The United Auto Workers president, Shawn Fain, is telling President Trump to stay out of the union’s strike, saying after reports surfaced that the former president plans to hold an event in Michigan featuring UAW members that he doesn’t know “what it is like to live paycheck to paycheck.”

On Monday, the New York Times reported that Mr. Trump was planning to visit a UAW picket line in an effort to distract from the second Republican presidential primary debate on September 27.

On Tuesday, Mr. Fain made it clear in a statement that Mr. Trump wouldn’t be welcome, saying, “Every fiber of our union is being poured into fighting the billionaire class and an economy that enriches people like Donald Trump at the expense of workers.”

“We can’t keep electing billionaires and millionaires that don’t have any understanding of what it is like to live paycheck to paycheck and struggle to get by and expecting them to solve the problems of the working class,” he said.

Mr. Fain’s statement is an escalation of a growing battle with Mr. Trump, as the former president attempts to align himself with striking union members. Mr. Trump has called on union members to oust Mr. Fain from his position within the union, arguing that Mr. Fain isn’t doing a good job as president and telling union members to vote for him in 2024.

In Mr. Trump’s opinion, if members vote for him, they will become “VICTORIOUS and RICH,” and if the union endorses President Biden as it did in 2020, they will be “JOBLESS and PENNILESS.”

Mr. Trump’s tactic in trying to garner support among the union members is to say that union leadership is selling its members “down the ‘drain’” and telling the news outlet More Perfect Union that “there’s no such thing as a ‘fair transition’ to all electric cars,” calling any move to EVs a “transition to Hell” for union members.

Mr. Trump’s narrative conflicts with the line that the union is drawing on the issue. The union is demanding that employees who work at electric vehicle plants — employees who have been deliberately excluded from the union’s collective bargaining agreements — be included in the contracts going forward.

“We believe in a green economy,” Mr. Fain told CBS. “But this transition has to be a just transition, and a just transition means, if our tax dollars are going to finance this transition, then labor can’t be left behind.”

While the tension between the UAW and Mr. Biden’s administration over electric vehicles has made headlines, dozens of America’s biggest sustainability groups have come out in support of the union’s demands, signing a letter to the Big Three executives.

“We, and millions of Americans,” the letter reads, “want what UAW is bargaining for: family-sustaining, community-supporting, union jobs in a green energy economy; one that allows us all to make a living on a living planet.”

Mr. Trump’s campaign against Mr. Fain will likely be an uphill struggle because Mr. Fain is the first popularly elected UAW president in the union’s history.

Despite Mr. Fain’s apparent disapproval of Mr. Trump, he continues to withhold the union’s 2024 presidential endorsement from Mr. Biden, who came out in support of the striking members last week. Mr. Fain has demanded “actions, not words” to win the endorsement.

In response to reports that Mr. Trump plans to visit the picket line at the end of this month, some Democrats have implored Mr. Biden to visit first to reinforce the party’s more labor-friendly stance.

“I know the UAW family would love the most powerful person in the world — the president of the United States — to come and hold a sign in solidarity with them,” Congresswoman Rashida Tlaib told the Washington Post. “But I hope he does it in a way where he actually sits down and has a roundtable with some key people, and really listens to how hard it’s been.”