Democrats attack Gore's decision
Howard Dean shakes hands with Al Gore, who endorsed Dean as "the only major candidate who made the correct judgment about the Iraq war."
CNN's Dan Lothian on how the last scheduled debate between the '04 Dems was overshadowed by the Gore endorsement.
Al Gore endorses Howard Dean as the Democratic candidate for president.
Dean is named in a lawsuit seeking access to records from his years as Vermont's governor.
MANCHESTER, New Hampshire (CNN) -- Democratic presidential aspirants met in New Hampshire for the last debate of year, but the campaign was overshadowed by Al Gore's endorsement of former Vermont Gov. Howard Dean.
Sen. Joseph Lieberman lashed out at the former vice president Tuesday, saying he was surprised Gore would back a candidate who "will take this party back to where we were before [President] Bill Clinton."
Gore's endorsement substantially deepened Dean's fast-developing drive for dominance in the nine-candidate field of would-be challengers to President Bush.
The announcement could cement Dean's status as the leading Democratic candidate heading into the kickoff contests now just weeks away in Iowa and New Hampshire.
Lieberman, who was Gore's vice-presidential running mate in 2000, appeared to have the most to lose by Gore's endorsement of another candidate.
Lieberman said he spoke by phone with Gore for about four or five minutes Tuesday morning -- a phone call he said came "too late."
"I don't have anything to say today about Al Gore's sense of loyalty," said Lieberman, who had waited to announce his candidacy until after Gore said he would not run in 2004. "I have no regrets about the loyalty that I had to him."
But he said he was caught off-guard.
"I was surprised about the decision. I was surprised that Al Gore didn't notify me before I learned about it from the media -- that would have been the right thing to do. I was surprised that Al Gore would endorse a candidate who stands for so many things that Al Gore has not stood for."
Lieberman also said political endorsements "don't pick presidents," and he vowed to fight to give the nation "the fresh start it needs, so help me God."
He added that it's "less likely now" that Gore could play a key role in any future Lieberman administration.
According to a Democrat close to Gore, the former vice president had placed calls to Lieberman and his staff once word was leaked Monday that he planned to endorse Dean, but the calls were not returned.
The topic of the endorsement came up early in Tuesday evening's Democratic debate sponsored by ABC News and WMUR-TV. (Full story)
Sen. John Kerry of Massachusetts stood by Lieberman.
"I was sort of surprised today, actually, by the endorsement, because I thought that Joe Lieberman had shown such extraordinary loyalty in delaying his own campaign, that it surprised me," Kerry said to applause from the audience.
Prior to Tuesday's endorsement, a source told CNN that Gore -- the Democratic Party's presidential candidate in 2000 -- thinks a protracted primary campaign would serve only to help President Bush.
Erik Smith, a campaign press secretary for Rep. Dick Gephardt of Missouri, sounded as if the Gephardt team was surprised by the news.
Dean and Gephardt are the top two candidates in Iowa. (Gephardt calls for increased homeland security funding)
"Dick Gephardt fought side-by-side with Al Gore to pass the Clinton economic plan, pass the assault weapons ban and defend against Republican attacks on Medicare and affirmative action. On each of these issues, Howard Dean was on the wrong side," Smith said.
Paul Begala, a political adviser to President Clinton and now a host of CNN's "Crossfire," called the endorsement an "enormous boost" that would clearly give Dean momentum going into Iowa and New Hampshire.
"It's very good for him," Begala said. "I wouldn't go so far as to say it locks anything up, though, because people want to make up their own minds."
The New Hampshire primary is scheduled for January 27.
Dean pulling ahead
Howard Dean, in thanking Al Gore for his support: "We have needed a strong, steady hand in this party."
With the Dean campaign gaining momentum, a new CNN/USA Today/Gallup poll shows Dean widening his front-runner status among the eight other Democratic candidates.
The poll showed that 25 percent of registered Democrats surveyed support Dean as their nominee, with retired Gen. Wesley Clark coming in second with 17 percent. (Poll: Dean's New Hampshire lead increases)
In an interview before the news broke on CNN's "Judy Woodruff's Inside Politics," Dean played down his front-runner status.
"The pundits in Washington have been talking about me as the front-runner for a long time," Dean said.
"Well, guess what, the people of Iowa, New Hampshire, South Carolina and Arizona and so forth get to decide who the front-runner is. So, it's nice talk, but I'm not buying it."
CNN's John King and Kelly Wallace contributed to this report.