Washington DC - The president of the International Brotherhood of Teamsters recently shared why he still hasn't issued an endorsement for either Kamala Harris or Donald Trump in the 2024 presidential race.

In a recent interview with CBS News, President Sean O'Brien explained that while the union has in the past endorsed a candidate following both party's national convention, and typically supports the Democrat, this year things are different.

"This time, under our leadership, we brought every single candidate to the table in front of our rank and file members and our general executive board, and we're waiting on Vice President Harris to commit to come meet with us," O'Brien explained.

In July, O'Brien spoke at the Republican Convention in Milwaukee, the first member to do so in the union's 121-year history.

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His appearance drew backlash from some, who accused him of trying to cozy up to GOP lawmakers, despite their arguably anti-union agenda.

But O'Brien insisted in his interview that the speech "wasn't an endorsement," and revealed that he also asked the Democratic Party to let him speak at their convention, but they ignored the request.

"Half of our members are Republicans, half of our members are Democrats. So we have to serve all of our membership equally," O'Brien argued.

"This is our opportunity to ask [Harris] about Teamster-specific issues and also labor issues. So until we have that meeting... we will wait to make that determination," he added.

The International Brotherhood of Teamsters is one of 10 of the largest labor unions in the country and of that group, they are the only one that has not endorsed Harris for president. The union's National Black Caucus endorsed Harris early last month.

While O'Brien – who was appointed president in 2022 – has been apprehensive about throwing support behind Harris, he has been openly critical of Trump who has himself tried desperately to win the support of workers and unions throughout the race with very little luck.

O'Brien's willingness to flirt with the former president has caused concerns with members, as he has orchestrated private meetings with Trump this year and was behind the union reportedly contributing $45,000 to the Republican Convention fund, which was its first time donating to the party in decades.

Teamsters Vice President at large John Palmer recently launched a campaign to challenge O'Brien for his position, arguing that his RNC appearance was him "kissing the ring of a man that scabbed a picket line."