Former vice president Walter F. Mondale officially entered the race for Senate today, launching one of the most unusual -- and shortest -- campaigns of great political consequence in U.S. history.

Eighteen years after winning only his home state of Minnesota and the District of Columbia as the Democratic presidential nominee, Mondale entered a campaign rocked by tragedy and controversy, this time as a stand-in for his friend, the late Democratic Sen. Paul D. Wellstone.

At the historic State Theatre here, "Fritz" was given a rock star's welcome tonight from the party faithful who unanimously nominated him to replace Wellstone on the Nov. 5 ballot. Mixing new and old, the elder statesman, followed by throngs of Generation X Wellstone volunteers, entered the emotional meeting to the muscular, optimistic beat of U2's "Beautiful Day."

With Wellstone banners hanging over each shoulder, Mondale sounded every bit as populist and liberal -- though not nearly as fiery -- as his friend who died in a plane crash only five days earlier. "I will be your voice, and I will be Paul Wellstone's voice for decency and better lives," Mondale, 74, told the audience.

Wellstone died in a plane crash Friday, sending a state known for its political quirkiness into tear-filled tumult in the waning days of a high-stakes election. Republicans have hoped Minnesota might provide the one extra seat they need to reclaim the Senate majority they lost last year.

Polls had shown the race essentially neck-and-neck between Wellstone and GOP nominee Norm Coleman, a former St. Paul mayor. Coleman's campaign now must quickly retool to confront a new opponent in a suddenly somber atmosphere, and Republicans wonder if their chance will slip away.

Mondale, who spent 12 years in the Senate before becoming Jimmy Carter's vice president in 1976, enters the race as a favorite, according to a poll of likely voters taken Monday by the Minneapolis Star Tribune. The poll found Mondale leading Coleman, 47 percent to 39 percent, with 11 percent of voters undecided. GOP polling shows Mondale with a narrower lead.

But even some Democrats worry that Mondale's campaign is off to a rocky start. The Democratic-Farmer-Labor (DFL) Party came under heavy fire today from Gov. Jesse Ventura, an independent, Republicans and the local media for turning Tuesday night's memorial service into what often looked and sounded like a political pep rally.

Ventura, who is not seeking reelection, was booed along with Senate Minority Leader Trent Lott (R-Miss.) when their faces were shown on the overhead Jumbotron at the packed Williams Center on the University of Minnesota campus. Local television stations, which aired the event live, were flooded with complaints, and the state GOP said people were so angry that the party raised $125,000 in pledges during the 31/2-hour event.

"I feel violated that it turned into nothing more than a political rally," Ventura said. "I think the Democrats should hang their heads in shame." He threatened to appoint an independent politician to fill Wellstone's seat until Tuesday's winner can be certified and sworn in.

Jeff Blodgett, Wellstone's Senate campaign manager, apologized for the remarks of Rick Kahn, who repeatedly called on the audience to win upcoming campaigns for Democrats in Wellstone's memory. "I deeply regret if anyone took offense or was taken by surprise at some of the content," Blodgett said outside the Wellstone headquarters, where a memorial shrine continues to grow and draw visitors. "I was as surprised as everyone else." Blodgett said the event was not scripted and that individuals were asked to "speak from the heart." His apology did little to allay concerns.

State GOP Chairman Ron Eibensteiner said TV stations should give equal airtime to Coleman, suggesting lengthy coverage of President Bush's expected visit to the state this weekend. A Democratic official said Mondale's fledgling campaign spent much of the day dealing with the controversy. "All hell broke loose," the official said.

The controversy may grow in the days ahead. State officials warn of a contested election, evoking memories of the Florida presidential debacle in 2000. Democrats asked the state Supreme Court to stop the distribution of absentee ballots containing Wellstone's name, and allow those who have already cast ballots for Wellstone the chance to vote again.

State law calls for absentee votes for Coleman to count, but those for Wellstone to be discarded. People who voted by absentee ballot for Wellstone will be permitted to show up on Election Day to back another candidate. At least one Minnesota county has sent absentee ballots to replace the earlier ones, allowing voters to write in a candidate's name. Democrats want that done statewide.

Amid all the maneuvering, Coleman resumed campaigning early today, traveling on a small plane to northern Minnesota, attending a Republican rally in St. Paul and shaking hands with people attending the Bob Dylan concert later in the evening.

Coleman, who was locked in a bitter race with Wellstone, said Mondale should present his vision for the 21st century.

GOP strategists said Coleman and the party will take aim at Mondale's record as vice president and 12 years in the Senate and imply that he is past his prime as a politician. At a Republican rally at O'Gara's bar and grill in St. Paul, Coleman said, "You can either move into the future, or you can get stuck in the past." Without mentioning Mondale by name, he said, "Nothing is going to be handed to you."

Jim Dyke, a spokesman for the Republican National Committee, said Mondale's past support for tax hikes, for instance, will be a "sore spot," and Republicans will try to show he's "out of touch with the people of Minnesota in the 21st century." Democratic officials said Mondale's brief campaign will focus on Wellstone's legacy. Mondale has urged aides and others to call him by his nickname, Fritz, and supporters today sported buttons saying "One Week Fritz Blitz."

But in his speech tonight, Mondale showed voters how stark the differences are between the two leading candidates.

Mondale delighted the crowed by vowing to protect a woman's right to choose, fight tax breaks for the rich and oppose unilateral military action in Iraq. "Iraq is dangerous, but going it alone is dangerous, too. We have a United Nations; let's use it," Mondale said. Coleman supports the president's right to strike Iraq unilaterally.

Hoping his win-it-for-Wellstone campaign will help other Democratic candidates, Mondale plans to travel the state with Roger Moe, the party's gubernatorial candidate, and others on the ticket.

In his speech, Mondale played up his experience, telling the crowd he will be a member of the Senate Democratic leadership team as a result of his seniority, and took a polite poke at Coleman for playing up his ties to President Bush. "I know the White House. I worked there, too," Mondale said.

Coleman has called for at least one debate, and Mondale may give his answer when he holds a news conference Thursday morning in Minneapolis, which Wellstone's two sons, David and Mark, plan to attend. Mondale also plans a radio interview and an afternoon town meeting at Macalester College in St. Paul.

If Mondale wins the election, he would become the seventh former vice president elected to Congress. The last: Minnesota's own Hubert H. Humphrey, in 1971.

Walter F. Mondale accepts the nomination by Minnesota's Democratic-Farmer-Labor Party to run for the Senate.Republican Senate candidate Norm Coleman, left, hugs his father, Norm Sr., during a campaign event at Holman Field in St. Paul.