The discontents, a motley band of floating voters in search of someone to support

We are probably quite numerous. We may even be a sufficiently large group to affect the result of the next election

Iraq will determine how I vote at the general election. I know this already even though it will probably be at least 14 months before we are called to the polls. As far as economic policy is concerned, the differences between the parties are pretty small, technical questions dressed up as political choices. I don't think I need to bother about them. Iraq is what matters.

How many are we, the Iraq discontents? Some of us will want to punish Tony Blair, the Prime Minister, for sending British soldiers to their deaths on a false prospectus. In earlier ages, before British politicians lost any sense of responsibility for their actions, the prime minister of the day would have resigned. Others will take a broader view, arguing that the whole notion of a "war" against al-Qa'ida is wrong. The Madrid bombings, for instance, were terrible crimes, not acts of war; terrorists are criminals, not warriors. There will be those who object to British support for the new American policy of pre-emptive strikes against so-called rogue states, arguing that intelligence agencies are insufficiently skilled to provide the necessary proof. Many will go to the polls believing that Parliament and the British public were conned into supporting the war against Iraq. Intelligence was indeed sexed up. Material favourable to the Prime Minister's views was published while adverse advice was left in the drawer. See what the Spanish electorate did when it felt cheated.

Given the range of issues that Iraq has raised, we discontents are probably quite numerous, a new type of floating voter, more concerned with international security than with domestic issues. We may even be a sufficiently large group to affect the results of the next election. Don't forget that two million people participated in the great anti-war demonstration in London and elsewhere in March last year. Two million voters is a lot. Since then every marcher has seen his or her fears realised. At the time, their protest - "not in my name" - was ignored. Now the demonstrators know they were right. And others must have come to wish that they too had protested. In fact if just five out of every hundred electors cast an Iraq protest vote, then the outcome would be substantially different from what otherwise might have been expected. I don't think any of the party leaders have yet grasped the importance of Iraq as an election issue.

Tony Blair alone has the power to remove the question from the election debates. He could take responsibility for the erroneous intelligence assessments; he could agree that the coalition had handled Iraq so badly since military victory that al-Qa'ida has been given fresh opportunities rather than suffering a reverse. He could confess that the world had become a more dangerous place. He could argue that we require more rules governing international relations rather than fewer. He could go to see the war widows and say that this should not have happened.

He could admit that he was wrong. Or he could resign.

That would settle the matter. British politics could go back to business as normal. We could at last "move on" without a backward glance. For, if I may guess at the opinions of other Iraq discontents, we are not asking that British troops be withdrawn from Iraq prematurely. We would not set a deadline as the prime minister elect of Spain has done. We are not seeking an early exit. We fully accept the duty imposed upon us by the invasion. Indeed I would not demur if a coherent argument was presented that more British troops were required. We wish to be resolute.

As a matter of fact, on the morrow of Gordon Brown's triumphant Budget speech, there would not have been a better moment for the Labour Party to dump Tony Blair. It would be one of the least risky changes of leader that any governing party has carried out. There would be no great drama or uncertainty as there was over the fall of Margaret Thatcher or Anthony Eden. In those cases, whether there would be a battle for the crown and who would win could only be guessed at.

But Gordon Brown is the certain successor of Tony Blair. He is all but prime minister in name anyway.

What should the discontents do if Mr Blair stays on at 10 Downing Street? Supporting Michael Howard should have been an inviting choice, even though the Conservative Party voted in favour of war. After all, it may form the next government. It could take on board more easily than the Prime Minister that the war had been an error. It could say: "yes, we were wrong. We were misled" and then show us convincingly what to do next in Iraq. After all, the architect of the Tory pro-war policy has been sacked. Mr Howard is a new leader. But I wrote "might have been", because Mr Howard blew it as far as I am concerned with his speech to the News International conference in Mexico last Friday. What he said about Iraq might have been written by Tony Blair. He is absurdly, blindly unrepentant. He continues to speak the misleading language of war rather than crime. And he said: "We must be ready to take pre-emptive military action, in exceptional cases, as a last resort." No, no, never.

With his unnecessary words Mr Howard completely closed the door on the Iraq discontents. It was remarkably uncanny of Mr Howard. For all his brilliance at the dispatch box, he cannot recognise that the British public hasn't said that it agrees with the novel doctrine of pre-emptive military action and almost certainly would not do so if the consequences were fully spelt out - that is, if Iraq hasn't already made the counter argument as eloquently as could be. A nation that is very law abiding is unlikely to welcome anarchy in international relations. What is it about the Tories? They let Gordon Brown stamp all over their domestic policy in his Budget statement while they loyally stand up for Tony Blair's discredited foreign adventure.

Which leaves the Iraq discontents with Charles Kennedy and the Liberal Democrats who opposed the war from the beginning. In this, the Lib Dems are also discontents. But let us merely note at this stage, with many months to go before the general election, that in his speech at the Southport conference yesterday, Mr Kennedy spoke well about Iraq. Mr Kennedy said: "I don't believe it's helpful to use the rhetoric of war to describe what is happening ... Why? Because al-Qa'ida is not a nation. It's a fanatical group of murderers who deserve to be treated as such." Correct.

As to pre-emptive strikes, Mr Kennedy noted that "A doctrine of pre-emption could be a licence for nations to intervene beyond their territory - whether or not they are under threat themselves ... It would be naïve to believe that only the good guys - the democracies - with world peace at heart - would invoke such a doctrine". Again correct.

But why am I not more enthusiastic? Because it is too soon. Many things can change before we go to the polls. So I content myself with saying that as matters stand the Lib Dems look the most likely home for the Iraq discontents.