Correlli Barnett: Flags fly, statues topple. But what are we fighting for?

Passionate ideology - from any side - is the last thing the world needs now

With all of Basra in British hands and much of Baghdad in American hands, with Iraq's oppressed Shia population exultant as Saddam Hussein's statues bite the dust, this is euphoria time. Commentators like me who predicted a prolonged messy struggle in the streets have been confounded. And certainly I could never have believed that Saddam would be so foolish as to deploy the Republican Guard in the open to be smashed by overwhelming US firepower.

Yet in this euphoria of victory, it is too easy to forget that war is not like a football final where the winning goal is to be cheered as an end in itself. War has a political purpose. So even while the cheering – and the looting – goes on, I would ask: what has been the US's true purpose in attacking Iraq?

Is it really about disarming Saddam of weapons of mass destruction (so-called)? Remember that prior to the war no direct evidence of his possession of such weapons had been offered, only inferences drawn from presently unaccounted-for items listed in old inventories. Given the known unreliability of even British bureaucratic record-keeping, were these circumstantial inferences really grounds enough to launch a war on this scale?

And what if the US occupation forces now fail to find such weapons? The cynics will say that this unthinkable contingency has already been provided for.

Or is the war to be justified on the grounds that Saddam had failed to comply with the precise terms of Resolution 1441 and its predecessors? The lawyers have had a field day arguing about the exact meaning of these resolutions. It is, however, clear that 1441 was itself a compromise because the French and the Russians would not swallow the original US draft embodying an automatic trigger for war. Anglo-American spokesmen were therefore wrong to claim that in signing up to 1441 the French and Russians were signing up to war to enforce it.

If, as Washington argued, Iraq did indeed stand in breach of 1441, this was surely a technical breach rather than a real threat, since Hans Blix's team of inspectors was working well and wanting to continue.

Is it really possible, therefore, that President Bush's Washington has smashed Iraqi cities and filled Iraqi hospitals with maimed civilians on the basis of a legalistic quibble? Or is the war to be justified on the grounds that Saddam Hussein is linked to 9/11 and/or al-Qa'ida?

No evidence has been produced to support either claim. Can it be that all the havoc wreaked by US firepower merely signifies revenge – miss-targeted and disproportionate – for the destruction of the World Trade Centre on 11 September 2001?

Or did Bush's Washington only go to war in order to topple a monstrous tyrant guilty of cruel oppression inside his own country, as implied by the cringe-making Hollywood-style codename for the war, "Operation Iraqi Freedom"?

As we witness the scenes of jubilation in Iraqi cities, it will be all too tempting to think that such a motive has been finally vindicated by Saddam's downfall. Yet of all the shifting reasons offered by Bush's Washington and Blair's London, this is surely the most dangerous in its implications, because it threatens the very basis of the present world order of sovereign states. We must remember that the United Nations was set up to prevent 1930s-style cross-frontier aggression. This rendered the 1991 Gulf War an entirely legitimate exercise. But what will be the potential consequences if nation-states may arrogate to themselves the right morally to judge other states, and then attack them in order to overturn their regimes and "liberate" their peoples?

After all, Osama bin Laden and al-Qa'ida morally judged the US to be a corrupt materialist society bent on enslaving the Muslim world, whence followed the attack on the World Trade Centre. However, al-Qa'ida is a terrorist organisation, not a state, and so its actions are illegitimate by any measure. But supposing the ayatollahs in Iran, who have made the same moral judgement on the US, now sought by whatever violent means to overturn the political system in that country? Would that be legitimate? Or if North Korea did the same, on the score that the United States represented the capitalist system ripe for revolution?

Or is the action of judging other states and then attacking them only legitimate if, like the US, you possess overwhelming military power, and can attack unscathed?

What therefore I find truly alarming about this present conflict is the crusading sense of a moral mission which drives Bush's Washington and our own pious Prime Minister. It seems to me as a strategic historian that the last thing that our fraught world needs is passionately-held ideological conviction of any kind – and especially when that conviction is conjoined either with terrorism or with overwhelming military power.

So the question remains; what is this war really about? And no matter the true answer, what will be the war's legacy, in Iraq, in the Middle East in general, and throughout the wider world?

Correlli Barnett is author of 'The Great War' (BBC Books)