Once wary of having Howard Dean become their party’s presidential nominee, some leading Congressional Democrats appear to be warming to the idea that the former Vermont governor might be the voters’ choice to challenge President Bush in 2004.

Over the past few months, Dean has sprinted from long shot to frontrunner, based largely on his fundraising prowess and ability to rally a sleeping base still stunned by the 2000 elections in which Democrats lost control of both the White House and the Senate.

“I think his campaign has been very impressive and his energy level is high and obviously he is connecting with voters,” said Sen. Mary Landrieu (D-La.), who has yet not yet endorsed a candidate.

“I think that a lot of people took his candidacy for granted, thinking he was a one-trick pony with one issue,” said a Democratic Congressional campaign operative, referring to Dean’s opposition to war in Iraq. “But it has turned out he has surprised an awful lot of people.”

So far, Dean has received the backing of only eight Democratic Members, trailing Rep. Richard Gephardt (D-Mo.) by 23 endorsements but leading Sen. Bob Graham (D-Fla.) by one in the presidential endorsement sweepstakes. With four Senators also seeking the Democratic nomination, Delaware Sen. Tom Carper, who is backing Sen. Joe Lieberman (Conn.), is the only Member of the chamber to endorse someone other than a home-state colleague.

But primaries are not won and lost by Members’ pledges of support, and Dean appears to be convincing much of the hungry Democratic base that he is the person capable of defeating Bush next year.

He has done this by employing a combination of new and old campaign tactics. The former governor has effectively used the Internet to help seed his campaign war chest, but he reaches out to voters by holding old-fashioned campaign rallies where he offers a blend of sharp criticism of Bush and his legislative vision.

Over four days last month, Dean held rallies in nine cities drawing a combined 43,750 people, according to attendance estimates posted on his Web site.

After witnessing one such event in Portland, Sen. Ron Wyden (D-Ore.) marveled at Dean’s ability to draw 5,000 people to the Aug. 24 rally.

“In Oregon he put together a tremendous grassroots effort,” Wyden said. “He had a rally with 5,000 people on a summer Sunday.”

“The passion thing is really resonating,” said Sen. Jay Rockefeller (D-W.Va.). “And the fact that he was a governor means a lot, I think.

“But even that in and of itself does not get him the nomination,” cautioned Rockefeller, who noted the Democratic primary field is still taking shape. “What if [retired Gen.] Wesley Clark gets into the race?”

But the bigger challenge for Dean will be defeating Bush in a general election contest, several Congressional aides and campaign operatives noted. His anti-war stance is unlikely to have the same appeal to swing voters as it has had with the liberal base, whose support is needed to advance beyond the primary.

“I think there are a lot of people who are concerned about his anti-war stand,” said a senior Senate Democratic aide.

And the approval of the civil union bill when he was the governor of Vermont could hurt Dean in the socially conservative South, some Capitol Hill insiders suggested.

“That is his Achilles’ heel in the South and it will not be well-received,” a chief of staff for a conservative House Democrat said of Vermont’s civil union bill.

“There are certainly some questions there that he is going to have to answer,” added Sen. Blanche Lincoln (D-Ark.). “We will wait and see how he answers them.”

“Clearly he has some things that make him less than the most attractive candidate at this point in my part of the country,” added Sen. John Breaux (D-La.). “But it is a long way to Election Day.”

But Sen. Fritz Hollings (D-S.C.) predicted the South would not reject Dean based upon his criticism of the war and his support of civil unions.

“I am not going to comment on it other than in the general sense, he will do well in the South,” said Hollings. “He balances budgets. He is against all of these tax cuts, and he knows how to be fiscally responsible.”

Still, Sen. Evan Bayh (D-Ind.) said Democrats need to be careful not to cede national security and value issues to the Republican Party and suggested that for Dean to be successful in the general election he needs to move to the center in order to appeal to swing voters.

“Every candidate has strengths and weaknesses, and I don’t think it is too late for Governor Dean to adopt the kind of moderate tone and agenda that would appeal to swing voters even if he has energized the Democratic Party base,” said Bayh, who serves as chairman of the Democratic Leadership Council, a group that has sparred with Dean in the past. “The longer that he has to remain on the left, the harder it will be to accomplish both of those objectives.”

While some Democrats are privately expressing fear that having Dean at the top of the ticket could hurt Senate Democrats’ chances in states such as Georgia, North Carolina, South Carolina and South Dakota next year, Senate Minority Leader Tom Daschle (D-S.D.) said he harbors no similar concerns.

“I am not worried about that,” Daschle said. “I think anybody that can win the nomination as a Democrat is electable as a candidate.

“I think time will tell whether it is Mr. Dean or anybody else,” Daschle added.