISIS as part of the overall overthrow but it sounds like Assad is the first goal.
To the victors go the oils. Iraq all over again with a few twists.
