Teamsters will not endorse Harris or Trump in 2024 presidential election

The International Brotherhood of Teamsters on Wednesday announced it will not formally endorse a candidate in the 2024 presidential election, ending months of speculation about whether the labor union would back Republican Donald Trump or Democrat Kamala Harris.

The union's General Executive Board said in a statement that its member polling showed no majority support for Harris, and no universal support for Trump.

"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 said in the statement.

"We sought commitments from both Trump and Harris not to interfere in critical union campaigns or core Teamsters industries—and to honor our members' right to strike—but were unable to secure those pledges," said O'Brien.

With 1.3 million members, the Teamsters union is one of the largest labor groups in the country. The non-endorsement is a break from the union's decades-long tradition of backing Democratic candidates. But it's not a complete surprise.

O'Brien had signaled in July that the union was open to endorsing Trump when he delivered a speech on the first night of the Republican National Convention.

"As the strongest and most democratic labor union in America, it was vital for our members to drive this endorsement process. Democrats, Republicans, and Independents proudly call our union home, and we have a duty to represent and respect every one of them," O'Brien said.

"We strongly encourage all our members to vote in the upcoming election, and to remain engaged in the political process. But this year, no candidate for President has earned the endorsement of the Teamsters' International Union."

In a national survey of Teamsters members conducted after the Sept. 10 presidential debate, union members overwhelmingly backed Trump over Harris, 58% to 31%, according to results published by the union ahead of its formal endorsement.

The Trump campaign pointed to the poll results in its response to the union's lack of endorsement, writing in a campaign email that the "rank-and-file of the Teamsters Union supports Donald Trump for President."

The most recent results are very different from those of surveys conducted when President Joe Biden was still the Democratic nominee. Before Biden dropped out of the race on July 21, the union's rank-and-file members backed Biden over Trump, 44.3% to 36.3%.

The announcement came just days after union members and leadership met with Harris, who has received endorsements from several other labor unions.

Union leaders also featured prominently at the Democratic National Convention in August, but the Teamsters — and O'Brien — were conspicuously absent. After appearing at the RNC, a spokesperson for the union confirmed to CNBC that O'Brien had not received an invitation to speak at the Democratic convention.

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

This is a developing story, please check back for updates.