The national vote, due to be held in January, is seen as a crucial test for Iraq, the world’s 11^th largest crude oil producer, as it emerges from the sectarian carnage unleashed by the U.S. invasion in 2003.

“This agreement advances the political progress that can bring lasting peace and unity to Iraq and allow for the orderly and responsible transition of American combat troops out of Iraq by next September,” Obama said at the White House soon after the Iraqi parliament approved the law.