The latest comments by US Secretary of State Colin Powell on the existence, or otherwise, of Iraq's weapons of mass destruction mark another step back from the unyielding position the Bush administration held in the lead-up to the war.
By the BBC's Sebastian Usher
Then, the threat of Saddam Hussein's alleged chemical and biological capabilities was presented as so urgent, it had to be dealt with at once.
The search goes on for conventional arms and WMD
Now Mr Powell has said that it is actually an "open question" whether or not the Iraqis had stocks of weapons of mass destruction before the war.
Mr Powell's latest comments were in response to questions put to him by reporters accompanying him on a trip to Georgia.
They wanted his response to the statement on Friday by the outgoing head of the US weapons inspection team currently in Iraq, David Kay, that he did not believe there ever were any stockpiles.
Mr Powell said the answer was that no-one knew yet and it remained up to the weapons inspectors to continue their job in Iraq till they found the answer, one way or the other.
Such uncertainty is far from the stern, unblinking warning Mr Powell delivered to the United Nations Security Council just a little under a year ago, in his most dramatic call for the problem of Saddam Hussein's regime to be dealt with.
"Our conservative estimate is that Iraq today has a stockpile of between 100 and 500 tonnes of chemical weapons agent," he said then.
"That is enough agent to fill 16,000 battlefield rockets. Even the low end of 100 tonnes of agent would enable Saddam Hussein to cause mass casualties across more than 100 square miles of territory."
Now Mr Powell is playing down the importance of those figures, saying it was all about needing the answers to questions - how many tonnes of chemical weapons did the Iraqis possess, how many litres of anthrax?
The key point, Mr Powell now says, is that Iraq failed to provide an honest, comprehensive declaration of its capabilities, whatever they were.
However Mr Powell puts it, it is clear now that the Bush administration is increasingly distancing itself from the issue of weapons of mass destruction and trying to make it seem less significant, while the actual investigations on the ground in Iraq appear to be in the process of being steadily wound down.
This is bad news, obviously, for Mr Bush but unlikely to prove fatal for his re-election chances this November.
For British Prime Minister Tony Blair, on the other hand, the stakes could not be higher.
He put his most precious asset on the line over WMD - his trustworthiness.
With each revelation that the threat may have been exaggerated, his credibility suffers further.
Some evidence of weapons programmes was discovered
The comments by David Kay have put new pressure on him, with opposition politicians in Britain again calling for a public inquiry into the decision to go to war.
And Mr Blair's former Foreign Secretary Robin Cook has now said it is time for him to admit defeat on the issue and accept that there were no serious stocks of WMD in Iraq.
"It is becoming really rather undignified for the prime minister to continue to insist that he was right all along, when everybody can now see he was wrong, when even the head of the Iraq Survey Group has said he is wrong. The threat did not exist," said Mr Cook.
"I think it's very important Tony Blair does concede that there were mistakes made," he added. "If we don't face up to the fact that we got it wrong, then we're not going to learn the lesson."
For Mr Blair, these latest developments are the last thing he needs as he braces himself for the toughest test of his political career.
That is the publication of the Hutton inquiry on Wednesday into the suicide of a government weapons expert who may or may not have suggested that Downing Street consciously exaggerated the case for war.
It would be difficult to blame Mr Blair if he were feeling left a little high and dry by his American allies as he faces his moment of truth.