In a climactic one-time debate on the morning before the election, the two laid out different stances on issues such as abortion, prescription drug benefits and Social Security.
The two candidates are battling to fill the Senate seat held by the late Paul Wellstone. The former vice president jumped into the race last week after Wellstone was killed in a plane crash, touching off a frenzied last-minute campaign for a seat both parties desperately want in the fight for control of the Senate.
In a related development, Gov. Jesse Ventura named fellow Independence Party member Dean Barkley as interim senator, leaving the Senate split 49-49 with two independents.
Ventura made clear he was angry that his party's Senate candidate, Jim Moore, was excluded from the debate.
"Today, three very powerful institutions, the Republican Party, the Democratic-Farmer-Labor-Party, and the Minnesota media are conspiring to limit the hard-earned rights of ordinary citizens," Ventura said.
It was unclear how long the temporary appointee would serve. Although officials initially said the person would serve until election results are certified in mid-November, some now believe the term would run into early January.
After Wellstone was killed in a plane crash Oct. 25, Ventura first said he preferred to appoint a Democrat to hold the seat since Wellstone was a Democrat. After a memorial service for Wellstone turned raucously partisan, though, Ventura said angrily that he would consider appointing an independent instead.
Much of the first part of the debate focused on whether Coleman, a Democrat-turned-Republican former mayor of St. Paul who was picked for the race by President Bush, would be a puppet for the Bush Administration.
Mondale called Coleman's campaign "the poster child for what is wrong in politics," citing its reliance on money from corporations and special interest groups.
"I can be independent," Mondale said. "I owe no one when I go to Washington."
Coleman later said he disagreed with the White House on issues such as keeping Cuba cut off from trade with the United States and opening up the Arctic National Wildlife Refuge to drilling.
"If I win on Tuesday, the president is going to owe me big time," Coleman said. "We walked through fire to get here."
The two repeatedly clashed on tax strategies. Mondale said the Bush tax plan Coleman supports provides most of its relief to the nation's wealthiest one percent. He said he'd support tax cuts for the middle class.
Coleman several times noted that the U.S. raised taxes when Mondale was vice president in the late 1970s. But when Coleman noted that Mondale in his 1984 presidential campaign told voters more tax increases were needed to lower the government's debt, Mondale pointed out that President Reagan raised taxes after beating him.
"I was the one who told the truth before the election," Mondale said. "And I think that's one of the big things Minnesotans have to look at: Who's got the courage to stand up, level with the people, even when it's difficult?"
The debate was the only face to face meeting between Coleman and Mondale, who was nominated last Wednesday to run in place of Sen. Paul Wellstone, who was killed in a plane crash five days earlier in northern Minnesota.
After halting his campaign the day of Wellstone's crash, Coleman resumed last Wednesday with a new focus: emphasizing his youth and energy level though only rarely contrasting it with Mondale.
He began the debate saying the election was "not about Vice President Mondale's age. It's not about my age. It's about the age we live in."
As Mondale went on to list differences on issues, Coleman said, "This is the tone we don't need in Washington. I was a Republican mayor in a Democratic city and we worked together and got things done without the kind of tone that you're using."
But Mondale said, "What you're doing is sticking with the right wing and pretending to change the tone."
He later added, "This is not about tone. I've always been for civil debate. This is about fundamental principles."
After the debate, Coleman told reporters, "The tone you heard there is the reason Minnesotans are still waiting for a lot of things."
Mondale told reporters campaigns are not a "tea party."
"One of his strategies here was to cover up the differences by an appeal like the kind he used," he said. "The fact is we do have these differences. The public needed to know about them and we had to be direct in order to do it."
The race between the two men is very close. On Sunday, two new polls produced a conflicting picture of who leads the race. Mondale had 46 percent to 41 percent for Coleman in a Minneapolis Star Tribune poll. The poll's margin of sampling error was plus or minus 3 percentage points.
But another Sunday poll, conducted for the Pioneer Press/Minnesota Public Radio, showed Coleman with 47 percent to 41 percent for Mondale, with a margin of error of 4 percentage points. The Star Tribune poll surveyed 929 likely voters Wednesday through Friday. The Pioneer Press poll surveyed 625 likely voters for the same period.
"The people have been on an emotional roller coaster, so this is going to be a hard one to judge from polls," Mondale campaign manager Tina Smith said. One poll had 9 percent undecided, the other 10 percent, reinforcing the notion of a race that could go either way on Tuesday.