Petraeus: The Islamic State isn’t our biggest problem in Iraq - The Washington Post

"The most significant long term threat is that posed by the Iranian-backed Shiite militias. If Daesh is driven from Iraq and the consequence is that Iranian-backed militias emerge as the most powerful force in the country — eclipsing the Iraqi Security Forces, much as Hezbollah does in Lebanon — that would be a very harmful outcome for Iraqi stability and sovereignty, not to mention our own national interests in the region."