As the Sunni group ISIS, an offshoot of al Qaeda, continues its roll through Iraq, Iran has deployed Revolutionary Guard units to the country. Iran, which is majority-Shiite, has invested time and money into making sure that post-U.S. Iraq was a Shiite-state. The dispatched units are to protect Baghdad, as well as Shiite holy cities Karbala and Najaf. Iran entering the fray just as Iraq is calling on the U.S. to intervene would create a bizarre historical moment, with the two longtime adversaries potentially fighting on the same side. "We've encouraged [Iran] to play a constructive role in Iraq," State Department spokeswoman Jen Psaki said.