Well, Putin is cunning, like a hungry wolfe.

If he wipes out all the less insane forces and it's just ISIS and Assad then he will force the West to back Assad - thye only Western play here is to try to crush ISIS before Putin crushes the other factions.

Of the Four Great Powers within NATAO Obama is disinclined to get involved and be seen as a "war monger" when he's looking to his legacy, Cameron is otherwise occupied with Domestic issues, Hollande is a fool and Merkel likely does not care overmuch, she'd rather take in the resulting refugees and distribute them throughout the EU thereby enhancing German standing that way.

Things were different in 2011 when the British and French governments were looking to assert themselves on the world-stage and Cameron and Sarkozy were of a mind on this sort of thing.

So I predict that by the time the West wakes up Putin will have pretty much achieved his aims and we move closer to war in Central Europe.

Yay.