As President Bush addressed a rally here Wednesday, he performed the political equivalent of preaching to the choir.

Bush won a whopping 65 percent of the vote in this suburban Milwaukee county in 2000, and the Republican Party, which dispensed tickets for the open-air speech, made sure the fairgrounds were packed with Bush loyalists.

Rosemary Metzdorff, after cheering her way through a speech full of references to abortion restrictions, tax cuts, caps on jury awards and other conservative favorites, could not decide which part she liked best. "Every part -- I'm such a Bush fan," she replied, adding that the president probably did not change many minds here. "They were all for him, anyway."

Therein lies an important key to understanding Bush's reelection strategy. Although age-old campaign rules dictate that the general-election candidate must emphasize moderate "swing" voters and political independents, Bush strategists are predicting that this election, more than previous ones, will be determined by the turnout of each side's partisans. Although not discounting swing voters, Bush is placing unusual emphasis so far on rallying the faithful.

"In close elections in today's environment, the old political strategy of focusing just on independents won't work," said Matthew Dowd, the Bush campaign's chief strategist. "Campaigns have to motivate supporters at the same time of appealing to swing voters."

There is evidence to support the Bush theory. A study by the nonpartisan Pew Research Center found that 21 percent of registered voters are undecided or might change their minds -- at this point in 2000, it was 32 percent. Still, Pew reasoned, "the swing vote, while smaller in relative terms, is still substantial and certainly large enough to propel either of the presidential candidates to a big victory."

Democrats say Bush's approach is novel. "It's a new way to run for president," said James Carville, the strategist behind Bill Clinton's 1992 victory. Whereas "usually you quietly shore up your base and aggressively court the swing voter, Bush is aggressively shoring up his base and quietly courting the swing voter."

Some Bush allies say it is more efficient to boost turnout among partisans than to sway the fence-sitters, who the campaign believes may be 10 percent of the electorate or less. "How much time and energy do you give to picking up the 10 percent, who are disengaged from politics, and how do you communicate with them even if you want to?" asked Grover G. Norquist, president of Americans for Tax Reform. "You can go to the 45 percent [who already support Bush] and ask them to bring a brother or a sister or a friend to the polls."

This is not to say that Bush has forgotten the wisdom of appealing to undecided voters in the center, or that Sen. John F. Kerry does not spend time courting the Democrats' left wing. On Tuesday, for example, Bush visited Democratic strongholds in Michigan and Minnesota, trying to woo former Reagan Democrats by appealing to their conservative social values. And the Republican convention this summer will feature moderates, including Sen. John McCain (Ariz.) and former New York mayor Rudolph W. Giuliani.

Dowd said the campaign is targeting swing voters and GOP partisans simultaneously with talk about tax cuts and the war on terrorism. "The campaign's resources from the very beginning are designed to do both these aspects efficiently and effectively," he said. "The good news for the Bush campaign is that we can do both without having a conflict."

Without question, Bush's choice of rhetoric and audience represents a more overt appeal to conservatives than he made in the 2000 race. Then, he scolded conservatives who had a "leave us alone" philosophy, and he regularly referred to himself as a "compassionate conservative" -- implying that other conservatives were not compassionate.

Polls show that Bush has the support of 90 percent of Republicans, which his campaign says is the highest of any incumbent in 30 years. But partly because of the experience of Bush's father in 1992 and partly because fewer evangelical Christians turned out to vote in 2000 than Bush's experts had forecast, the White House and the Bush campaign remain concerned about his conservative support. Bush championed a constitutional amendment to ban same-sex marriage, risking a backlash from moderate voters, and economic conservatives have complained about the budget deficits that roared back under this administration.

Kerry is still working to shore up support among Hispanics and African Americans but has a base that is largely unified by anti-Bush fervor -- so much so that he has raised money faster than Bush and has been able to adopt conservative rhetoric on some issues with no outcry from his core supporters.

That leaves him free to court swing voters. On Thursday, Kerry will fly to suburban Philadelphia to kick off a Front Porch Tour, to continue through the election, in which Kerry's ticket will promote plans for health care, education and middle-class tax relief under the rubric of "hometown values."

Bush, by contrast, inaugurated a new format for his road show last week, inviting cameras to meetings in North Carolina and Michigan in which he railed against Democrats for holding up his judicial nominees -- an issue dear to social conservatives but unlikely to motivate typical voters. Next came a Pennsylvania bus tour, which Sen. Arlen Specter (R-Pa.) described aboard Air Force One as "an effort to stimulate the base in . . . solid Republican counties."

Friday, Bush will speak in Tampa to a national conference on the dangers of the international trade in sex slaves and other forms of human trafficking -- an issue that is important to some Christian groups. At the same time, Bush turned down an invitation to speak last weekend to the NAACP, the nation's largest and oldest civil-rights organization.

Selecting friendly audiences is standard operating procedure for any campaign. But Kerry's campaign on Tuesday issued a statement complaining about Bush restricting access to campaign events, citing news accounts about people being turned away from Bush events because they were not supporters. A Kerry spokesman, Phil Singer, said those who attend Kerry rallies are not asked about their loyalties.

Bush's appeal to Republican partisans was on display Wednesday, on his 12th visit as president to a state he lost to Vice President Al Gore by 5,708 votes. After his stop in suburban Milwaukee, Bush visited two other friendly towns: Fond du Lac, where he earned 57 percent of the vote; and Green Bay area Ashwaubenon, where he beat Gore by 5 percentage points. Writing about Bush's bus tour, the Milwaukee Journal Sentinel observed Wednesday: "In the course of a few hours' drive, President Bush will blanket his political base."

Candidates for the GOP nomination to run against Sen. Russell Feingold (Wis.) worked the party faithful at Bush's stops. "This is probably the biggest Republican county in the state," candidate Tim Michels observed in Waukesha.

The crowd delighted in Bush's stream of Kerry-directed barbs, laughing and applauding when Bush said: "If you disagree with John Kerry on most any issue, you may just have caught him on the wrong day." The audience booed when Bush derided Kerry as a liberal and mocked Kerry's assertion that he represents "conservative values." They cheered his criticism of "sophisticates" and "entertainers from Hollywood."

Bush recited a list of conservative priorities, including help for religious groups and new judges, and opposition to abortion. "We're strong because of the institutions that help give us direction and purpose: our families, our schools, our religious congregations," Bush said in Waukesha.

In Fond du Lac, some of the best-received remarks were Bush's praise for religion -- "love comes from our religious congregations" -- and opposition to same-sex marriage. "Marriage between a man and woman is an important part of stable families," he said. He had to pause for the applause to subside.

Allen reported from Washington.

President Bush campaigns in Waukesha County, Wis., where a majority voted for him in 2000. Recent polls show that 90 percent of Republicans support him.President Bush rallies the Republican faithful in Waukesha, Wis.