Years After the Fall of Saddam, How Do Iraqis Look Back on the War?

It might well be that the war has ultimately given Iraqis a shot at democracy. But it also eliminated the region's most important check on the Islamic Republic of Iran. As Ignatius pointed out, Iraq is now a transit point for materials and pro-Assad fighters going into Syria: "It's a perverse consequence of history that we spent a trillion dollars and countless American lives to give Iran strategic advantage in the region."
It might well be that the "majority" of Iraqis feel better off thanks to the war. But even if so, that majority would certainly be dominated by Kurds and Shias, and comprise very few Sunis. And one of the major ongoing challenges that post-war Iraq faces is precisely: horrible sectarian violence.
It might well be, too, that ultimate responsibility for the to-date acute failures in building a democratic Iraq lay with Iraq's post-war leadership. But ultimate responsibility surely still lies with the United States for, at the very least not knowing who will fail to build a successful new state after the U.S. dismantles the old one.