WASHINGTON – Jilted by former Vice President Al Gore, Howard Dean’s eight Democratic rivals forged ahead with their campaigns, taking heart in the fact that not a single vote has been cast.

Dean is already the front-runner in the Democratic primary, and Gore’s endorsement Tuesday only reinforces the strategy being pursued by each of his rivals – become the alternative to Dean’s anti-Iraq war, antiestablishment campaign.

“I don’t think that this endorsement makes Howard Dean any more electable than he was yesterday,” said Erik Smith, spokesman for Dick Gephardt, who is in a tight race with Dean in the Jan. 19 Iowa caucuses.

In politics, a month can change everything. A poll taken in December 1987 showed Gephardt, the Missouri congressman, at 6 percent among Iowa voters, but he went on to win the state’s caucuses.

The hope among Dean’s rivals is that he’s peaking too soon. Polls show him leading in New Hampshire by hefty double digits. If another candidate is able to narrow the lead and finish strong, they could call themselves the “comeback kid” and use the momentum in later states, as Bill Clinton did in 1992.

The opportunity exists beyond New Hampshire and Iowa. Seven states, including South Carolina and Missouri, hold their contests Feb. 3, and the race is unclear in that stage, with Dean rivals leading the polls in some of those states.

The Clintons, for their part, say they won’t endorse in the primary. Sen. Hillary Rodham Clinton, R-N.Y., said she considers it “more important to coalesce around a nominee” picked by the Democratic Party than a front-runner during the primary.

“I remember back in December of 1991, when my husband was, I don’t think, above 4 percent in the polls,” she told reporters in New York. “I remember all the way through the months of the primaries and the caucuses there was a hard-fought battle.”

Sen. Joe Lieberman, who didn’t even get a courtesy call before learning that his former running mate was endorsing Dean, said calls from supporters poured into his campaign Tuesday and he raised more money than in any other day this quarter.

“Here’s the emotion I feel: Determination,” he told reporters in Durham, N.H., before the Democratic presidential debate Tuesday night.

Dean, speaking from Cedar Rapids, Iowa, after appearing with Gore, said the endorsement doesn’t solidify anything. Dean said even though he’s grateful for Gore’s support, voters have yet to make the ultimate choice.

Donnie Fowler, who ran Gore’s field operations in 2000 and briefly served as Wesley Clark’s campaign manager, said the other candidates’ problem is not Gore’s endorsement, but Dean’s success in connecting with voters.

“They have to keep focused and continue to do what they originally planned to do, but the problem is that most of these guys’ original strategies haven’t worked as well as Dean’s,” he said. “I think that’s because they don’t understand the new tools of politics and they don’t understand people outside of Washington, D.C.”

Gore cited Dean’s ability to inspire voters and said Dean was the only candidate to take the right position on Iraq. Gore’s position is a blow to the candidates who worked and supported the congressional resolution on Iraq.

“This helps position Dean as much more in the mainstream because it will help people realize that Gore was anti-war as well,” said longtime Gore adviser Elaine Kamarck. “There is a pro-defense wing of the party that was anti-war.”

Sen. Edward M. Kennedy, D-Mass., who unsuccessfully sought the Democratic nomination in 1980, played down the significance of the Gore endorsement and said his support is still firmly behind John Kerry.

Kennedy said voters now are thinking about the holidays – not about making decisions on the future president. He said a lot is made of staff shake-ups and endorsements, but “ultimately it’s going to come down to the candidates.”

“I think people like to make up their own mind in the Democratic Party,” he said.