Rep. Richard Gephardt, challenged on his backing for a resolution authorizing war in Iraq (search), called Sunday for a "full, complete, bipartisan" investigation of the circumstances surrounding Congress' decision to authorize the war.

"We've got to make sure we get all the facts out," said the Democratic presidential candidate from Missouri.

Gephardt said he's troubled by some of the arguments President Bush used to make his case for war, including a claim in last year's State of the Union (search) speech that former Iraqi leader Saddam Hussein sought nuclear materials from Africa.

"I want a full, complete bipartisan inquiry into this to find out all the facts," he said.

Acknowledging his vote for the resolution authorizing force, Gephardt said he urged Bush to work with the United Nations-led inspection program looking for weapons of mass destruction.

He said he now wants to know whether Bush misled Congress and the country, or if Bush himself was misled by faulty intelligence.

Since the war, no such weapons have been found and questions have been raised about Bush's arguments for war. Intelligence officials have conceded they should have deleted the nuclear claim from Bush's speech because U.S. intelligence sources could not verify it.

Gephardt was questioned about the issue when he appeared at the latest "Hear it from the Heartland" forum, sponsored by Sen. Tom Harkin (search), D-Iowa.

While the head of the CIA (search) has taken responsibility for the nuclear claim, Gephardt argued that the president is ultimately responsible.

"There used to be a sign on the president's desk that said 'the buck stops here,'" said Gephardt. "That sign ought to be back there."

Gephardt argued that Bush has been ineffective in his effort to combat terrorism and is "not leveling with us about what needs to be done."