He provided the pretext that they needed to put their plans in motion. They came into office wanting to invade Iraq. They needed help building the case and Chalabi was more than happy to provide it.
He even later admitted to lying, but basically said the ends justified the means.
"In Baghdad, the Iraqi leader accused of feeding false prewar intelligence to Washington said his discredited information about Saddam Hussein's weapons had achieved the aim of convincing the US to topple the dictator.
Ahmad Chalabi and his London-based Iraqi National Congress for years provided a conduit for Iraqi defectors who were debriefed by US intelligence agents. Many US officials blame Mr Chalabi for providing false or wildly exaggerated intelligence about Iraq's weapons.
Mr Chalabi shrugged off charges that he had deliberately misled US intelligence. "We are heroes in error," he said. "As far as we're concerned we've been entirely successful. Our objective has been achieved. That tyrant Saddam is gone and the Americans are in Baghdad. What was said before is not important.
"The Bush Administration is looking for a scapegoat. We're ready to fall on our swords if he wants." Mr Chalabi's comments are likely to inflame the debate on both sides of the Atlantic over the quality of prewar intelligence, and the spin put on it by President George Bush and the British Prime Minister, Tony Blair."
http://www.smh.com.au/articles/2004/02/19/1077072781286.html