The International Brotherhood of Teamsters, one of the most prominent and influential unions in the country, said Wednesday it will not endorse any presidential candidate this year — a blow for both candidates.

The 1.3-million-member union has historically thrown its weight around in presidential cycles and endorsed Democratic presidential candidates in recent cycles, with 1988 being the last time it supported a Republican, then-Vice President George H. W. Bush. However, hours before the union was set to announce its highly coveted endorsement on Wednesday, the Teamsters released polling of union members showing a nearly two-to-one preference for former President Donald Trump over Vice President Kamala Harris.

“The Teamsters thank all candidates for meeting with members face-to-face during our unprecedented roundtables. Unfortunately, neither major candidate was able to make serious commitments to our union to ensure the interests of working people are always put before Big Business,” Teamsters President Sean O’Brien, who took on the role in 2022, said in a statement.

“Democrats, Republicans, and Independents proudly call our union home, and we have a duty to represent and respect every one of them. We strongly encourage all our members to vote in the upcoming election, and to remain engaged in the political process,” he added. “But this year, no candidate for President has earned the endorsement of the Teamsters’ International Union.”

Blue-collar union workers have been a mainstay of Democratic support for several cycles, but Trump has made inroads with voters without a college degree, a key demographic that helped eat away at Democrats’ union advantage.

Most of the country’s largest unions, including the AFL-CIO and United Auto Workers union, endorsed President Joe Biden before he dropped out, and that support was reiterated for Harris after she took over as Democrats’ nominee. The Teamsters, however, stayed out of the fray.

The union sought to hold meetings with Biden and Trump, and it met with Harris earlier this week before making any decision.

O’Brien ruffled Democrats’ feathers when he addressed the Republican National Convention earlier this summer — a move that was fiercely criticized by some of his counterparts — and praised Trump, though he accused the former president of backing “economic terrorism” when he expressed support for firing striking workers, which is illegal under federal law.

“I want to be clear. At the end of the day, the Teamsters are not interested if you have a ‘D,’ ‘R,’ or an ‘I’ next to your name,” O’Brien said on the stage in Milwaukee. “We want to know one thing: ‘What are you doing to help American workers?’ As a negotiator, I know that no window or door should ever be permanently shut.”

The union’s decision Wednesday marks a blow for both candidates.

Trump had wooed the union, inviting O’Brien to Mar-a-Lago and culminating in O’Brien’s primetime RNC speech.

Harris, meanwhile, has sought to shore up support among non-college educated voters, particularly in the industrial Midwest, a key region in this year’s election where the Teamsters hold sway. The Biden administration has also repeatedly touted its pro-union bona fides, and Biden himself became the first sitting president in history to walk a picket line. However, unions were peeved at the role the administration played in averting a rail strike in late 2022.

After the union’s announcement, the Harris campaign said she has “stood strong with organized labor for her entire career.”

“As the Vice President told the Teamsters on Monday, when she is elected president, she will look out for the Teamsters rank-and-file no matter what — because they always have been and always will be the people she fights for,” Harris campaign spokesperson Lauren Hitt said in a statement.

Trump’s campaign said while the Teamsters didn’t endorse a candidate “they want President Trump back in the White House.”

“These hardworking men and women are the backbone of America and President Trump will strongly stand up for them when he’s back in the White House,” Trump campaign press secretary Karoline Leavitt said in a statement.

Later, Trump himself called the Teamsters decision to not endorse either candidate an “honor.”

“It’s a great honor. They’re not going to endorse the Democrats. That’s a big thing. And this is the first time in I guess, fifty, sixty, years, that that’s happened. Democrats automatically have the Teamsters,” Trump said.

This decision by the Teamsters isn’t just a blow to the Harris campaign, which has the support of other powerful labor unions, it’s also a blow to Biden, the self-declared “most pro-union president in history.”

The Teamsters backed Biden in 2020 and as president he put union labor at the heart of his economic policy, evident by his constant refrain that “the middle class built this country and unions built the middle class.”

And Biden delivered. He essentially saved their pensions two years ago, providing $36 billion to shore up union pension plans preventing drastic cuts to the retirement income of roughly 350,000 Teamster workers. Without this assistance, Teamster members could have seen their benefits slashed by 60% in coming years.

Asked Wednesday if the president was surprised by their decision not to endorse a candidate, given everything the president has done, White House press secretary Karine Jean-Pierre responded, “I’m not going to get into endorsements.”

“Let’s not forget, he’s brought American manufacturing back home, creating close to 800,000 manufacturing jobs. And by creating the first Made in America office. And so these are things that he’s incredibly proud of,” she said.

The internal polling the Teamsters released earlier Wednesday showed that straw polls of members supported Biden over Trump by an 8-point margin, 44-36%. The methodology of this internal survey is not known.

In explaining its decision, the Teamsters union cited the lack of “majority support” for Harris and “no universal support among the membership” for Trump. However, it did note that Harris had pledged to sign pro-union federal legislation and that Trump would not commit to vetoing national “right to work” legislation, which would allow workers to opt in or out of unions in unionized workplaces — laws that are enacted in several states that national groups like the Teamsters say weakens collective bargaining power.

Still, the Teamsters’ National Black Caucus and several Teamsters’ local chapters got out in front of the national organization and endorsed Harris on their own in recent weeks, including Local 623 in Philadelphia, which pointed to work done during the Biden administration, Harris’ pledge to “expand union rights” and challenge “any anti-union ‘right to work’ legislation,” and the “threat posed by Donald Trump.”

Teamsters National Black Caucus Chairman James Curbeam said he believes this lack of endorsement will galvanize more local union leaders to organize and rally around Harris.

A Teamsters union endorsement could have given Harris a boost in key battleground states — including Michigan, Nevada and Pennsylvania.

“It’s a tacit endorsement of Trump,” said John Palmer, a Teamsters executive board member, who added that this lack of endorsement “encourages right-leaning union workers to support Trump.”