The doves in America need to speak up now to spare us war on Iraq

We have little choice now but to conclude that President George Bush has made up his mind to go to war with Iraq to oust Saddam Hussein. He has not himself said as much, and is unlikely to do so when he makes his next set-piece foreign policy speech, to the United Nations General Assembly, on 12 September. For the moment, the White House shelters behind its mantra that "no decision has been taken", absurdly blaming the media for a "frenzy" of speculation for which it alone is responsible.

But the language of the two policymakers closest to the President – indeed, the men who frequently give the impression of being in charge of US foreign policy – leaves little doubt. Vice-President Dick Cheney's speech in Nashville on Monday was the Bush administration's most cogent attempt to make the political case for swift action in response to the doubts raised by sundry Republican luminaries who served under the current President's father. Now Donald Rumsfeld has set out the moral case in terms that chime exactly with Mr Bush's views of good and evil, and his country's basic conviction that it is uniquely, indeed divinely, guided to be the former.

The Defence Secretary used a logic that brooked no argument as he poured scorn on America's unhappy allies, claiming that the rest of the world would come round to Washington's thinking: "When our country does make the right judgements, then other countries do co-operate." But, in any case, he added, "it is less important to have unanimity than it is to be doing the right thing".

Translation: the US is going ahead, whether the rest of the world likes it or not. Mr Rumsfeld then threw in a comparison that will sound especially ridiculous to the British ears that Washington needs to bend, likening Saddam Hussein to Hitler, and therefore George Bush to Winston Churchill. If only.

It is all very well for a senior diplomat from Saudi Arabia, in the front rank of the dissenters, to note that in Washington's debate on Iraq rhetoric is running far ahead of political reality. He is wrong. The rhetoric is creating the reality. The hardliners who clearly have the upper hand in the debate are engaged in a double game of chicken – with Iraq, of course, but also with America's reluctant allies, betting these latter will be too scared of the consequences to have Washington go it alone, and thus join in anyway.

After all, the Cheney/Rumsfeld camp points out, similar doubts were voiced when President Reagan took on the Soviet evil empire, when George Bush senior launched the 1991 Gulf War, when Bill Clinton decided to bomb Slobodan Milosevic out of Kosovo, and when this Bush attacked Afghanistan, once celebrated as a graveyard for foreign invaders. But everything was fine on the night, and so it will be with Iraq this time. Pluck up your courage and swallow the medicine, they urge reluctant allies. It doesn't taste as nasty as you think, and it will work wonders.

The real dispute in Washington now is not whether the US should attack, but whether it should do so alone or only with the blessing of the UN and with allies in the field. Mr Cheney laid out the unilateralist case, dismissing any return of weapons inspectors as a waste of time and insisting that the longer the delay, the greater the danger posed by Saddam. We desperately need the multilateralists to make their case and prevent the certainty of short-term military victory over Iraq from blinding the US to the potentially devastating longer-term consequences. Colin Powell, where are you?