Defending against itself.

Reporter Lara Logan

The insurgents have seized several cities and are threatening Baghdad. Fighting under the banner of the Islamic State in Iraq (ISIS), they regard Iraq's Shia majority as "infidels".

Iraqi security forces, bolstered by Shia and Kurdish militiamen, holding the advance by Sunni militants north of Baghdad and have retaken a number of towns that had fallen to the rebels. One cleric, sitting with a driver and bodyguard in an expensive four-by-four vehicle, said they were prepared to fight to the death and "splash their blood" to rid Iraq of the ISIS "terrorists".

Iran says it could be prepared to work with the US to fight Sunni insurgents in Iraq.
Sunni and Shia name each other as Infidels and terrorists. They are ready to fight, with religious people to justify the killing, creating a volatile situation.

Iraq has oil, and all the eyes and the fights are on it. Reduce the need for their oil, the region becomes more peaceful.

Just a thought