Teamsters boss endorses Sen Markwayne Mullin for DHS after Senate clash

Nearly two and a half years after nearly coming to blows during a viral Senate hearing, Teamsters Chairman Sean O’Brien praised Sen. Markwayne Mullin, R-Okla., Thursday after President Donald Trump nominated him to head the Department of Homeland Security.

“If anyone is ready to stand up to protect America, it’s Markwayne Mullin,” O’Brien said in a statement.

The endorsement marked a landmark turning point for the two men, who clashed publicly in November 2023 during a heated Senate Health, Education, Labor and Pensions Committee hearing that seemed on the verge of a physical altercation.

During the exchange, Mullin, a former mixed martial arts fighter, referenced a social media post in which O’Brien said he could take the senator “anytime” or “anywhere.”

Teamsters boss Sean O’Brien is endorsing Sen. Markwayne Mullin for DHS chief, two years after their viral Senate hearing nearly turned into a physical fight. (Bill Clark/CQ-Roll Call, Inc via Getty Images; Kevin Dietsch/Getty Images)

“Sir, this is the time, this is the place. You want to talk, we can be two consenting adults, and we can end it here,” Mullin said during the hearing.

Mullin then stood up and appeared ready to approach O’Brien before Sen. Bernie Sanders, then the committee’s chairman, intervened.

“Stop it, wait, no, no, sit down,” Sanders said. “You are a United States senator. Sit down.”

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Senators Bernie Sanders and Markwayne Mullin and Teamsters President O’Brien (Reuters/Getty Images)

The confrontation continued verbally for several minutes, with Mullin calling O’Brien a “thug” and O’Brien calling the senator “disrespectful,” before Sanders struck with his gavel and moved the hearing forward.

The two men had also argued months earlier over O’Brien’s salary compared to that of union members, forcing Sanders to intervene at that hearing as well.

O’Brien’s statement Thursday stood in stark contrast to the combative exchanges that once defined their relationship.

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The statement comes as Mullin was named to lead DHS following what Trump described as a turbulent tenure under current Secretary Kristi Noem, who will be reassigned to serve as special envoy for the Americas Shield, a new security initiative focused on the Western Hemisphere.

The clash between the two men in November 2023 follows months of escalating tensions, including a public protest earlier that year when Mullin accepted O’Brien’s social media challenge “anywhere, anytime” and proposed a charity mixed martial arts fight in Tulsa. But tensions appeared to ease in 2024 after Trump helped broker a truce between the two men.

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Sen. Markwayne Mullins, R-Okla., speaking to reporters shortly after his nomination to lead DHS. (Anna Moneymaker/Getty Images)

Mullin later recounted on “Fox Across America with Jimmy Failla” that Trump contacted O’Brien early on as Teamster members were leaning more and more Republican.

Mullin said O’Brien told him that many of his members supported Trump and that the union leader felt compelled to think about the political position of “my brothers.”

Andrew Mark Miller and Houston Keene of Fox News contributed to this report.

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