California, long a major cash source for candidates of both parties, is poised to become more influential in the electoral process as well, having moved its primary to next Feb. 5. As a result, the state Democratic weekend convention was expected to attract all the party's major presidential contenders except Delaware Sen. Joe Biden, who was campaigning in South Carolina.
Saturday's program featured appearances by front-runners Clinton and Obama, as well as Connecticut Sen. Chris Dodd and Ohio Rep. Dennis Kucinich.
Clinton unleashed an unusually personal critique of Bush, accusing his administration of ignoring scientific evidence about global warming and stem cell research and lying about the effects of toxic dust at the World Trade Center site.
Her voice hoarse from days of campaigning, Clinton brought the 2,000 delegates to their feet when she said she wished she could turn the clock back to a different time.
"Somebody said to me that he wished we could just rewind the 21st century and just eliminate the Bush-Cheney administration, with all their mistakes and misjudgments," she said to cheers. "People are ready for leaders who understand it is our votes who put them in power, our tax dollars that pay the bills."
Obama, who has made his early opposition to the Iraq conflict a central theme of his campaign, told delegates he was proud to have bucked popular opinion at the time. It was a subtle but direct jab at Clinton, who voted in 2002 to give Bush authority to invade Iraq.
He renewed his call for the political parties to find common ground and declared it was time to "turn the page" on issues like health care, education and energy independence.
But he, like Clinton, also leveled a sharp critique of Bush, saying "the president may occupy the White House, but for the last six years the position of leader of the free world has remained open." And he characterized the administration's foreign policy as "bluster and bombast."
Obama and Clinton both called on Bush to sign legislation passed by Congress last week tying funding of the war to a timeline for removing troops. Bush has indicated he will veto the bill.
Both Obama and Clinton were received warmly by the left-leaning, activist crowd - a stark contrast to the same convention four years ago, when the party was bitterly divided over the Iraq war.
There, former Vermont Gov. Howard Dean - then a little-known figure in the 2004 Democratic field - thrilled delegates with his fiery denunciation of the conflict. His rivals at the time, including Massachusetts Sen. John Kerry, who eventually won the nomination, were loudly booed for defending their 2002 vote to authorize the war.
Clinton cast the same vote in 2002, but met with only sporadic heckling during her speech.
The New York senator also promised to "treat all Americans with dignity and equality no matter who you are and who you love." The pledge was a clear bow to California's politically active and influential gay community.
She lambasted the speech nearly four years ago, in which Bush - under a "Mission Accomplished" banner on an aircraft carrier returning to home port - declared an end to major military actions in Iraq.
That speech, Clinton said, was "one of the most shameful episodes in American history. ... The only mission he accomplished was the re-election of Republicans."
Dodd echoed the day's anti-war sentiment in his remarks.
"My friends, this is not about cutting and running," he said, accusing the White House of trying to police a civil war.
Earlier Saturday, candidates who attended South Carolina's party convention said they thought the United States has lost its global standing during Bush's presidency. America, they said, needs a Democratic commander in chief to restore its place in the world. "We are today internationally and domestically a nation that is no longer a leader," New Mexico Gov. Bill Richardson said. Former Sen. John Edwards, the 2004 vice presidential nominee, said the world needs to see that "America can be a force for good." "What their perception is that America is a bully and we only care about our short-term interests," Edwards said. "The starting place is to end the bleeding sore that is the war in Iraq." Richardson, Edwards and Biden said they would make ending the war a priority. "The American people are looking for us as Democrats," said Biden, chairman of the Senate Foreign Relations Committee. "They're looking for someone literally, not figuratively, to restore America's place in the world."