[ClearCase_guy]

The US seeks instablity in the Middle East (this is what the Arab Spring is all about). The secular governments (such as Assad) need to be disposed of, so that the Caliphate can be restored. Sunni and Shiite, of course, do not get along, but I suspect there is a movement to unite the two groups and have Iran (Shiite) become dominant and gain control of the holy sites, displacing Saudi Arabia (Sunni).

As in the US, if the original power structure is torn down, a new power structure (based on Islamic fundamentalism) can replace it. Assad stands in the way of this, so the US helps ISIS. In the end, Iran needs to dominant, so the US helps Iran.

Obama plays both sides in an effort to strengthen the ultimate Caliphate.
It's a different take on what Reagan did -- he helped both Iran and Iraq in the 80s as they both fought each other. You play both sides if you have a long-term strategy that benefits from the ebb and flow.

[Pearls Before Swine]

The US seeks instablity in the Middle East ..... so that the Caliphate can be restored.

Obama and his inner circle seek that; the rest of the apparatus just follows along.