In the years leading up to World War II, the Soviet Union and Germany appeared to be getting along famously. In fact, such dealings led to the partion of Eastern Europe in 1939 between the two.
However, neither country was truly concerned with true cooperation. Both had the ultimate aim of laying the other low--two totalitarian forces which were in a marriage of convenience.
The same thing is happening here. I do think, however, the Left is on the losing end of the alliance. And, ultimately, (much like the leftists in WWII), a clamor will be raised in the MSM to enter into battle against Muslims at the cost of blood and treasure by folks who had no belief in the totalitarian goals of the Left or the Muslims.
Gee, I wonder what the caliphate will do with drug users, gays, transgenders, communist idealogues and eco-freaks when they come into power?