It's not a double-cross to fight terrorists, the enemies of your ally. It is highly questionable to be funding and arming jihadists and terrorists though. Seems to me Obama and certain ill factions in our government are dismayed that the Russians might annihilate their terrorist suppliants. Still though, I don't think the Russian uptick will be enough to stop the fall of Assad. Even moreso I do not think they will be able to stop the Islamic State for now. Perhaps this is why the Russians have avoided going toe to toe with the strong one of the islamic heathen and instead have focused on the weaker jihadists and terrorists. We shall see though.