The peace movement may have lost the war, but it is fighting on. Indeed, it even seems to have won the odd battle. For in ways that few could have predicted, the anti-war campaign has helped shape the way the war itself is being fought.

Start with the evidence that the peace camp is refusing to wave the white flag, in Britain and beyond. As promised, the first day of military action brought protesters on to the streets in every major city in the land. In London, police found themselves stretched to capacity as they dealt with one sit-down protest after another, sprouting all over the capital. Yesterday, peaceniks got on their bikes, holding up traffic in London and Sheffield. Today there will be another anti-war demo in London. No one expects the gargantuan figures achieved on February 15, but the commitment is still there.

As it is around the world. US embassies have been besieged with protesters from Quito to Bangkok, Buenos Aires to Cairo, with a candlelit vigil in Berlin and a general strike in Athens. The German protest was led by schoolchildren, a sign that the phenomenon of youth protest which has surprised so many here is not confined to Britain: if anything, this war seems to have politicised a whole new generation. Those kids who skipped school to protest against a faraway war, whether in Bristol or Berlin, will never forget the experience.

The mood at some of the demos is doubtless one of anger but also gloomy resignation. After all, the peaceniks lost the big campaign: they did not, despite their efforts, stop the war. They could be forgiven for feeling like New York Times columnist Nicholas Kristof, who wrote yesterday: "Those of us who have opposed this war need to recognise that we lost the debate. It's time to move on."

No wonder American peaceniks feel that way: according to one poll yesterday, more than 70% of Americans back George Bush's decision to go to war against Iraq. But public opinion outside America, including in Britain, breaks the opposite way. Peace activists outside the US have no reason to feel they "lost the debate". In many ways, they won it.

Which brings us to the strange, unexpected influence the anti-war effort seems to have had on the first stages of the conflict. Last night appeared to mark, at last, the beginning of the long-threatened "shock and awe", a ground-quaking, sky-burning display as America pounded Baghdad from the air. But the start, at least, of Operation Iraqi Freedom was not like that; it did not come as previously advertised. Instead, it seemed to have been devised with one eye on the concerns of the anti-war movement. The campaign began not with "shock and awe" but a subtler knife, aimed at the surgical decapitation of Saddam Hussein and his regime. One night's bombing of Baghdad lasted no more than an hour. The terrifying spectaculars threatened by Rumsfeld and the boys, reminiscent of the fireworks of the first Gulf war, only materialised last night.

There could be a stack of explanations for that initial deployment of the short, sharp blow. US planners were embarrassed by their performance in Afghanistan, where they managed to drop bomb after bomb - and still miss Mullah Omar and Osama bin Laden. This time they wanted to be nimble and flexible - able to react to up-to-the-minute intelligence, like the tip-off of Saddam's whereabouts which prompted Wednesday's opening assault - rather than simply flatten Iraq only to see their man get away. (They still don't know for sure, incidentally, who they hit on opening night. The US even got Saddam's former mistress, Parisoula Lampsos, to examine tapes of the Iraqi dictator's dawn TV address, bragging of his survival. Ms Lampsos has correctly separated Saddam from his lookalikes more than a dozen times, say US sources, but she insists the man in the Thursday broadcast was not him.)

But there may be another motive for the initial preference for short-and-sweet over shock-and-awe. The US might have wanted to avoid a wave of worldwide revulsion. A series of tight, well-aimed strikes at the regime would have confounded the global fear of colossal Iraqi civilian casualties. It's as if Washington had heard the peace movement's objection to this war - that too many innocents would die - and was attempting to heed it. (Now the US can, at least, say it tried its best, but that it didn't bring instant results.)

The irony here is that the architect of the new, more targeted approach was the hated Rumsfeld, while the doctrine he was effectively replacing - the
belief in immediate, "overwhelming force" - was first articulated during Operation Desert Storm by Colin Powell, darling of the European peace camp. "[We'd like] a lot of Powell and very little of Rumsfeld," requested the Spanish PM of Bush earlier this month. In the first 48 hours of battle, that wisdom was apparently turned on its head.

The Americans listened to their critics in other matters of strategy, too. A loud complaint in the first Gulf war, and in every conflict since, was that Americans fight "cowards' wars". They prefer to drop bombs from the safe distance of 15,000ft rather than expose themselves to the danger of ground battle, said the critics. That refrain was a clamour in the Kosovo war of 1999, and heard in Afghanistan in 2001, too.

This time the Americans are doing precisely what was demanded of them: risking their own necks by sending in ground forces. The speed of the land war, with desert convoys rolling into southern Iraq from Kuwait almost immediately, stunned the armchair generals, who assumed the US would do a whole lot more "softening up" from the air first. Ground troops might all be part of Rumsfeld's new, more light-footed style. It's also true that September 11 has fundamentally changed US attitudes to casualties: now, say many Americans, no price is too high to fend off a potential threat. What's not in doubt is that anti-war voices have changed the terms of debate.

There are smaller examples, too. "It's all about oil," opponents of a military attack have chanted, a tad simplistically, from the very beginning. The claim was dismissed as paranoid nonsense, but it obviously stung just enough to make both London and Washington keen to deflect it. Why else have both moved swiftly to announce that Iraq's oil wealth will be held in a UN trust, to be spent only on the Iraqi people themselves? The peace movement made it impossible for the US, in particular, to do anything else.

Critics have ralied against Washington for its gunslinging unilateralism, lambasting the US for playing the lone ranger. So the first sentence of George Bush's TV address on Wednesday night referred to "coalition forces". Of course he spoiled the multilateralist feel of the phrase by preceding it with "on my orders" - suggesting he is in charge even of the British army - but the thought was there. And perhaps the clearest proof of the anti-war camp's efforts came from our own prime minister: "I know this course of action has produced deep divisions of opinion in our country," he said, just seconds into his own TV message to the nation. No leader wants to go into a war admitting such a thing. But Blair had no choice. As with much else, the peace movement has changed the landscape for this conflict - and the men of war are having to deal with it.