Al-Qaeda in Iraq is badly destabalized at the moment. It lost its center of gravity amongst the Sunni Tribes. The major threat in Iraq has become Iran. So the US must shift its strategic focal point to counter this new threat.
Belmont Club notes that Petraeus explained few specifics of his plan to deal with Iran.
US forces have traced the transportation and communication routes from Iran to Iraq. A central hub is the border town of Zurbatiya, where most of the traffic flows through. The US is building a military base at Zurbatiya to intercept contraband, while moving to take down the JAM before Iran can build it up into a Hezbollah quality force. Petraeus reported that the Iranian Quds Force may have just withdrawn prior to the coming anti-Iranian offense in Iraq.