Biden, ahead of midterms, marks Labor Day in election battleground states

President Joe Biden, who prides himself as being a pro-union president, on Labor Day kicked off the the unofficial start of the fall campaign season ahead of the midterm elections with two cross-country stops in battleground states.

Biden made what the White House called official remarks "celebrating Labor Day and the dignity of American workers" in Wisconsin and Pennsylvania after a string of legislative victories and a slight bump in approval ratings.

In both swing states, Democrats are facing high-stakes, heavily-funded midterm races.

In heading to those states for Labor Day, Biden mirrored the strategy of his Democratic predecessors Barack Obama and Bill Clinton.

Biden traveled first to Milwaukee for its Labor Day celebration, Laborfest, with Democratic Gov. Tony Evers -- up for reelection in November against Republican Tim Michels.

Biden spent most of his nearly half-hour speech focused not only on worker contributions and touting his legislative achievements but also repeating his recent criticism of "MAGA Republicans" and former President Donald Trump.

He said voters had a moral responsibility to uphold American democracy during the coming midterm elections.

"Extreme MAGA Republicans don't just threaten our personal rights and our economic security, they embrace political violence," he said.

"As I said last week, we remain in the battle for the soul of America," he said.

In doing so, Biden resurrected his 2020 "battle for soul of the nation" message that he said inspired his bid for the White House after white nationalists clashed with counter protesters in Charlottesville, Virginia, in 2017. He also used the messaging during a prime-time speech Thursday in Philadelphia.

Lt. Gov. Mandela Barnes -- a Democratic Senate hopeful in a tight race against incumbent GOP Sen. Ron Johnson -- did not accompany Biden at the Milwaukee event, despite attending the city's earlier Labor Day parade with Evers. Wisconsin Sen. Tammy Baldwin was also did not attend, even though she is not up for reelection until 2024.

"I want to thank Tammy. She couldn't be here today, who is a champion of work and people and always there. You know, and the same goes for lieutenant governor Mandela Barnes who couldn't be here. He's gonna be your next United States senator," Biden said.

Biden painted a stark divide between the recent legislative achievements of Democrats over his term and Republican efforts to undermine their efforts. He became noticeably fired up talking about the Inflation Reduction Act and the measures included to bring down prescription drug prices.

"For decades Big Pharma won year in and year out because they own chunks of the Congress. Because they had the help, like your senior senator, Ron Johnson," Biden said, drawing boos from the crowd.

"Not this year! We beat Pharma this year! We beat Pharma this year and it mattered! We are gonna change people's lives," Biden said, outright shouting "We beat Pharma!"

Ahead of Biden's visit, Republican National Committee and the Wisconsin Republican Party hosted a Zoom call, slamming the president's Thursday primetime speech in Philadelphia and his recent moves to cancel up to $20,000 in student loan debt.

Johnson was on the Zoom call, calling the president "no moderate" and that he has become a "divider-in-chief." Johnson noted that his Democratic opponent has been "in hiding" and that Barnes has not been doing any recent press conferences. One of Barnes' most recent events was a meet and greet with seniors on Aug. 29 on the subject of Social Security and Medicare, in response to recent Johnson comments on potentially cutting those programs.

But Biden also cleared the distinction between establishment Republicans and "MAGA Republicans," noting that the latter's "extreme ideology" has moved to create political violence and disenfranchisement within the party and an inability to work across the aisle.

"I want to be very clear up front. Not every Republican is a MAGA Republican. Not every Republican embraces that extreme ideology. I know because I've been able to work with mainstream Republicans my whole career. But the extreme MAGA Republicans in Congress have chosen to go backwards full of anger, violence, hate and division, but together we can and we must choose a different path, forward," Biden said.

Biden also notably embraced a new term during his Milwaukee speech, calling MAGA Republicans "Trumpies," when making a point about GOP Sen. Rick Scott's plan to reauthorize Social Security every five years.

"The biggest contrast from what MAGA Republicans, the extreme right, the Trumpies, they want to go to Congress. These MAGA Republicans in Congress are coming for your social security as well," Biden warned.

From Milwaukee, Biden traveled to West Mifflin outside Pittsburgh where he delivered remarks to a much smaller crowd at United Steelworkers of America Local Union 2227 -- the third time the president has visited the commonwealth in one week.

He appeared with Pennsylvania's Democratic Lt. Gov. John Fetterman who is in a battle for retiring Republican Sen. Pat Toomey's Senate seat against Trump-endorsed Dr. Mehmet Oz.

In a tweet, Fetterman's director of communications said that the candidate would appear with Biden -- the first time the candidate has joined the president during his weeklong span of the state -- with plans to discuss marijuana decriminalization.

“If I have to be in a fox hole, I want John Fetterman in there with me. I’ll tell you what, I want John in there with me. I mean that sincerely,” Biden said to applause.

He again called out "MAGA Republicans."

“Trump and the MAGA Republicans made their choice. We can choose to build a better America or we can continue down this sliding path oblivion to where we don't want to go,” Biden said. "You can't love the country and say how much you love it when you only accept two outcomes from the election -- either you won or you were cheated. It doesn’t work that way."

Democratic Attorney General Josh Shapiro is also facing a tight race against Trump-endorsed Republican Doug Mastriano for governor.

On Thursday in Philadelphia, Biden, in a fiery speech, warned about what he called threats to American democracy, presenting himself and Democrats ahead of the midterms as a clear contrast to Trump and MAGA Republicans.

He pummeled Republicans participated in the Jan. 6 insurrection, those who refuse to accept the 2020 election results and want to strip away abortion rights.

"Too much of what's happening in our country today is not normal," he said. "Donald Trump and the MAGA Republicans represent an extremism that threatens the very foundations of our republic."

Vice President Kamala Harris, speaking at the Greater Boston Labor Council Annual Breakfast on Monday, echoed Biden's remarks Thursday in Philadelphia, criticizing "extremist, so-called leaders" for their attempts to "turn back the clock …To a time before workers had the freedom to organize. To a time before women had the freedom to make decisions about their own bodies. To a time before all Americans had the freedom to vote."

--ABC News' Alexandra Hutzler, Molly Nagle, Paulina Tam and Sarah Kolinovsky contributed to this report.