-- President Bush acknowledged Minnesota's mourning today and then plunged his prestige into the race to defeat former vice president Walter F. Mondale's Senate bid, topping off an unprecedented presidential investment in a midterm election.

Bush's aides had hesitated to inject him into the six-day campaign between Mondale, who replaced the late Sen. Paul D. Wellstone on the ballot, and the Republican recruited by Bush last year, former St. Paul mayor Norm Coleman.

Today's long-planned get-out-the-vote rally for Coleman, 53, was briefly scratched from Bush's itinerary after Wellstone, a liberal Democrat, died in a plane crash. But White House trepidation about politicking in such a delicate environment was erased by the backlash Democrats suffered because of the raucous Republican-baiting at Wellstone's funeral, which Bush did not attend.

"Just nine days ago, you lost a principled senator along with his wife and daughter and five other fellow Americans," Bush told more than 6,000 giddy Republicans who packed an ice hockey arena. "Paul Wellstone was respected by all who worked with him. He'll be missed by all who knew him."

Bush barely paused as he went on solemnly. "Now a vote is coming on," he said, to applause. "Even though your state is still in mourning, I'm here to remind people from all political parties that you have a duty to vote. In spite of the fact that people still mourn, Republicans and Democrats, independents, people who could care less about political parties have an obligation in the land of the free to go to the polls."

Coleman's campaign has been playing up the candidates' 21-year age difference -- Mondale is 74 -- by talking continually about the future. Bush adopted that tactic in a rare departure from his standard stump speech. "Believe me when I say we need fresh air in the United States Senate," he said. "The future of Minnesota rests with Norm Coleman." Bush, as is his habit, did not directly mention the Democrat in the race.

After blessing Coleman, Bush continued his midwestern swing by racing back to South Dakota for the second time in four days to bolster the GOP Senate candidate, Rep. John Thune. His race against Sen. Tim Johnson, besides being among the nation's tightest, is a priority for Bush because it has become a Plains State surrogate for the Washington battles between Bush and the state's senior senator, Majority Leader Thomas A. Daschle.

"It just seems like the other day I was here in South Dakota," Bush said mischievously in Sioux Falls. He was joined by first lady Laura Bush, who had spent the day campaigning for Thune.

Even as Bush campaigned through a grueling five-state day, his aides began trying to build insurance against the possibility that Tuesday's results might fall short.

Bush's White House took unprecedented steps to orchestrate the party's congressional races beginning shortly after his inauguration, and he personally shaped the Minnesota and South Dakota contests.

The president persuaded Thune to run for Senate over a lamb dinner in the White House. And Vice President Cheney and Bush senior adviser Karl Rove cleared the way for Coleman by leaning on Tim Pawlenty, the Minnesota House majority leader, to scrap his plans to run. Coleman, who had formed an exploratory committee to run against Gov. Jesse Ventura (I), then decided to run against Wellstone after strolling with Bush in the Rose Garden.

With a string of races remaining too close to call, the White House launched a pre-game effort to portray Tuesday's results as favorable to Bush as he prepares for his reelection race. A senior administration official made a rare visit to the press cabin of Air Force One today to try to persuade reporters to give Bush credit for any successes on Tuesday, but not to blame him for any disappointments.

"While it's important that the president create a national agenda to help give some of these people a banner to repair to, at the end of the day it's going to be the quality of the candidates, the quality of their effort and how they handle the range of issues -- of local concern, of state concern -- that's going to matter," the official said. "But the president will have an impact."

A state-by-state analysis in today's Washington Post concluded that Republicans were positioned to hold the House and Democrats appeared likely to retain control of the Senate. Offering a preview of the White House's Wednesday-morning spin, the official said, "That's always easier to try and keep something than to try and gain something."

Bush adviser Karen Hughes made a similar point on ABC's "This Week," saying twice that Bush "is not on the ballot" but helped "create a favorable climate for our candidates."

At the hockey arena, Bush's standard admonition to the GOP faithful to reach out to "discerning Democrats and independent voters" took on heightened stakes in a race that is in such flux that today the state's two largest newspapers published polls showing statistical ties. The Minneapolis Star Tribune showed Mondale with a 5-point edge, and the St. Paul Pioneer Press showed Coleman 6 points ahead. The newspapers gave opposite endorsements.

Mondale held a town meeting on a farm today and then left the campaign trail to prepare for the campaign's only debate, on Monday morning. Jim Manley, a campaign spokesman, said Bush's tribute was appreciated. "But the effect is going to be to energize Democrats to get out and work, because they see this as heavy-handed interference by the White House," he said.

Outside the arena, Mondale supporters waved "Fritz" signs and chanted, "Make jobs, not war."

White House officials intensely debated whether to go through with a trip to Minnesota. As an official put it: "The president said, 'It's up to Coleman. I want to come, but if he thinks it'll be helpful.' And Norm Coleman said, 'I think it'd be helpful. Let's wait on announcing for a couple of days.' "

Bush will land at his ranch in Texas on Monday night after 17 rallies in 15 states in 5 days.

In a final cross-country GOP campaign blitz, President Bush lends his support to Senate candidate Norm Coleman, right, during a rally in St. Paul, Minn.