For some, sectarianism in Iraq appeared like a summer storm, which quickly passed once the “surge” of US troops became American strategy in 2007. But even the colossal mistakes of “de-Baathification” (the dismissal of all Iraqi officials who had been members of Saddam’s Baath Party) and the decommissioning of the Iraqi army – measures so foolish that nobody now admits to ordering them – cannot fully explain Iraq’s continuing political crisis.