Apart from a Shia-Sunni bloodbath, the only one capable of stopping the ISIS is IRAN.
They have already moved in and have men in Iraq, and we can never be sure how much because of how they blend in with Shia millitias.
These are Pasadran of al quds brigades and are experts at insurgency and counter insurgency, and good at hiding them selves.
Trust me there could be far more already in Basra, and southern Baghdad.
I heard something about the mosul fall, apparently the Peshmerga and the Iraqi army defended Mosul, theIraqi army mostly sunni bolted and ran, some even joined ISIS. The Peshmerga fought and held on but where ordered to retreat as the situation was advantagous for the Kurda back a month ago.
Another thing is that Baghdad is now a Shia city, it used to be 40% sunni but now has about 10%,
they were ethnically cleansed a couple of years ago..
Allot of Sunnis will join ISIS to stick it to Al Maliki. The Iraqi army also doesn't get paid salary on time.
Iran really are the ones who can get rid of ISIS. Assad is winning in Syria due to the Iranian brigades and the general he has who has become his defacto chief in the war