After a pair of primary victories in the South, front-runner John Kerry (search) is looking ahead to Wisconsin to shed the rest of his competition, which is hanging on by a thread, and move on to challenge President Bush.

Retired Army Gen. Wesley Clark (search) also formally dropped out of the race Wednesday.

"We decided we're going to end this phase of the journey even more full of hope and even more committed to the betterment of America," Clark said from Little Rock, Ark., in announcing his move.

"It was a tremendous honor and it was a call to duty … you proved to me a general can do great things when he has the greatest troops in the world. I can't tell you how honored and humbled I am by your spirit, your honor and your sacrifice … this has been every bit a cause as it has been a campaign."

He also heralded the other candidates for their hard work on the campaign trail, crediting them for bringing Democratic issues to the forefront of the American audience.

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"Our country is well served by John Kerry, John Edwards (search) and Howard Dean (search) and I applaud them," Clark said.

Kerry on Tuesday took first prize in the Virginia and Tennessee primaries, showing that a New Englander can win in Dixie.

Edwards, who wanted to prove his Southern roots would propel him to the top, came in second. Clark had a disappointing third-place showing in both states.

Kerry now has 507 delegates to Dean's 182, with Edwards at 163 and Clark at 96; 2,162 are needed to snare the nomination.

Kerry was resting at his Washington home before returning to the campaign trail Friday to stop in Wisconsin, which holds a primary next Tuesday, and Nevada, which holds caucuses on Saturday.

Dean, who's looking to a Wisconsin win to keep his campaign on life support, accused Kerry on Wednesday of being part of the "corrupt political culture in Washington."

Edwards' strategy, meanwhile, is to stifle a Dean comeback in Wisconsin, emerge as the obvious alternative and capitalize on being the sole Southerner left in the race.

"He's ahead and I'm the underdog," Edwards said of Kerry in an interview with The Associated Press Wednesday. "But I'm in the place that I wanted to be — one-on-one with somebody, in this case Senator Kerry."

And, anticipating a Bush v. Kerry race in November, the Bush campaign said they will portray the Massachusetts senator as a tax-raiser who wants to roll back efforts in Iraq and changed from a war supporter to an opponent when his position started to hurt him in the Democratic primary.

"Democrats are supporting his campaign, and we are anxious for the time when we'll have a chance to highlight the clear contrast that voters will have in this election between George Bush's positive leadership and the negativity and pessimism that's being offered by the Democratic candidate," said Bush spokesman Scott Stanzel.

Southern Factor Didn't Work

Asked whey southerners Edwards and Clark couldn't score a first-place victory, Republican Sen. Lamar Alexander of Tennessee said, "What really happened is people voted for a winner … Tennesseans, like everybody else, voted for Kerry because he came out of New Hampshire and Iowa well."

Sen. George Allen, R-Va., said that Tuesday's Virginia voters were smaller in number and more liberal than in past elections.

"If you look at the voter turnout in Virginia … it's one half of what it was four years ago when George W. Bush as governor was running against [Arizona Sen.] John McCain.

"The bottom line is, though, that in Virginia and also, I think I can speak for Tennessee, the vast majority of taxpayers and veterans are strong supporters of George Bush."

The Alliance for Economic Justice (search) — an umbrella group of 21 international labor unions, including the Teamsters, United Auto Workers and United Steelworkers of America — unanimously voted to support Kerry. The alliance, which had previously endorsed Missouri Rep. Dick Gephardt, will officially announce their support on the eve of the Wisconsin primary.

Two of New York's most prominent black politicians, Rep. Charles Rangel and former state Comptroller H. Carl McCall, also endorsed Kerry.

A Mountain 'Too Steep to Climb'

Sources told Fox News that Clark lacked the cash to advertise aggressively in Wisconsin, and senior staffers said they simply couldn't afford to travel the country without pay for a candidate who has little hope of winning the nomination.

"The decision was made on a number of factors, not just the order of finish," Clark adviser Matt Bennett said Wednesday of Clark's decision to drop out. "He saw the numbers and thought about it a bit … the mountain got too steep to climb."

Edwards said he wouldn't drop out, and not one Democratic official has asked him to.

"I'm going to be the nominee," Edwards told The Associated Press. "I'm definitely staying in."

The Edwards campaign hopes that after Wisconsin, voters will take a second look at Kerry and turn to Edwards, then the only viable option. Campaign manager Nick Baldick argues that with two weeks between Wisconsin and March 2, Edwards will have plenty of time to make his case and voters will have a chance to compare instead of simply going with "who's doing well, who's on a roll."

Chinese Firedrill of Support

The Kerry and Edwards campaigns were frantically calling Clark supporters, organizers and donors.

Sources close to the Edwards campaign said he believes that Clark's support is not inherently going to move to Kerry. The North Carolina senator plans to court Clark supporters openly on the campaign trail.

"I think there will be some folks that support Wes supporting us," Dean told his own supporters in Milwaukee, Wis. "We have a fair amount of similarity in our outsider status in this race, and I'm sorry to see him leave the race."

Edwards' team and polls suggest that the candidate knows he will lose Wisconsin, but is looking for a strong second-place showing, within a 5- to 7-point range, so he can keep fighting. A blowout 15-25 point margin would end the race for Edwards, sources said.

Meanwhile, in Milwaukee, Dean thanked the local American Federation of Teachers (search) for their endorsement, calling it "courageous" in light of the fact that the national AFT endorsed Kerry. He said he would support the Democratic candidate chosen to go head-to-head with Bush in November, even if it's Kerry, whom he called the "lesser of two evils."

But Kerry "is clearly not the best person to carry the banner of the Democrats in this race, because he's behaved so much like a Republican, both in his voting record and in his political practices and fundraising," Dean said.

"It's just what we don't need heading the Democratic Party."

Dean also railed against groups throwing money at ads he says demean him.

Labor unions and former Democratic New Jersey Sen. Bob Torricelli were among big givers to a group that spent over $626,000 on anti-Dean ads in December.

Torricelli was investigated and cleared by the Justice Department for giving gifts to a former donor who pleaded guilty to fund-raising abuses. Torricelli now raises money for Kerry.

"What we now see is that John Kerry is part of the corrupt political culture in Washington," Dean said. "That's exactly what I'm asking Wisconsin voters to stand up against."

Fox News' Carl Cameron and The Associated Press contributed to this report.