For the first time in nearly three decades, the International Brotherhood of Teamsters won’t endorse a candidate in the presidential race — a blow to the Democratic Party, which has reliably received the union’s approval for years.

The Teamsters confirmed the decision not to endorse Wednesday, as the union’s executive board met in Washington to consider an endorsement.

The non-endorsement comes two days after union leaders and members met privately with Vice President Kamala Harris and she laid out her case for an endorsement,underscoring the current administration’s many achievements for unions.

“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,” said Teamsters president Sean O’Brien in a statement. The union had “sought commitments from both Trump and Harris” specifically about their union campaigns, core industries and right to strike, but “were unable to secure those pledges,” he added.

Lauren Hitt, a spokesperson for the Harris campaign, said in a statement that the “Vice President’s strong union record is why Teamsters locals across the country have already endorsed her — alongside the overwhelming majority of organized labor.”

Hitt also referenced a recent comment Trump made about firing striking workers in a conversation with Elon Musk, adding that Harris “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.”

The Trump campaign did not immediately respond to a request for comment.

The decision arrives as the powerful transportation workers union, with its 1.3 million members, has forged inroads with the GOP. O’Brien addressed the Republican National Convention in July, becoming the first labor leader to do so and sending shock waves through Democratic circles.

The Teamsters have a strong presence in battleground states and could play an outsize role in the election.

The non-endorsement underscores a major division within the Teamsters, as well as other American unions with diverse membership. The results of two surveys of Teamsters membership released Wednesday by the Teamsters showed rank-and-file members strongly favoring a Trump endorsement over Harris — while several powerful Teamsters local chapters have broken with his leadership to urge members to vote for Harris.

“This election is likely to come down to a handful of votes in the ‘blue wall’ states,” said Steve Rosenthal, a Democratic political strategist in the labor movement for decades. “The Teamsters have a significant number of members in each of those states. … Their endorsement coupled with a program aimed at mobilizing their members could be a deciding factor.”

No endorsement “likely means the difference between their members voting 50 percent for Harris versus close to 60 percent,” he said, adding that “in a close race, that could be significant.”

Yet, the absence of an endorsement is unlikely to have a noticeable impact on Harris’s campaign financing given the substantial amount of donations her campaign has received, Democratic strategists say. The Harris campaign is flush with cash, raising $615 million in the first six weeks after she joined the race. The Teamsters have donated more than $800,000 so far this election cycle, with more than 92 percent going to Democratic PACs, according to OpenSecrets, a nonprofit that tracks campaign finance.

This election cycle, many unions endorsed President Joe Biden much earlier than is typical, reflecting his administration’s efforts to champion labor. When Biden dropped out of the race in July, those unions swiftly rallied behind Harris, citing her role in the administration’s accomplishments for labor.

The Teamsters union typically waits to endorse until after both political conventions have taken place, and this year, O’Brien said the union would not stray from that tradition.

That decision has sparked an internal rift within the union.

“We’ve made a huge mistake,” John Palmer, a Teamsters executive board member and vice president at large who has been openly critical of the union’s burgeoning relationship with Republican nominee Donald Trump, said this week. “We’ve lost out on an opportunity to try to get our members to understand why they shouldn’t be voting for [Trump].”

After Monday’s meeting with Harris, O’Brien praised “her willingness to meet with rank-and-file Teamsters face-to-face,” and said the union was weighing its endorsement.

The Teamsters have endorsed the Democratic ticket in every presidential election since 1996, when they did not endorse a candidate. The union had closer ties to the GOP decades ago, endorsing Richard M. Nixon, Ronald Reagan and George H.W. Bush.

Teamsters leadership had taken a different approach to this presidential election, meeting with several candidates, including Biden, Robert F. Kennedy Jr., and academic and activist Cornel West. O’Brien met privately with Trump at his Mar-a-Lago estate in January and held a roundtable with the former president at the union’s headquarters. The union also donated $45,000 to both the Democratic National Convention and Republican National Convention, the latter marking the first major contribution to the GOP in years.

The budding relationship between the Teamsters and the GOP drew an uproar from progressive Teamsters, highlighting political divisions within the union’s membership, as well as Democrats in Washington. But O’Brien had explained the union’s strategy as an effort to carefully assess its options, saying that his members’ votes “will not be taken for granted.”

The indignation culminated with O’Brien’s prime-time address at the RNC, where he both praised Trump days after an assassination attempt — calling him “one tough SOB” — and railed against corporate greed, pledging to work with anyone who would support union priorities. Critics of O’Brien said his RNC address gave conservative members tacit approval to vote for Trump. Supporters say O’Brien’s efforts could move the GOP, which has been flirting with right-wing populist ideas, to the left on labor issues.

O’Brien had also requested to speak at the DNC but did not receive an invitation, according to the union. Democrats invited rank-and-file Teamsters whose pensions were saved by the Biden-Harris administration to speak on the convention stage.

Since then, the Teamsters National Black Caucus, as well as six union locals, went ahead and endorsed Harris anyway, urging their members to vote for her.

Local Teamsters union leaders have sent scathing letters to O’Brien, demanding a Harris endorsement: “I am completely disappointed and appalled at your decision to court one of the most anti-union, anti-worker politicians in history, Donald Trump,” Josh Zivalich, president of Teamsters Local 769 in Miami, wrote to O’Brien on Aug. 14.

Some labor experts say O’Brien has adopted a more bipartisan approach under pressure to consider the membership’s diverse political leanings. He won the union’s top office in 2021 after running as a reform candidate who promised more member involvement in union decision-making. O’Brien is also aware that many rank-and-file Teamsters are Trump supporters, experts say.

The Biden-Harris administration is widely viewed by historians as one of the most pro-union in modern U.S. history. The administration appointed a pro-labor leader to the National Labor Relations Board and has enacted three major spending bills with pro-union provisions. Plus, in a major victory for the Teamsters, the White House secured a pension bailout that restored retirement accounts for about 600,000 union members.

Trump has called himself “pro-worker.” And his selection of Sen. JD Vance as running mate reflects mounting pressure within the Republican Party to embrace populist right-wing politics intended to capture working-class votes. Still, as president, Trump supported a labor agenda that severely restricted union power, including installing NLRB appointees whose policies and rulings made it harder for workers to join unions.

The Teamsters released the results of an electronic poll of Teamsters members, which showed 59.6 percent supporting a Trump endorsement compared to 34 percent supporting a Harris endorsement.

The Teamsters also conducted a separate poll of Teamsters members, by phone, which they reported also gave Trump a similar lead.

Both polls were conducted by a third-party union polling service, according to the Teamsters, which did not provide information on the polling size or methodology.