Could the US and Iran work together in Iraq?

Iraqi Shiite tribesmen brandish their weapons as they gather to show their willingness to join Iraqi security forces in the fight against Jihadist militants who have taken over several northern Iraqi cities, on June 17 2014, in the southern Shiite Muslim shrine city of Najaf.

Could the US and Iran work together on Iraq? US and Iranian officials in Vienna this week for negotiations over Iran's nuclear program met Monday to discuss Iraq.

The crisis in Iraq is deepening as militants from the Al Qaeda splinter group the Islamic State of Iraq and Syria (or ISIS) continue their advance toward Baghdad.

The deteriorating situation in the country is a great cause of concern for two unlikely allies: the U.S. and Iran. Although both sides have ruled out any joint military operations, U.S. and Iranian officials meeting in Vienna this week for negotiations over Iran's nuclear program did also talk on Monday about the situation in Iraq.

Ken Pollack, a senior fellow in the Saban Center for Middle East Policy at the Brookings Institution, joins Take Two to discuss how Washington and Tehran might collaborate on Iraq.