The United Automobile Workers union endorsed President Biden on Wednesday, delivering an influential boost as he faces a battle against former President Donald J. Trump to win the support of labor groups.
Mr. Biden, who calls himself the “most pro-union president in history,” delighted striking U.A.W. workers but angered auto industry executives when he appeared on a picket line with workers last fall. Months later, Shawn Fain, the U.A.W. president, told a national conference of workers that Mr. Biden had the track record to help working-class people organize for higher wages, better retirement benefits and health care.
“It’s not about anything but our best shot at taking power for the working class,” Mr. Fain said on Wednesday after a lengthy speech comparing Mr. Biden’s past pro-union speeches with Mr. Trump’s lack of support and appearances at nonunion facilities. He called Mr. Trump a “scab” — shorthand for someone who declines to support a union.
“This election is about who will stand up with us and who will stand in our way,” Mr. Fain said as many in the crowd got to their feet. “Our endorsement must be earned and Joe Biden has earned it.”
The value of the endorsement, which the U.A.W. put off last year amid concerns about Mr. Biden’s commitment to promoting good jobs in electric-vehicle manufacturing, may be less about persuading members to back Mr. Biden than in motivating them to vote. The union has estimated that only about 30 percent of its members supported Mr. Trump in 2016. But without the union’s formal backing and investments in turnout, Mr. Biden could suffer a drop-off in members who show up to vote in critical swing states like Michigan.
“Elections aren’t about just picking your best friend for the job or the candidate who makes you feel good,” Mr. Fain said. “Elections are about power.”
With Mr. Trump all but locking up the nomination after his performance in New Hampshire’s primary on Tuesday, officials with the Biden campaign said that the race between the two candidates had all but begun.
In his remarks on Wednesday, Mr. Fain, a past vocal critic of Mr. Trump, did not mince words. Mr. Fain called back to the 2008 financial crisis, highlighting Mr. Trump’s past anti-union rhetoric then and as a presidential candidate. Then he recalled Mr. Biden’s comments, as vice president, that the “nation bet on American autoworkers and won.” At this, attendees yelled out obscenities about Mr. Trump. “Love the energy,” Mr. Fain replied.
Mr. Fain, accompanied by a slide show and visual aids, said that Mr. Trump had “said nothing” to support autoworkers during labor disputes as president, “because he doesn’t care about the American worker.” He compared Mr. Trump’s September appearance at a nonunion plant with photos of Mr. Biden taking the picket line, prompting attendees to stand up and chant, “JOE! JOE! JOE!”
Still, Mr. Fain had made the president work for the endorsement.
Mr. Biden appeared at several U.A.W. events to prove his bona fides with the group’s leadership and rank and file. In September, Mr. Biden grabbed a bullhorn and joined striking autoworkers in Michigan, becoming the first sitting president to join a picket line in an extraordinary show of support for workers demanding better wages. When the contract was won, Mr. Biden wore a red T-shirt and appeared before celebrating workers in Illinois.
“I’ve been involved in the U.A.W. longer than you’ve been alive,” the president, then 80, told the boisterous crowd at an event in November, after the union reached an agreement with Ford, General Motors and Stellantis on a contract that included pay increases and reopened a plant in Belvidere, Ill.
At that event, he castigated Mr. Trump for insisting that electric vehicles would lead to the loss of thousands of manufacturing jobs.
“Well, like almost everything else he said, he’s wrong,” Mr. Biden said at the time. “And you have proved him wrong. Instead of lower wages, you won record gains. Instead of fewer jobs, you won a commitment for thousands of more jobs.”
Union officials often say Mr. Biden has been more vocal than any president in decades in backing organized labor. He appeared in a video as Amazon workers in Alabama sought to unionize, warning that “there should be no intimidation, no coercion, no threats, no anti-union propaganda,” and called out Kellogg for its plans to permanently replace striking workers. (The strike was resolved before the company took that step.)
The U.A.W. was early to support Mr. Biden’s green energy policies, but became frustrated by the lack of support for unionized auto-industry jobs in the Inflation Reduction Act, the major climate bill that the president signed in 2022.
It takes fewer workers to assemble an electric vehicle than it does to build one with an internal combustion engine. To make up for those lost assembly jobs, the U.A.W. wants to organize the battery plants and other electric vehicle parts plants that are being built at a rapid pace to take advantage of the generous tax incentives included in Mr. Biden’s climate legislation. They are also pushing to extend union organizing to electric vehicle makers that have long resisted it.
“The E.V. transition is at serious risk of becoming a race to the bottom,” Mr. Fain wrote in an internal memo last May announcing that the union planned to withhold an endorsement of Mr. Biden, at least temporarily. “We want to see national leadership have our back on this before we make any commitments.”
The following month, Mr. Fain expressed frustration that the Biden administration had given Ford a $9 billion government loan to build three electric-vehicle battery plants in Tennessee and Kentucky without any commitment by the company to create high-wage union jobs there.
Mr. Biden’s team redoubled its efforts to engage the union. He tapped Gene Sperling, a longtime Democratic policy hand who is from Michigan, to serve as his liaison to the union and the auto industry. In August, the president’s administration unveiled $12 billion in grants and loans for electric vehicle manufacturing, which would give priority to companies that support well-paying jobs in unionized areas. Mr. Sperling was also in regular contact with senior union officials in the run-up to the strike and during the strike itself.
Mr. Biden also used the National Labor Relations Board, the Transportation Department, the Labor Department, even the Environmental Protection Agency, to ease union organizing through rules attached to government grants and incentives. Even after the U.A.W.’s 46-day strike ended successfully with big wage gains, Mr. Biden embraced the union’s pledge to turn its attention to organizing nonunion automakers like Tesla, Volkswagen and Hyundai.
Mr. Biden’s decision to appear on the picket line in Michigan raised the ire of auto industry executives, according to administration officials, who said that the president was nonetheless determined to make clear where he stood in the labor conflict.
Seeing an opening with the U.A.W.’s rank and file, if not its leadership, Mr. Trump then made a play for the endorsement, campaigning against Mr. Biden’s “ridiculous Green New Deal crusade.” A day after Mr. Biden joined the U.A.W. picket line, Mr. Trump rallied at a nonunion auto parts factory in Michigan, vying for the support of blue-collar workers in the critical swing state.
Mr. Fain had long made it clear his leadership would never endorse the former president.
“I don’t think the man has any bit of care about what our workers stand for, what the working class stands for,” Mr. Fain said in September. “He serves a billionaire class, and that’s what’s wrong with this country.”
Still, the endorsement is politically complicated for Mr. Fain. In addition to the substantial portion of his membership that is likely to favor Mr. Trump, the U.A.W. also includes a vocal liberal bloc that is skeptical of Mr. Biden. Many of the liberal members are graduate students and university researchers who have been critical of the president over his support for Israel during its war in Gaza. The union itself has called for a cease-fire.
At the conference, several U.A.W. members said that they had seen how the war in Gaza had divided their ranks.
“There’s people in these lines that are hurting,” said Daniel Dunbar, 67, a retired autoworker from Flint, Mich. “They have family over there, and they’re afraid for them.”