U.A.W. Strike Live Updates: Walkouts Hit Auto Plants for the Big Three

“Over generations, autoworkers sacrificed so much to keep the industry alive and strong, especially the economic crisis and the pandemic,” Mr. Biden said. “Workers deserve a fair share of the benefits they helped create.”

Mr. Biden said that Julie Su, the acting secretary of labor, and Gene Sperling, a top White House economic adviser, would go to Michigan immediately to try to bring both sides back to the bargaining table. But he said the automakers “should go further to ensure record corporate profits mean record contracts for the U.A.W.”

For decades, Mr. Biden has been an unapologetic backer of unions who rejects even the approach of some Democrats when it comes to balancing the interests of corporate America and the labor movement.

During the past several years, he has helped nurture what polls suggest is a resurgence of support for unions, as younger Americans in new-economy jobs push for the right to organize at the workplace. Mr. Biden declares that “unions built the middle class” in virtually every speech he delivers.

“That was most pro-union statement from a White House in decades, if not longer,” Eddie Vale, a veteran Democratic strategist who worked for years at the A.F.L.-C.I.O., said after the president’s remarks.

The president’s decision to weigh in on the side of the union without much reservation will most likely to draw fierce criticism from different quarters. Earlier in the day — even before the president’s White House comments — Suzanne P. Clark, the head of the U.S. Chamber of Commerce, issued a searing statement blaming the strike on Mr. Biden for “promoting unionization at all costs.”

After Mr. Biden’s remarks, Neil Bradley, the group’s top lobbyist in Washington, said the president’s message and the pro-union policies his administration has pursued have “emboldened these demands that just aren’t grounded in reality.”

And in a possible preview of a rematch with former President Donald J. Trump, NBC on Friday aired part of an interview in which Mr. Trump sided just as forcefully with the car companies against the unions.

“The autoworkers will not have any jobs, Kristen, because all of these cars are going to be made in China,” Mr. Trump said in an interview set to air Sunday on the network’s “Meet the Press” program. “The autoworkers are being sold down the river by their leadership, and their leadership should endorse Trump.”

Friday’s walkout by the U.A.W. is in some ways a broader test of Mr. Biden’s economic agenda beyond just his pro-union stand. It also touches on his call for higher wages for the middle class; his climate-driven push to reimagine an electric vehicle future for car companies; and his call for higher taxes for the wealthy. The strike is centered in Michigan, a state that the president practically must win in 2024 to remain in the Oval Office.

“You’ve got rebuilding the middle class and building things again here,” Mr. Vale said. “You’ve got green energy, technology and jobs. You’ve got important states for the election. So all of these are sort of together here in a swirl.”

At the White House, Mr. Biden’s aides believe the battle between the car companies and its workers will underscore many of the president’s arguments about the need to reduce income inequality, the benefits of empowered employees, and the surge in profits for companies like the automakers that makes them able to afford paying higher wages.

That approach is at the heart of the economic argument that Mr. Biden and his campaign team are preparing to make in the year ahead. But it sometimes comes into conflict with the president’s other priorities, including a shift toward electric vehicles.

Mr. Biden’s push for automobiles powered by batteries instead of combustion engines is seen by many unions as a threat to the workers who have toiled for decades to build cars that run on gas. The unions want factories that make electric cars — most of which are not unionized — to see higher wages and benefits too.

So far, Mr. Biden has sidestepped the question of whether his push for a green auto industry will hasten the demise of the unions. But Friday’s remarks are an indication that he remains as committed as ever to the political organizations that have been at the center of his governing coalition for years.

In his remarks on Friday, he hinted at the tension inherent in the technological transition from one mode of propulsion to another.

“I believe that transition should be fair, and a win-win for autoworkers and auto companies,” he said. But he added: “I also believe the contract agreement must lead to a vibrant ‘Made in America’ future that promotes good, strong middle class jobs that workers can raise a family on, where the U.A.W. remains at the heart of our economy, and where the Big Three companies continue to lead in innovation, excellence, quality and leadership.”

The targeted strike is designed to disrupt one of America’s oldest industries at a time that Mr. Biden is sharpening the contrast between what rivals and allies call “Bidenomics” and a Republican plan that the president warns is a darker version of trickle-down economics that mostly benefits the rich.

“Their plan — MAGAnomics — is more extreme than anything America has ever seen before,” Mr. Biden said on Thursday, hours before the union voted to strike.

Mr. Biden was joined on Friday by several of the more liberal members of his party, who assailed the automakers and stood by the striking workers.

Representative Alexandria Ocasio-Cortez, Democrat of New York, sent out a fund-raising appeal accusing the companies of refusing “to meet the demands of workers negotiating for better pay” despite having “netted nearly a quarter trillion dollars in profit over the last decade.”

Senator Sherrod Brown, an Ohio Democrat, visited striking Jeep workers at a Toledo plant that makes the popular Wrangler sport-utility vehicle and declared that “Ohioans stand in solidarity with autoworkers around our state as they demand the Big Three automakers respect the work they do to make these companies successful.”

How Mr. Biden navigates the strike and its consequences could have a significant impact on his hopes for re-election. In a CNN poll earlier this month, just 39 percent of people approved of the job he is doing as president and 58 percent said his policies have made economic conditions in the United States worse, not better.

The fact that the strike is centered in Michigan is also critical. Mr. Biden won the state over Mr. Trump in 2020 with just over 50 percent of the vote. Without the state’s 16 electoral votes, Mr. Biden would not have defeated his rival.

Unlike previous strikes involving rail workers or air traffic controllers, Mr. Biden has no special legal authority to intervene. Still, he is not exactly just an observer either.

Just before the strike vote, Mr. Biden called Shawn Fain, the president of the U.A.W., as well as top executives of the car companies. Aides said that the president told the parties to ensure that workers get a fair contract and he urged both sides to stay at the negotiating table.

Economists say a lengthy strike, if it goes on for weeks or even months, could be a blow to the American economy, especially in the middle of the country.

Still, the president is unwavering on policies toward both unions and the environment. In a Labor Day speech in Philadelphia, Mr. Biden renewed both his vision about what he called a “transition to an electric vehicle future made in America” — which he said would protect jobs — and his rock-solid belief in unions.

“You know, there are a lot of politicians in this country who don’t know how to say the word ‘union,’” he said. “They talk about labor, but they don’t say ‘union.’ It’s ‘union.’ I’m one of the — I’m proud to say ‘union.’ I’m proud to be the most pro-union president.”