Fresh off some historic wins for the labor movement, United Auto Workers President Shawn Fain could be the man who makes the biggest difference for President Biden in key Midwestern swing states in the fall.

The union leader has soared to prominence over the past year by leading the UAW to some of its most significant gains in decades. He’s a captivating speaker who commands the attention and trust of many workers at a time when Biden is struggling to connect with voters because of higher prices and Israel’s destructive war in Gaza.

“We need to know who is going to stand up with us! And this choice is clear. Joe Biden bet on the American worker, while Donald Trump blamed the American worker!� Fain said in a rousing speech endorsing Biden in January.

Fain’s star power, along with the endorsement and the union’s long-standing voter turnout efforts for Democrats, will be crucial in Michigan, Wisconsin, Pennsylvania and other industrial states that could hinge on a few thousand votes, labor and political experts say.

“Shawn Fain has done an extraordinary job of restoring the union to where it belongs — not just to the front of the labor movement but to the front of progressive fights,� said Steve Rosenthal, the former political director of the AFL-CIO union federation. “He will have enormous credibility.�

The key in swing states will be turning out working-class voters who might otherwise stay home, a task for which Fain can have an impact “maybe beyond any other person,� said Larry Cohen, former president of the Communications Workers of America union and a Democratic operative working on voter turnout.

Asked about politics in an interview, Fain said he is focused on his UAW work, including unionizing a string of Southern auto factories and bargaining a new contract for Daimler Truck workers, who won hefty raises in a deal announced late Friday. But he pledged to help Biden, saying that the labor movement’s goals depend on electing supportive politicians.

“I’m running a union right now, and our number one objective is organizing and winning good contracts,� he said. “But obviously, you know, politics is a part of all this. And where I can support the president, I’m going to support him.�

Biden, he added, is aligned with the union on the biggest issues facing the working class, including wages, health care and retirement security. “And that’s why we endorsed him versus Donald Trump, who represents the billionaire class and corporate class, and couldn’t care less about workers,� said Fain, who got his start as an electrician for Chrysler.

That message resonates with many autoworkers. Bill Bagwell, a longtime UAW member at a General Motors facility in Michigan, said GM, Ford and Stellantis workers are happy with the large raises they received after last year’s strikes, which may make them more fired up for election season.

“You have members who may have been on the fence last time and maybe voted Donald Trump who now have a much better relationship with their union and may be more willing to do what the union is asking them to do,� Bagwell said.

Backing Biden while attempting to organize big factories in red states is forcing Fain and the UAW into a difficult balancing act. The union’s endorsement of Biden rankled some Volkswagen workers in Chattanooga, Tenn., in the weeks before the factory voted to join the UAW, workers said. In the run-up to the vote, UAW organizers took pains to tell the workforce that they were free to support whichever politician they like. Supporting Biden in a full-throated manner could be tougher as the UAW expands its push into more factories in the South, including Alabama, Georgia and South Carolina.

Biden campaign aides say they plan to work regularly with Fain over the coming months, though they did not provide specifics. Fain was a guest of Biden’s at the State of the Union last month and received a shout-out during the speech, but he has not appeared at campaign events.

“We’re proud to have earned UAW’s support, and we join them in their mission to hold corporations accountable, strengthen our unions and grow our middle class,� Biden campaign manager Julie Chavez Rodriguez said in a statement.

Campaign officials have celebrated and amplified Fain’s commentary in recent months, hoping the increasingly popular figure will help the president burnish his bona fides with blue-collar voters. While labor leaders overwhelmingly support Biden, some rank-and-file members have backed Donald Trump in past elections.

Biden regularly casts his presidency as the most pro-union in American history, and aides say he plans to lean on organized labor to spread his message about the growing economy. He has made multiple visits to union meetings in recent months, including an International Brotherhood of Electrical Workers conference and a United Steelworkers event.

“Unions are more popular today than they’ve ever been in a long, long time, not because of Joe Biden supporting them — because of you,� Biden said Thursday after receiving the endorsement from the North America’s Building Trades Unions. “You always step up. You step into the breach. You get things done.�

Some Democratic strategists say Fain could even help Biden with discontent throughout the party over the administration’s handling of the Israel-Gaza war, a special cause for concern for Democrats in Michigan, which has a large Arab American population. Both Fain and the UAW called for a cease-fire early in the conflict, after it boiled up as an issue among some members of the union, which represents not just autoworkers but graduate students employed by universities. Fain said the union is still pressing Biden on Gaza, but he stressed that Trump would be worse for the conflict and for the labor movement.

“One of two people is going to be president of the United States in this upcoming election. And obviously the other candidate would be a complete disaster, not just for labor, but for the situation in Gaza,� Fain said. “We talk to the president quite often and his staff about our concerns in Gaza and that there needs to be more action. And we’re going to continue to do that.�

Fain and Biden have been engaged in a complicated dance since the UAW president’s election a year ago. Officials in the White House, who did not know Fain well at the time, were forced to pay attention to him as the new UAW leader publicly slammed the Biden administration over policy disagreements and pointedly withheld the union’s endorsement of the Democratic president early on.

“Our endorsements are going to be earned. They’re not going to be freely given, as they have been in the past,� Fain told The Washington Post last year. Among his complaints was the administration’s use of billions of taxpayer dollars to subsidize battery and electric-vehicle factories without requiring strong worker pay.

Biden launched a charm offensive, inviting Fain to the Oval Office to discuss the EV transition, repeatedly speaking with him by phone and, in a first for a sitting president, joining a UAW picket line as workers were striking against Detroit’s Big Three automakers last year. Biden also pushed Jeep-maker Stellantis to reopen a shuttered factory in Illinois, a deal that helped resolve the strikes.

“If our endorsements must be earned, Joe Biden has earned it,� Fain declared at an autoworker conference in January.

The UAW has long played a role in turning out voters, reminding its members to vote and making sure they know how to check their registration status and access absentee ballots. Union members also knock on doors handing out information on candidates.

“I see president Fain playing that role of encouraging members to vote for President Biden, but his style is to let the membership decide,� said Scott Houldieson, a friend of Fain and a UAW worker at a Ford factory in Chicago. “He’ll lay the facts out there for the members.�

Jeff Timmer, former executive director of the Michigan Republican Party and now senior adviser to the anti-Trump Lincoln Project, said he thinks Fain will try to maintain an “independent broker status.�

“I don’t think it would be fair to characterize him as a Democratic surrogate,� he said. “Certainly the Democratic Party is the closest ally, but it’s UAW first, Democratic Party second.�

Fain said one of his main messages is convincing workers that voting matters.

“It’s why we’re in the predicament we’re in now — where three American families have as much wealth as half of Americans — is because half of America doesn’t even vote, because they’re fed up,� he said in the interview. “They feel like it doesn’t matter. And we’ve got to make people understand that it does matter. And the only way you change that is by voting. Because no matter how much money the wealthy have and how much money they inject into politics, working-class people have the votes.�

While Fain has been a strong validator for Biden, he may play a more critical role by undercutting Trump’s appeal with rank-and-file members, said Harley Shaiken, a labor professor at the University of California at Berkeley.

Trump has lashed out at Fain, calling him a “weapon of mass destruction� on autoworkers. Trump spokeswoman Karoline Leavitt said by email that the former president “delivered� for union workers when he was in the White House and will “put them first again when he is reelected.�

During his speech endorsing Biden, Fain launched into a broadside against the former president, saying Trump did not speak out during a 2019 autoworkers strike and “doesn’t care about workers.� Trump, he said, was a “scab.�