President Joe Biden excoriated “MAGA Republicans” and the extreme right on Monday, pitching personal Labor Day appeals to swing-state union members who he hopes will turn out in force for his party in November.

“The middle class built America,” Biden told a workers’ gathering at park grounds in Milwaukee. “Everybody knows that. But unions built the middle class.”

Later Monday, he flew to West Mifflin, outside Pittsburgh — returning to Pennsylvania for the third time in less than a week and just two days after his predecessor, Donald Trump, staged his own rally in the state.

The unofficial start of fall, Labor Day also traditionally starts a political busy season where campaigns scramble to excite voters for Election Day on Nov. 8. That’s when control of the House and Senate, as well some of the country’s top governorships, will be decided.

Trump spoke Saturday night in Wilkes-Barre, near Scranton, where Biden was born. The president made his own Wilkes-Barre trip last week to discuss increasing funding for police, to decry GOP criticism of the FBI after the raid on Trump’s Florida estate and to argue that new, bipartisan gun measures can help reduce violent crime.

Two days after that, Biden went to Independence Hall in Philadelphia for a prime-time address denouncing the “extremism” of Trump’s fiercest supporters.

Trump has endorsed candidates in key races around the country and Biden is warning that some Republicans now believe so strongly in Trumpism that they are willing to undermine core American values to promote it. The president said Thursday that “blind loyalty to a single leader, and a willingness to engage in political violence, is fatal to democracy.”

Trump responded during his Saturday rally that Biden is “an enemy of the state.” Republican National Committee Chair Ronna McDaniel tweeted Monday that Biden “is the most anti-worker president in modern history,” noting that high inflation had taken a bite out of American wages, income and savings.

During his address in Milwaukee, Biden said “Not every Republican is a MAGA Republican” but singled out those who have taken Trump’s “Make America Great Again” campaign cry to dangerous or hateful lengths. He highlighted episodes like last year’s mob attack on the U.S. Capitol.

He said that many in the GOP are “full of anger, violence, hate, division.”

“But together we can, and we must, choose a different path forward,” Biden said. “A future of unity and hope. we’re going to choose to build a better America.”

The crowd jeered loudly as the president repeatedly chided Republican Sen. Ron Johnson of Wisconsin for voting against a Democratic-backed measure meant to lower prescription drug prices. The president also suggested Johnson and other congressional Republicans were willing to undermine Social Security.

Unions endorsements helped Biden overcome disastrous early finishes in Iowa and New Hampshire to win the 2020 Democratic primary, and eventually the White House. He has since continued to praise the labor movement as president.

Mary Kay Henry, president of the 2 million-member Service Employees International Union, called Biden’s championing of unions heading into the midterm elections “critical” and said workers must “mobilize in battlegrounds across the country to ensure that working people turn out.”

“We’re really excited about the president speaking directly to workers about, if he had the opportunity, he’d join a union,” Henry said. She added: “This president has signaled which side he’s on. And he’s on the side of working people. And that matters hugely.”

In Pennsylvania, Biden addressed members of the United Steelworkers and noted that Trump is a “former, defeated president.”

Referencing Trump’s persistent, false claims of fraud in the 2020 presidential election, Biden said, “You can’t love the country and say how much you love it when you only accept one of two outcomes of an election: Either you won or you were cheated.”

Both of the perennial presidential battleground states Biden visited Monday may provide key measures of Democrats’ strength before November. With inflation still raging and the president’s approval ratings slightly better but remaining low, how much Biden can help his party in top races — and how much candidates want him to try — remains to be seen.

That was on display in Milwaukee, where Democratic Lt. Gov. Mandela Barnes is trying to unseat incumbent Johnson, but didn’t appear with Biden.

In the state’s other top race, Tim Michels, a construction executive endorsed by Trump, is attempting to deny Democratic Gov. Tony Evers a second term. Evers spoke at the labor event Biden addressed and briefly greeted the president backstage.

“We have a president who understands the challenges facing working families,” Evers told the crowd. He said Biden “hasn’t forgotten that working families matter, not just on Labor Day, but every single day of the year.”

Pennsylvania voters are choosing a new governor, with state Attorney General John Shapiro facing another Trump-endorsed Republican, Doug Mastriano, and a new senator. That race is between Democratic Lt. Gov. John Fetterman and Trump-backed celebrity heart physician Mehmet Oz. Fetterman spoke with Biden before both gave speeches in West Mifflin.

The Pennsylvania and Wisconsin races could decide which party controls the Senate next year, while the winner of each governorship may influence results in 2024′s presidential election. The stakes are particularly high given that some Trump-aligned candidates have spread his lies about widespread fraud that did not occur during the 2020 election. Judges, including ones appointed by Trump, dismissed dozens of lawsuits filed after that election, and Trump’s own attorney general called the claims bogus.

Vice President Kamala Harris paid tribute to organized labor in at breakfast meeting with the Greater Boston Labor Council, declaring “When union wages go up, everybody’s wages go up.”

“When union workplaces are safer everyone is safer,” Harris said. “When unions are strong, America is strong.”

(AP)