Leading article: Three countries, two discredited leaders and one disastrous mistake

Iraq has made Mr Bush and Mr Blair isolated figures, before their home audiences and on the global stage

This was the week in which the costly folly of the Iraq war was finally made manifest, even to those hitherto least inclined to see the truth. Perhaps by coincidence, it was also the week in which the number of US and British lives lost passed the number of those killed on 11 September 2001. Not that this is all about numbers: it is about ruined lives, ruined families and ruined countries. It is also about honesty.

But in the overall equation the number of coalition dead is indicative, because it is not something that can be guessed at, massaged or reclassified with a view to making the overall picture look better. The balance sheet for those who invaded Iraq has now slipped incontrovertibly into the negative.

Would President Bush, we wonder, have been so confident about invading Iraq had he known in advance the likely cost in American lives - or the cost to his own political fortunes? On this side of the Atlantic, the Prime Minister still insists that he believes the invasion was justified because it removed Saddam Hussein, and Saddam - even without WMD - was still a threat to the world. But, as was painfully clear at this week's Prime Minister's Questions, the war is eating away at what credibility he retains.

Iraq has made Mr Bush and Mr Blair isolated figures, before their home audiences and on the global stage. In the United States, James Baker, long-term ally of the Bush clan, respected statesman and king-maker, has floated a number of unmentionables. They include a phased withdrawal from Iraq and direct talks with Syria and Iran. They add up to an admission that the war was a terrible mistake.

In a subsequent television interview - rare in itself - Mr Bush broke the taboo on comparisons between Iraq and Vietnam, vaguely agreeing that there might be parallels between the Tet offensive then and the upsurge in violence in Iraq now. It was not clear which particular aspect of the parallel Mr Bush was accepting: the pre-election timing, the moment at which possible defeat had to be faced, or something else. But the taboo was broken. The cost of Iraq to Mr Bush in congressional seats will be evident in a little more than two weeks.

Here in Britain, Mr Blair chose to side-step an open rift with the top brass by saying that he agreed with assessments made by the Chief of the General Staff, General Sir Richard Dannatt. Given that Gen Dannatt's comments included the observation that we had "effectively kicked the door in" in Iraq and the inference that foreign forces were doing more harm than good, full agreement seemed improbable.

The balance of authority, however, is now such that Mr Blair could not risk challenging the general, lest he reopen questions about his own culpability. Last night, British troops were on stand-by to return to Amara, a city they had handed over to Iraqi forces only months before. The day when Iraqis will be able to ensure the country's security alone - Mr Blair's benchmark for withdrawal - seems very far away.

Yet the one acknowledgement that has not been heard from either leader is the one that would make all the difference: a belated acceptance that the invasion of Iraq was a mistake. In her letter of resignation as a Labour MP, Clare Short cited the "half-truths and deceits" she said that Mr Blair had used to win support for the war in Iraq and the way she said the Labour chief whip had tried to silence her.

The cost of the misjudgements that took the US and Britain becomes clearer every day. Until Mr Bush and Mr Blair admit their errors, however, their responsibility will be the over-riding issue for the voters, not the free-ranging discussion that is also needed about how to get our forces, and Iraq, out of this catastrophic mess.