The fears and tensions in the aftermath of September 11 created an unusual political climate in the US, in which it became possible for the government to lead an invasion without having to explain precisely why. Nobody seemed to quite know who or what was guiding the administration as it led the charge for war: was it utopian neo-conservatives trying to reshape the world in America’s image? Was it isolationist hawks trying to wipe out an old foreign foe? Was it oil-hungry Texans? Was it paranoid security advisers, regretful of their failures and with a new bent for pre-emption, no matter how distant the threat?

Years later, the war is far from over and the reasons for it are still not quite clear. Everyone seems to agree that the situation in Iraq is, at the least, a mess, but not everyone will agree that it had to be thus or that it will not be fixed, and there is still ample room on all sides for certainty and strong convictions. So, for those who want to argue, there are facts aplenty to be marshalled, stressed and convoluted. There has been good (the quick war, the removal of Saddam Hussein, the election turnout); and there has been bad (the insurgency, the Sunni boycott, Abu Ghraib, the lack of weapons of mass destruction). Pick up the Wall Street Journal and you will find a tendency to the good; pick up The Independent and you will find a tendency to the bad. But the predispositions have already been predisposed; the minds have largely been made up. Each person has his or her filter to let the facts drip through.