Realtime is right on this one. Sunni won't fight other Sunnis especially when the leader is Shea.The Iraqi Army cannot fight. It is a trainee Army, taught to think the Americans will do the dirty work for them.
Bush taught them that in the 6 years after he disbanded the original Iraqi Army, which is now fighting for IS.
That is why IS has been successful.
Maliki had purged the army of Sunni commanders. He made a mess for himself and is aligned with Iran. The only ones worth getting involved for are the Kurds who are very pro American.