Adrian Hamilton: Why did so many people support the war in Iraq?

In all the discussion of the anniversary of our invasion of Iraq, one question has yet to be asked. Why is that so many people went along with it in the first place?

In one sense, the answer is obvious. The British public has always supported wars at the beginning, before their cost becomes apparent. Whether it was the Victorian adventures in the Sudan, Ethiopia and the Boer War, the sending of troops abroad has always been accompanied by flags, cheers and bunting. That is until the Second World War, when the country itself was threatened by invasion.

But then that is not the atmosphere in which the Iraq invasion took place. The extraordinary thing about this war was that it took place almost without public rejoicing. Millions took to the streets to protest. But there were virtually no demonstrations in support nor an atmosphere of much enthusiasm in Parliament. MPs and commentators supported the war because they supported the Prime Minister. In that sense, the Iraq venture was almost unique in British history in that it was one man's war – Tony Blair's. If he had not insisted on it, there would have been few calls from others to go ahead.

That doesn't explain the poverty of the pre-war parliamentary debate, particularly when you compare it to the Falklands debate, when the enthusiasm for invasion was much more vigorous and widespread, but when every MP standing up to talk felt it incumbent to discuss the issue in grave, and even moral, terms and to consider the options.

It did not happen this time partly because Parliament and the media no longer "do" options. With large parliamentary majorities and the decline in the advisory role of the civil service, there is no discussion of alternatives and wasn't in this case. Even those who favoured invasion as a means of getting rid of Saddam Hussein never looked into what alternatives there could have been, let alone took any interest in the appalling disaster that was the sanctions regime on Iraq over the previous decade. There were voices from the inside warning of the dangers, but in the general mood of war acceptance they were easily ignored.

There is a generational point, too, to explain the contrasting tenor of the Falkland and Iraq debates. New Labour and the post-1997 intake was filled largely with what might be called the "jammy generation", a group that on the whole had had life very easy. Not a few had been parachuted into their seats, most had come from a background in politics, media, advertising and research with a political career in mind. They had views on economics and society, but no particular sense of what was right and wrong in the big judgements. Effectiveness is what mattered and it is still in terms of effectiveness that the Iraq war is almost exclusively discussed today. The people on the demonstrations thought it was a matter of principle and morality. The people inside the Commons, with a few honourable exceptions, did not. Even the influx of women MPs, which some had hoped might alter the framework of debate, didn't and it wasn't only because, being new to the game, they were over-anxious to play by the male rules. The strongest voices against the war among women came from the older generation of Mo Mowlam and Clare Short, not Blair's babes.

But the main reason that so many went along with the Iraqi venture was that they felt no reason not to. It all seemed so easy and so apparently costless. No one expected many casualties, nor a huge burden on the taxpayer. The downside risk was not that we wouldn't win but that we would win too easily and that anyone who opposed the war would thus appear cowardly and anti-democratic. And in their way of thinking they were right. The occupation is now seen as a terrible failure, but the overthrow of Saddam was achieved at relatively little cost. The loss of British lives, in Iraq and in Afghanistan, has been pretty much taken for granted. The same with money. The figures on the expenditure on Iraq and Afghanistan have risen, but at no point in any Budget have they been sufficient to be treated as a constraint on other expenditure.

Of course, the experience of Iraq has put people off the idea of humanitarian intervention. But the main impact has been on the Iraqis themselves, rather than people back home, except in terms of occasional terror.

That is what worries me. I fear the British, in their hearts, still believe our military is second to none and that we can win any war with ease and at not much cost to ourselves. We still have every right, and the overwhelming military superiority, to intervene where we think it fitting; it was only that we didn't get the post-planning correct on this occasion. Next time it happens, Parliament will go along with it, just as it did five years ago.

a.hamilton@independent.co.uk