"Senator Kerry, I want to tell you how much I admire your service with the United States Navy and Vietnam," said Clark, a retired Army general. "As we say in the Navy, 'Sir, request permission to come aboard. The Army's here.'"
Kerry told the crowd that Clark would stand beside him and "help walk the point in this great battle as we go forward to take back the presidency of the United States. This is the first time in my life I've ever had the privilege of saying welcome aboard to a four-star general."
In another big get for the Democratic hopeful, the AFL-CIO (search) will also endorse Kerry for president next Thursday, Democratic sources confirmed to Fox News. That labor organization didn't even throw its backing behind Missouri Rep. Dick Gephardt before he dropped out of the presidential race.
Wisconsin holds its primary on Tuesday; there are 72 pledged delegates at stake there and polls make Kerry the favorite. Kerry already has 539 delegates, compared to 182 for Howard Dean (search) and 166 for John Edwards (search). It takes 2,161 delegates to clinch the nomination for president.
An American Research Group poll released Friday shows Kerry at the top with 53 percent of the vote in Wisconsin. Edwards is in a distant second place with 16 percent and Dean has 11 percent. Kerry's support increased from 41 percent in a survey taken last weekend to 53 percent after Clark's withdrawal.
Kerry, meanwhile, says he is prepared for an onslaught of criticism from the Republican Party and is ready to put on the gloves and fight against the barrage of expected dirty tricks.
"We've seen evidence. We know exactly where these guys are going to go, and I'm ready for it," Kerry said on the Don Imus (search) radio show Friday morning. "I've been through some tough races. I've been pretty well, you know, vetted and examined from one side to the other."
Getting Down and Dirty
Political observers and even national party officials say the showdown in November will be one of the nastiest yet.
In Nevada, which holds caucuses Saturday, GOP Chairman Ed Gillespie told Republicans Thursday night that Democrats were preparing to run "the dirtiest campaign in modern presidential politics."
"This is because they don't want a debate on the issues, and they don't want to run on Senator Kerry's record," Gillespie said. "I guess I can't blame them for that."
Kerry has rocketed toward the nomination in record setting time, benefiting from an escalated primary calendar that leaves voters little time to scrutinize his record. Polls show few Americans know much about him, meaning the Republican opposition might be able to easily define Kerry negatively.
Bush's re-election campaign launched its first attack ad against Kerry.
Posted on its official Web site and being e-mailed to Bush supporters are videos taking slaps at Kerry. One posted Thursday night mocks the front-runner's frequent claim that he intends to show the special interests the door if elected.
"Sounds good," says the announcer, while computer search results turn up newspaper stories that say Kerry has raised "more special interest money than any other senator," and that "nominations and donations coincided."
"Kerry ... brought to you by the special interests," says the announcer. "Millions from executives from HMOs, telecoms, drug companies, Ka-ching. Unprincipled?"
In response, Kerry's campaign issued a statement calling the ad "another attempt to avoid an honest discussion of the issues" and "unprincipled."
"We haven't been able to trust what George Bush has told us about the war or about the economy — we certainly can't trust what he has to say about the special interests," Kerry said. "George Bush has no more credibility on taking on the special interests than he does on creating jobs."
Dean has pummeled Kerry for accepting special interest money, which Kerry now criticizes. Edwards cast Kerry as a hopelessly lost Washington insider and until this week, Clark blasted Kerry as a flip-flopper. Now, Clark's singing a different tune.
"John, I'll work with you to do everything I can to take the White House back for its rightful owners, the American people," Clark told Kerry in announcing his endorsement. "President Bush hasn't led the American people, he's misled America time and time again and we have to put a stop to it."
But experts have mixed forecasts as to how much Clark's endorsement will help Kerry.
"Well, that almost clinches it for John Kerry ... the Wisconsin primary will probably wrap it up for John Kerry," said Rep. John Spratt, D-S.C. "It shows that John Kerry ... can win in the South, he can win in the Midwest, he can win in states like Wisconsin — I think that's going to give him an unstoppable momentum."
Republicans aren't sure the Clark backing will help Kerry much in Bush territory come November.
"I don't see any Kerry momentum — at the end of the day, Kerry's still going to be seen as a liberal from Massachusetts," said Rep. Jack Kingston, R-Ga. "He's not going to fare well in the South."
"I think it's going to be a nonstory by 6 p.m. tonight," he added.
Candidates on the Road
Kerry told Fox News that he's well rested after taking two days off and spending a lot of time working the phones.
He and his wife, Teresa Heinz Kerry, exchanged Valentine's Day presents Thursday night since they won't be together on Saturday.
Edwards, a North Carolina senator, continued to hammer home his jobs message Friday as he met with steel workers in Milwaukee, Wis., who recently found out their company is moving 400-500 jobs to Mexico.
The No. 2 candidate said Friday that Democratic voters "still have a choice" because the race is far from settled.
"First of all, the nomination process is going to go on for a while, well into March," Edwards said.
But he conceded he is facing a front-loaded primary season designed to yield a nominee quickly, which makes slowing a front-runner difficult.
"I think you fight against the calendar," Edwards said. "As long as I can get out and get this message out ... every place it's gotten out, it's worked."
Edwards' team is looking for a strong second-place showing in Wisconsin to remain viable. A blowout 15-25 point margin would end the race for Edwards, sources said. Edwards was scheduled to travel to Los Angeles later Friday for fund raising.
Dean visited a dairy farm in Wisconsin, where he said farmers should be guaranteed a set price for their milk, even if it costs consumers "a few pennies more for a gallon of milk."
Win a Date With a Hollywood Starlet
Meanwhile, former Vermont Gov. Dean and Edwards continue to woo Clark supporters.
"We can change this country, but we are losing the opportunity to do that as the election gets closer," Dean told supporters in Madison, Wis., on Thursday. "There are some good candidates in this race. There are people here who support Wes Clark. I ask for your help, because Wes Clark and I have one thing in common: We are both not from Washington, D.C."
Dean held a forum on economic issues Friday at a community college in Cleveland, Wis., and then headed south to Milwaukee, stopping first at the Wonderful World coffee shop in Sheboygan.
Shop owner and folk singer Judy Stock treated him to an impromptu song in Swahili, which she also sang in English. "Every burden shall be rolled away," she sang.
When asked whether he thought the lyrics were appropriate, Dean replied: "Very appropriate."
Edwards said Clark's withdrawal from the race could help his own candidacy because they tend to attract the same type of Democratic and independent voters.
For a little bit of comic relief, on NBC's "Tonight Show with Jay Leno" Thursday, Ohio Rep. Dennis Kucinich (search) took his quest for a girlfriend to late-night television — and won a date with actress Jennifer Tilly.
The congressman, who has been divorced twice, asked questions of a trio of unseen women Thursday in a takeoff on "The Dating Game." Responses by Tilly, actress Cybill Shepherd and Los Angeles radio talk show host Kim Serafin blended sexual innuendo with politics and references to Kucinich's environmental concerns.
Fox News' Carl Cameron, Major Garrett, Molly Henneberg, Catherine Loper and The Associated Press contributed to this report.