MoveOn.org and the national coalition Win Without War on Tuesday unveiled their campaign demanding Congress should pass a motion reprimanding the president.
They say Bush should be admonished for "deliberately misrepresenting the truth about intelligence concerning weapons of mass destruction in Iraq and links between al-Qaida and the government of Saddam Hussein".
"Bush waged a campaign of deceit," said Professor Mel Goodman, a senior fellow at the Center for International Policy in Washington DC and a former CIA official who is promoting the campaign.
The two organisations say they have already collected more than 450,000 signatures on an email-based petition in just the past week, and will now use print and television advertising to boost their campaign.
"Bush waged a campaign of deceit"
Professor Mel Goodman,
former CIA official and senior fellow at the Center for
Bush announced last week an inquiry into intelligence about Iraqi weapons, due to report four months after the presidential election in November.
But critics insist the president himself is to blame for manipulating information about Iraq to build public support for a war the White House was determined to prosecute.
The move comes just two days after Bush admitted in a rare television interview that the intelligence he used to justify launching war on Iraq was wrong – but that he had acted in good faith.
The president told the NBC network on Sunday his claim on 17 March 2003 that intelligence had left "no doubt" Iraq possessed "some of the most lethal weapons ever devised" was incorrect.
Bush (R) admitted on Sunday that
claims about Iraq were flawed
But he denied he had attacked Iraq under false pretences. "I based my decision on the best intelligence possible," he said.
But Goodman, due to speak at the national press club in Washington for the launch of the censure campaign, told Aljazeera.net both the CIA and the Bush administration were guilty of "politicising intelligence in order to build the case for war".
MoveOn.org is a nationwide network of more than 1,700,000 online activists for popular democracy, while Win Without War represents 42 bodies who believe US security interests are best served through promoting international cooperation and law.
A Congressional censure of the president is an ill-defined punishment of uncertain constitutional status. But it is generally understood to be a resolution passed by both chambers of Congress that publicly rebukes the president.
On the only occasion a US president has been censured, a Whig-dominated Senate admonished Democrat President Andrew Jackson in 1843 in retaliation for his withholding documents.
Three years later, a Democrat-controlled Senate revoked the censure.