Former Vermont Gov. Howard Dean’s campaign for the Democratic presidential nomination received the endorsement of Rep. Bennie Thompson (Miss.) Tuesday, giving the one-time outsider candidate a one-person lead over former House Minority Leader Richard Gephardt (Mo.) in the competition for Capitol Hill backers.

Dean now has 35 Congressional supporters, — one more than Gephardt, 12 more than Sen. John Kerry (Mass.) and 18 more than retired Gen. Wesley Clark. Even Gephardt aides admit Dean has momentum heading toward next week’s Iowa caucuses. The former governor picked up Rep. Corrine Brown’s (Fla.) endorsement Monday.

Gephardt and Dean are currently engaged in a tight contest in Iowa, where the latest independent polling showed Dean holding a single-digit lead over Gephardt.

Many observers have speculated that if Gephardt does not win in Iowa he will not continue in the race to New Hampshire’s Jan. 27 primary. For his part, the Missouri Congressman has continued to maintain that he will win the Hawkeye State.

Little known in Washington at the start of 2003, Dean had only nine endorsers as late as October.

But as he ascended to the top of the field in the early primary states and his fundraising grew beyond even the campaign’s most optimistic goals, Members have quickly jumped on the bandwagon, including Iowa Sen. Tom Harkin.

Gephardt, on the other hand, announced 30 House endorsements in May 2003 and has added only four to the list since that time.

One senior Democrat not affiliated with any of the presidential campaigns said that the recent spate of Dean endorsements is based on the fact that “Members like to be with a winner” and that “the Caucus is very liberal.”

For many Members, Dean’s opposition to the war in Iraq is the key to their support of the governor, the source said.

One Dean backer, Rep. Zoe Lofgren (D-Calif.), said she is so confident of her candidate’s chances that she has already spoken to Members currently supporting Gephardt in hopes of winning their endorsements if and when he drops out of the race.

“A lot of people who have endorsed Dick have told me that if Dick does not win they think Dean is great,” Lofgren said.

Gephardt senior adviser Steve Elmendorf shot back: “Our focus right now is on beating Howard Dean in Iowa and when we do we will welcome the Dean supporters to join our campaign.”

Despite taking some hits on racial issues, Dean continues to pull in minority endorsements. Thompson is the eighth member of the Congressional Black Caucus to endorse Dean including the organization’s chairman, Rep. Elijah Cummings (Md.), and vice chairwoman, Rep. Sheila Jackson Lee (Texas).

Dean came under attack from the Rev. Al Sharpton in a debate Sunday night for his lack of blacks and Hispanics in his Cabinet during his 10 years as Vermont’s governor.

Earlier in the campaign he came under fire for saying he wanted to be a candidate for “guys with Confederate flags in their pickup trucks.” Sen. John Edwards (N.C) has also criticized Dean for his assertion that he is the only candidate who talks about race to white audiences.

One senior Democratic strategist expressed little surprise that the self-labeled “outsider” candidate would soon become the first choice of House Members.

“He stopped being the outsider candidate when he got the endorsement of [former Vice President] Al Gore and [former New Jersey Sen.] Bill Bradley,” the source said.