JANESVILLE, Wis. — The danger signs are mounting for Donald Trump in Wisconsin: Right-wing radio hosts are flaying him, Gov. Scott Walker and other elected Republicans have endorsed Sen. Ted Cruz, and a new poll showed Cruz with a 10 percentage-point lead in the state before Tuesday's primary.
The Stop Trump movement may never have another opportunity like the one here, where resistance to Trump was running high even before his campaign became consumed by a new round of controversies, from his mocking of Cruz's wife to the arrest of his campaign manager to his comments in favor of punishing women who get abortions.
If Trump is dealt a setback in the Wisconsin primary, including a potential sweep by Cruz of all 42 delegates, it would be his most prominent reversal since his second-place finish in the Iowa caucuses in February. And it would show Trump's vulnerability before the race moves to New York and other Northeastern states.
The state's Republican establishment, cohesive and battle-tested after years of partisan warfare under Walker, has dug in to support Cruz — not out of true love for the Texas senator, but in a marriage of convenience to halt Trump, whose temperament and conservatism many doubt.
But at the same time, if the forces arrayed against Trump do not prevail in Wisconsin, they are unlikely to slow Trump in the ideologically more favorable turf of the East, increasing his chances of locking down the nomination before the July national convention.
A poll released Wednesday by Marquette University Law School showed Cruz leading the Republican field with 40 percent and Trump with 30 percent, a reversal from a month earlier when Trump held a 10-point lead. Gov. John Kasich of Ohio was third, with 21 percent.
A Cruz victory would suggest that a backlash against Trump has set in after a series of nasty episodes, including his insults of Heidi Cruz and the arrest of Corey Lewandowski, Trump's campaign manager, on a charge of manhandling a female reporter.
Cruz went further than ever before Tuesday during a CNN town hall in Milwaukee, where he suggested he would not support Trump if he became the party's nominee.
"It's gotten really ugly," Cruz said. "What lesson do our kids take watching us?"
Earlier he said the battery charge filed in Florida against Lewandowski should be "a fireable offense."
With Trump adamantly defending Lewandowski as the victim in the encounter, after video evidence contradicted the manager's earlier charge that the reporter was "delusional," Cruz said, "Nominating Donald Trump would be an absolute train wreck."
Trump's unfavorable rating in the Marquette poll, conducted before Lewandowski's arrest, was 70 percent. Only 24 percent of women planning to vote in the Republican primary backed Trump, fewer than for the other two candidates.
Still, Trump has many advantages in Wisconsin, including its large number of white working-class voters, a group that has flocked to him throughout the campaign, and a passionate base of supporters for whom he can do no wrong. He plans a heavy schedule of appearances through the weekend.
Thousands waited more than two hours Tuesday to hear him in Janesville during the candidate's first visit to the state. At the rally, he belittled Walker for his record and even his love for Harley-Davidson motorcycles. "He doesn't look like a motorcycle guy to me, I'm sorry," Trump said to laughter.
Neither women nor men waiting to hear him, many of whom bought Trump hats, buttons and shirts from vendors working the crowd like a Green Bay Packers game, said they were unsettled by Trump's derogatory remarks about women.
"I think he calls 'em as he sees 'em," said Mae Pospeschil, a title searcher from Beloit.
Unlike in neighboring Illinois and Michigan, Midwestern industrial states where Trump had strong victories, the race in Wisconsin is much tighter, in part because of sharp regional differences among Republicans.
Voters in the Milwaukee suburbs, the reddest counties in the state, hold highly negative views of Trump, according to a polling analysis by The Milwaukee Journal-Sentinel. Voters in northern and western counties are more slightly favorable to Trump, the Marquette poll showed.
Ed Goeas, a pollster who works for an anti-Trump super PAC that is hammering him with television ads in Wisconsin for insulting women, said married Republican women were turning against the New York businessman.
"I see an opportunity for us to have Trump walk out of there with no delegates," Goeas said. With no Republican nominating contests for two weeks after Wisconsin votes, a Trump defeat could change the tenor of the race.
"The narrative that comes out of Wisconsin has a huge impact," Goeas said.
Trump is struggling in the suburbs with its more affluent and better educated voters, the heart of Walker territory, which sustained the governor in a bitter recall election in 2012 and his re-election in 2014. "The Republican base still loves Scott Walker," said Tom Schreibel, a former chief of staff for Rep. Jim Sensenbrenner, a Republican who represents the region. "The further you get from major metropolitan areas, Trump gets stronger."
Another factor in the race is the influence of the state's right-wing talk radio, which has been anti-Trump.
Charlie Sykes, a radio host in Milwaukee, who derisively calls Trump supporters "Trumpkins" for their unquestioning loyalty, subjected Trump to a punishing interview this week. "Remember, we're not on the playground," he chided the businessman over his insults of Cruz's wife. "We're running for president of the United States."
The regional differences matter because of how Wisconsin awards delegates. Three go to the winner of each of the state's eight congressional districts. Eighteen more are awarded to the winner of the statewide vote.
Cruz has brought his most intensive retail effort to the state since the early nominating contests in Iowa and South Carolina, campaigning in Wisconsin for a week and setting up a "Camp Cruz" for volunteer door knockers in the Milwaukee suburbs.
"Wisconsin will be a solid example of our campaign's ability to run a single-state race, much like Iowa," which Cruz won, his campaign pollster, Chris Wilson, said in an interview.
But Cruz's efforts are threatened by Kasich. The Cruz campaign says Kasich will siphon off anti-Trump votes and hand Trump the three delegates from some districts.
Recognizing the threat, a pro-Cruz super PAC began a harsh anti-Kasich radio ad campaign in the state Tuesday.
Kasich's campaign rejects the charge that he is a spoiler. It maintains that he is strong enough to win two or three districts in Wisconsin: around Madison, the liberal state capital; and the close-in Milwaukee suburbs, where Kasich campaigned Tuesday. The Marquette poll showed Kasich leading in the Madison media market.
"I think that if Kasich is not in, Donald would win altogether more delegates than with Kasich involved," said Tommy Thompson, a former Wisconsin governor, who is chairman of Kasich's campaign in the state. Like other Kasich supporters, he is banking on the Ohio governor emerging as the consensus nominee in an open convention as the best choice to defeat a Democrat in November.
"It's short game versus long game," he said.