It is interesting to look at how the Bush Administration has backpedalled in their WMD rhetoric after no WMDs were found following the Iraq war. This timeline of quotes is taken largely from this page.

See also this or this selection or this great article summarizing Fox News' lies and contradictions regarding the Iraq war and the WMD hunt.
August 26, 2002, Dick Cheney
Simply stated, there is no doubt that Saddam Hussein now has weapons of mass destruction. [Speech to VFW National Convention]

December 6, 2002, White House spokesman Ari Fleischer
The president of the United States and the secretary of defense would not assert as plainly and bluntly as they have that Iraq has weapons of mass destruction if it was not true, and if they did not have a solid basis for saying it. [BBC article]

September 12, 2002, George W. Bush
Right now, Iraq is expanding and improving facilities that were used for the production of biological weapons. [Speech to UN General Assembly]

September 24, 2002, Tony Blair
The assessed intelligence has established beyond doubt that Saddam has continued to produce chemical and biological weapons, that he continues in his efforts to develop nuclear weapons, and that he has been able to extend the range of his ballistic missile programme. [Comments on September Dossier]

January 9, 2003, Ari Fleischer
We know for a fact that there are weapons there. [Press Briefing]

January 28, 2003, George W. Bush
Our intelligence officials estimate that Saddam Hussein had the materials to produce as much as 500 tons of sarin, mustard and VX nerve agent. [State of the Union Address]

February 5, 2003, Colin Powell
We know that Saddam Hussein is determined to keep his weapons of mass destruction, is determined to make more. [Remarks to UN Security Council]

February 8, 2003, George W. Bush
We have sources that tell us that Saddam Hussein recently authorized Iraqi field commanders to use chemical weapons # the very weapons the dictator tells us he does not have. [Radio Address]

February 28, 2003, Colin Powell
If Iraq had disarmed itself, gotten rid of its weapons of mass destruction over the past 12 years, or over the last several months since (UN Resolution) 1441 was enacted, we would not be facing the crisis that we now have before us . . . But the suggestion that we are doing this because we want to go to every country in the Middle East and rearrange all of its pieces is not correct. [Interview with Radio France International]

March 7, 2003, Colin Powell
So has the strategic decision been made to disarm Iraq of its weapons of mass destruction by the leadership in Baghdad? . . . I think our judgment has to be clearly not. [Remarks to UN Security Council]

March 16, 2003, Dick Cheney
We know he [Saddam] has been absolutely devoted to trying to acquire nuclear weapons. And we believe he has, in fact, reconstituted nuclear weapons. [Interview on NBC's 'Meet the Press'; Article]

March 17, 2003, George W. Bush
Intelligence gathered by this and other governments leaves no doubt that the Iraq regime continues to possess and conceal some of the most lethal weapons ever devised. [Address to the Nation]

March 21, 2003, Ari Fleisher
Well, there is no question that we have evidence and information that Iraq has weapons of mass destruction, biological and chemical particularly . . . all this will be made clear in the course of the operation, for whatever duration it takes. [Press Briefing]

March 22, 2003, Gen. Tommy Franks
There is no doubt that the regime of Saddam Hussein possesses weapons of mass destruction. And . . . as this operation continues, those weapons will be identified, found, along with the people who have produced them and who guard them. [Press Conference]

March 23, 2003, Defense Policy Board member Kenneth Adelman
I have no doubt we're going to find big stores of weapons of mass destruction. [Washington Post]

March 22, 2003, Pentagon Spokeswoman Victoria Clark
One of our top objectives is to find and destroy the WMD. There are a number of sites. [Press Briefing]

March 30, 2003, Donald Rumsfeld
We know where they are. They're in the area around Tikrit and Baghdad and east, west, south and north somewhat. [ABC Interview; Article]

April 9, 2003, Neocon scholar Robert Kagan
Obviously the administration intends to publicize all the weapons of mass destruction U.S. forces find # and there will be plenty. [Washington Post op-ed]

April 10, 2003, Ari Fleischer
But make no mistake # as I said earlier # we have high confidence that they have weapons of mass destruction. That is what this war was about and it is about. And we have high confidence it will be found. [Press Briefing]

April 24, 2003, George W. Bush
We are learning more as we interrogate or have discussions with Iraqi scientists and people within the Iraqi structure, that perhaps he destroyed some, perhaps he dispersed some. And so we will find them. [NBC Interview]

April 25, 2003, Donald Rumsfeld
There are people who in large measure have information that we need . . . so that we can track down the weapons of mass destruction in that country. [Press Briefing]

May 3, 2003, George W. Bush
We'll find them. It'll be a matter of time to do so. [Remarks to Reporters]

May 4, 2003, Colin Powell
I'm absolutely sure that there are weapons of mass destruction there and the evidence will be forthcoming. We're just getting it just now. [Remarks to Reporters]

May 4, 2003, Donald Rumsfeld
We never believed that we'd just tumble over weapons of mass destruction in that country. [Fox News Interview]

May 6, 2003, George W. Bush
I'm not surprised if we begin to uncover the weapons program of Saddam Hussein # because he had a weapons program. [Remarks to Reporters]

May 12, 2003, Condoleeza Rice
U.S. officials never expected that "we were going to open garages and find" weapons of mass destruction. [Reuters Interview]

May 13, 2003, Maj. Gen. David Petraeus, Commander 101st Airborne
I just don't know whether it was all destroyed years ago # I mean, there's no question that there were chemical weapons years ago # whether they were destroyed right before the war, (or) whether they're still hidden. [Press Briefing]

May 26, 2003, Gen. Richard Myers, Chairman Joint Chiefs of Staff
Given time, given the number of prisoners now that we're interrogating, I'm confident that we're going to find weapons of mass destruction. [NBC Today Show interview]

May 27, 2003, Donald Rumsfeld
They may have had time to destroy them, and I don't know the answer. [Remarks to the Council on Foreign Relations]

May 28, 2003, Paul Wolfowitz
For bureaucratic reasons, we settled on one issue, weapons of mass destruction (as justification for invading Iraq) because it was the one reason everyone could agree on. [Vanity Fair interview]

June 8, 2003, Condoleezza Rice
No one ever said that we knew precisely where all of these agents were, where they were stored. [NBC's 'Meet the Press'; Article; Article]