MILWAUKEE - As recently as last week, Barbara White was fretting that the presidential primary race in Wisconsin was way too quiet.

"They've got to start engaging us," the longtime Democratic activist said of the presidential candidates and campaigns.

As if on cue, last Tuesday Michelle Obama, Barack Obama's wife, swept into the diner where White and a handful of other Democrats had been waiting and proceeded to do some old-fashioned campaigning.

"I just want to keep talking to folks on the ground," Obama told a hand-picked group of working mothers who she said were on the wrong side of the gap between "the lucky few and ordinary people. ... Barack and I are still close to the realities you face."

White was satisfied with what she heard. "It may be late, " she said, "but it looks like this state's going to count this year."

That it does.

On Tuesday, Wisconsin's voters have their chance to shape the still-unsettled contours of the presidential race. Obama has a chance to extend a string of victories over Hillary Rodham Clinton, while she has the opportunity to arrest his momentum. John McCain can pad his overwhelming lead in GOP delegates, while Mike Huckabee hopes for another conservative-fueled upset.

Important region

If recent presidential elections are instructive, the three-state axis of Wisconsin, Minnesota and Iowa could prove pivotal this year, having been one of the most competitive regions in the nation.

Voters in Iowa and Minnesota have already given a big boost to Obama, while their Republican verdict has been more muddied.

Seeking the edge in Wisconsin, Obama campaigned in the state for two days earlier this week, while Clinton campaigned Sunday after letting her husband and daughter stump for her. In the Republican race, Huckabee barnstormed the state for several days; McCain had a single stop on Friday.

Wisconsin, which used to hold its presidential primary in April, moved it to mid-February before the 2004 election, but there was no serious effort to join the crowd of states that voted on Super Tuesday. That risked making this year's primary irrelevant, but the absence of an absolute knockout punch in either party on Feb. 5 erased that risk.

Historic role

Historically, Wisconsin's role in picking presidents has been outsized, from the crucial boost it gave John F. Kennedy over Minnesota's Hubert Humphrey in 1960 to Lyndon Johnson's decision to drop out of the race days before the 1968 primary when polls showed him badly trailing another Minnesota senator, Eugene McCarthy.

This year, little polling has been done, making the race difficult to handicap. The most recent poll, published this week, showed Obama with a slight lead over Clinton. McCain led Huckabee by a comfortable margin.

The tactical differences between the Obama and Clinton campaigns were on stark display Tuesday night. While Obama was telling 17,000 people in Madison that "tonight we're on our way. ... This is the new American majority," Clinton was telling a Milwaukee TV station, "I think we have an uphill challenge. I'm the underdog in that race."

Within hours, the Clinton campaign was on the air with an attack ad, slamming Obama for declining a debate in Wisconsin before the primary. "Maybe he'd prefer to give speeches than have to answer questions," an announcer says.

The Obama camp, which had already been advertising for weeks, fired back Thursday with an ad of its own: "It's the same old politics of phony charges and false attacks." Clinton launched two more ads Friday, attacking Obama's counterattack.

Unlike the grass-roots ground wars in the earliest states, the campaigns are relying more on personal appearances and ads. And there has been no widespread repeat of cross-border raids by Minnesota volunteers, as occurred before the Iowa caucuses.

Rivals on same turf

In Waukesha, speaking to a crowd of more than 1,000, Obama pivoted between criticizing Clinton and McCain.

He said that a McCain administration "would be the same as we've had the last seven years" and accused Clinton of flip-flopping on NAFTA, supporting it while Bill Clinton was in office, now disowning it.

Exuding confidence, he at one point inadvertently put himself in the White House already. "After a year in office -- uh, I'm not in office yet," he said. "Jumping ahead there, jumping ahead. After a year of campaigning, my bet has paid off."

Rodney Johnson brought two dozen fifth- and sixth-graders from his Milwaukee private school to hear Obama. "After hearing him today, he's got my vote," Johnson said. "He says a lot of good things, especially about education."

As for the kids, "it's important they get to see someone who looks like them," he said, referring to his black students. "And in the event he wins, it means they got to see the president of the United States. How awesome is that?"

A day later, former President Bill Clinton was in the same hall, telling about 500 people that his wife's Senate experience would lead to growth in jobs and the attainment of universal health care. "It's about whether you should choose the power of speeches over the power of solutions," he said.

Republicans hit the trail

Among the Republicans, McCain scheduled a couple of last-minute stops on Friday, while Huckabee hopscotched across the state for three days, meeting a few hundred spectators at a time.

In Waukesha, referring to last Tuesday's Potomac Primaries, Huckabee said McCain "won the Beltway, while we've won the states that are important to Republicans in November. A lot of people in the heartland say they don't need anymore of Washington."

Acknowledging the mathematical impossibility of his winning the GOP nomination in the primary season, Huckabee said: "What could happen is that neither one of us gets 1,191 [delegates]. Then it goes to the convention and all bets are off. This game's still on."

Several Huckabee supporters came to give him something of a valedictory sendoff, and their antipathy toward McCain was palpable.

"A lot of so-called conservatives aren't recognizing Huckabee and that's made people mad as little wet hens," said Gary Anderson, a retiree who drove up from Chicago to see him. "They're trying to scrub McCain hard enough to make him look conservative, but all they're saying is that outsiders aren't welcome."

John Meiners, a contractor from Wausheka, said Huckabee's loss in Virginia last week "was the last nail in the coffin. He gave it his best shot and if it's over, it's over. I'm not too crazy about John McCain, but he'd certainly be better than Hillary or Obama."

The Associated Press contributed to this report. Bob von Sternberg • 612-673-7184