But when Donald Trump gave his hugely divisive acceptance speech three days later, he seemed to forget he was supposed to act lovey-dovey toward labor unions. The former president essentially kicked the United Auto Workers (UAW) in the teeth, and the UAW fired back by calling Trump the “mascot and lapdog” of billionaires.

Trump then directed his fire at the UAW’s president, Shawn Fain, saying he “should be fired immediately”, even though Fain’s stature and popularity have soared across the US because he led last fall’s victorious strike against Detroit’s automakers.

Fain struck back the next day, saying: “Last night, Donald Trump once again attacked our union on a national stage.” He said Trump “stands for everything we stand against”. Fain asked why, when General Motors closed its huge plant in Lordstown, Ohio, in 2019, “when Trump was president and our members were on strike for 40 days, he said nothing and did nothing”.

Fain didn’t stop there, saying: “Trump doesn’t want to protect American auto workers. He wants to pad the pockets of the ludicrously wealthy auto executives. He wants autoworkers to shut up and take scraps, not stand up and fight for more.”

Fain no doubt remembers Trump’s nasty history of insulting and attacking labor leaders. In 2018, the then president tweeted out an attack against Richard Trumka, the late, highly regarded secretary-general of the AFL-CIO, the nation’s main labor federation. Trump, whose administration took a myriad of anti-worker actions, suggested that Trumka was sabotaging US workers. Trump even once blamed Dave Green, the president of the UAW local in Lordstown, for the closure of the huge Lordstown plant that Green fought so hard to save. 

“America’s autoworkers aren’t the problem. Our union isn’t the problem,” Fain said on Friday. “Corporate greed and the billionaires’ hero, mascot and lapdog, Donald Trump, are the problem. Don’t get played by this scab billionaire.”

Trump’s rant against the UAW indicated that O’Brien’s maneuver was failing. O’Brien had hoped that by speaking at the convention and giving Republicans some pro-labor credibility, the Republicans and Trump would return the favor by making nice to unions.

When Trump gave his hugely divisive acceptance speech, he seemed to forget he was supposed to act lovey-dovey toward labor unions

But then Trump proceeded to attack the UAW, partly out of pique that it hasn’t endorsed him. During the UAW’s big strike last September, Trump spoke to some workers and supporters in Michigan and said the UAW’s “leadership should endorse me, and I will not say a bad thing about them again”. In other words, endorse me, or I’ll slam you and slime you.

In his acceptance speech, Trump said: “Every single auto worker, union and non-union, should be voting for Donald Trump because we’re going to bring back car manufacturing.” Unfortunately for Trump, many auto workers remember that in 2017, Trump bemoaned Ohio’s loss of manufacturing jobs and assured a crowd in Youngstown: “They’re all coming back ... We’re going to get those jobs coming back.” But Trump’s promise was empty; those jobs didn’t come back under his administration.

Unlike the Teamsters, most major labor unions endorsed Joe Biden before he withdrew from the race, with many unions saying he was the most pro-union president in history. In a CNN interview after his speech, O’Brien agreed, saying: “Biden is definitely the most pro-labor president we’ve ever had.”

O’Brien was trying to both court and bring a big shift in a party that has long been extremely hostile toward unions. O’Brien praised several Republicans who had taken some baby steps to show support of unions; he noted that Missouri senator Josh Hawley had walked a Teamster picket line.

O’Brien failed to mention that Biden was the first sitting US president ever to join a picket line. He also failed to mention that Hawley scored 0% in 2023 on the AFL-CIO’s legislative scorecard or that Senator JD Vance, Trump’s supposedly pro-worker running mate, also scored zero.

O’Brien’s gamble backfired. Many labor leaders condemned him for undermining the Democrats and helping Trump. John Palmer, a Teamsters vice-president, was so angry at O’Brien for playing footsie with Trump that he announced he would run against O’Brien for the Teamsters’ presidency in 2026.

The Teamsters hierarchy defended O’Brien’s appearance by insisting he wanted both major parties to hear pro-union, pro-worker messages and shouldn’t be beholden to one party. To be sure, O’Brien hoped to move Trump toward labor, but he seemed to forget that Trump is dyed-in-the-wool anti-union. Last year, in a “message to America’s auto workers”, Trump said: “You should not pay your dues” and the UAW “was selling you to hell”. Trump once undercut unions by suggesting that midwestern automakers move their plants to the south to lower their wages. Trump’s appointees to the US supreme court and National Labor Relations Board issued one anti-worker, anti-union decision after another.

Many workers, indeed many union members, have embraced Trump because he tells them he that feels their resentments, hears their grievances. Trump has responded to those grievances by bashing immigrants, China and elites. But such bashing has done next to nothing to truly help workers.

The US’s workers need leaders who push to lift their wages, increase worker safety, make childcare more affordable and fight to make unions stronger. Trump is in no way such a leader. As president, he did nothing to raise the minimum wage or make childcare more affordable. He weakened safety protections for many workers. His administration moved in dozens of ways to weaken labor unions.

It’s time that US workers get wise to the fact Trump is not their friend.

[Steven Greenhouse, a senior fellow at the Century Foundation, is an American labor and workplace journalist and writer.]