Keeping the two in equilibrium over the past 20 years - my entire politically conscious lifetime - has meant lowering standards to maintain a sense of perspective. Unsustained by the prospect of victory, optimism becomes little more than wishful thinking and realism curdles into defeatism. "The greatest tool in the hands of the oppressor is the mind of the oppressed," argued the late South African black consciousness activist, Steve Biko.

In the 1980s, Mrs Thatcher told us there was "no alternative", and though we fought anyway, deep down some of us actually believed it. A culture of protest emerged that has been informed more by duty in the face of the inevitable - "We should oppose this even though we know it is going to happen" - than determination in the pursuit of the possible - "We must stop this before it happens". Losing has become a habit, being in a minority has become a mindset.

As the military matériel stacks up in the Gulf, poised to bomb Iraqis into shreds, we need a rapid and radical change in thinking. Unlike the last Gulf war, the Kosovo war or the ongoing war in Afghanistan - in fact unlike any war in recent times - those who oppose Britain's participation in the western bombing of a poor country are part of a large majority. Between 52% and 72% of the public in Britain oppose Britain's involvement in the bombing of Iraq. This is a war that we can stop before it starts. Opposition to it is popular. We must work out how to make sure it both persists and prevails.

The case against the bombing has been made by others on these pages, including Roy Hattersley today. Given the volatile situation in the Middle East and the certain power vacuum left by Saddam's ousting, even the ramifications of a succesful mission could be catastrophic. Answers to the key questions - why him? why now? and what next? - are either unavailable or unconvincing.

You do not have to be particularly progressive to agree with or understand this. Far from it. Both the pacifist and the military strategist can see the barbarous folly of going to war. The array of people who are against action without the backing of the United Nations - from the Archbishop of Canterbury to Bill Morris and from Storming Norman Schwarzkopf to Nelson Mandela - itself tells a story. On just about every front - moral, legal, military, economic, human, strategic - bombing Baghdad would be an utter disaster.

To sense the breadth of opposition we need look no further than Germany where, according to pollsters, Gerhard Schröder's anti-war stance has done more than anything else to reverse the flagging fortunes of his campaign to remain chancellor. His rightwing challenger, Edmund Stoiber, has resorted to what has been one of Europe's most popular policies of late - bashing foreigners. "Four hundred million people are threatening to come our way," he told crowds in Wiesbaden on Thursday. "We must prepare ourselves."

However, with as many as 80% of Germans against the war, according to the head of one polling institute, Schröder has decided there are more votes to be gained to his left than to his right. "Germany has no reason to allow itself to be lectured by others," he told cheering crowds at a rally in the University of Munster last week. "On the existential questions that decide general politics the decisions are made in Berlin - in Berlin and nowhere else."

Having trailed for most of the campaign, Schröder is now in front. The forward march of the right in Europe, it seems, will be obstructed not by pandering to popular prejudice over immigration - à la David Blunkett - but by confronting American military hegemony. Germany's particular history gives it a deeper pacifist current than the rest of Europe. None the less, the strength of public opinion in Britain and America has made a difference. US president George Bush may have strode to the podium of the UN with the arrogance of an emperor and the ignorance of a knave last week, but he would not even have bothered if he didn't think he had to. Similarly, Blair would not have recalled parliament for next week or brought forward the publication of his dossier if he did not feel pressured.

None of these steps, however, suggests that either of these leaders is seriously considering peace. The extent of their concession to electorates who feel no threat from Iraq and have no desire to see innocent Iraqis killed, is that they are moving towards war more gingerly. They do so in the hope that the closer we come to the edge of conflict the more likely we will be to buckle under the weight of the inevitable.

So the fact that the polls are with us at present is heartening, but little more than that. Now we must make them count - transforming passive discontent into active opposition. We could begin by widening the debate to encompass the domestic agenda. During last year's election campaign we were told the government's priority would be the delivery of improved public services and we were lectured on the importance of prudence in the management of public finances. What is prudent about spending up to £4bn on a war few people want? Why should we have to wait for teachers, trains, hip replacements and heart valves because Bush won't wait for a diplomatic solution and Blair won't stand up to him?

There will, of course, be meetings, petitions and marches - like the one in London on September 28. But this week, ahead of the recall of parliament, there must also be letters, phone calls, emails and text messages to MPs, local newspapers and radio stations. Wars do not stop themselves. They are prevented by the mobilisation of large numbers of people, each of whom does what they can. If the bombs drop then, yet again, they will be in our name and paid for by our taxes.

In recent times "Stop the War" has been a useful and commendable slogan - three words that fitted on a placard and rallied the faithful. This time it is a distinct possibility. The difference between wanting it to happen and making it happen may well be believing that it can happen. And then doing something about it.