'Stand your butt up': Senator challenges union boss to fist fight during hearing

A Senate committee hearing was thrown into chaos after a Republican senator stood up and threatened to fight a labor leader, forcing Sen. Bernie Sanders to call for calm.

"Sir this is a time, this is a place, you want to run your mouth we can be two consenting adults and we can finish it here," Sen. Markwayne Mullin told Teamster President Sean O'Brien during a Senate Health Committee session today.

The GOP representative and former MMA fighter made the remarks after reading a post on X (formerly Twitter) in which O'Brien boasted that the senator knew where he could find him "any time" or "any place."

"Ok, that's fine, perfect," O'Brien replied.

READ MORE: Bernie Sanders warns millions of Americans have ‘no retirement savings’

"You want to do it now?" Mullin asked.

O’Brien then said he would “love to do it right now”, prompting Mullin to respond, "Well, stand your butt up then."

"You stand your butt up, big guy," O'Brien fired back.

Mullin then stood up, which brought a rebuke from Sanders, the committee's chairman.

"Stop it, hold it, no, no, sit down," Sanders shouted, "You're a United States senator. Sit down."

Mullin and O'Brien both asked permission from Sanders to respond to each other after the senator returned to his seat, but the request was denied.

The pair proceeded to exchange barbs for several minutes.

"You challenged me to a cage match acting like a 12-year-old," said O'Brien, after Mullin accused the union boss of being "quiet" when challenged.

An exasperated Sanders finally had to shout over the Oklahoma senator. "Excuse me, hold it. Sen. Mullin, I have the mic."

"We're not here to talk about physical abuse," Sanders said.

Mullin then pointed at O'Brien, branding him a "thug", with O'Brien calling him "disrespectful" in response.

The two men both said he didn’t respect each other, which brought yet another interjection from Sanders.

"Hold it," said Sanders as he banged his gavel. "This is a hearing to discuss economic issues…we're not here to talk about fights or anything else."

Despite Sanders’ pleas for order, the arguing continued until the hearing moved on others lines of questioning from panel members.

This isn’t the first time O'Brien and Mullin have locked horns. In March, the pair fired back at each other in a fraught Senate Health, Education, Labor and Pensions Committee hearing over O'Brien's salary compared to members of his union.

Sen. Sanders had to intervene and struggled to contain them on that occasion too.

Mullin and O’Brien ignored Sanders and continued bickering. At one point Mullin told O’Brien, "Sir, you need to shut your mouth because you don't know what you're talking about."

To which O’Brien responded: "You're going to tell me to shut my mouth?" before poking fun at Mullin's opening statement in which the lawmaker said he wasn’t "afraid" of a physical altercation.

After the hearing today, Mullin continued to criticize O'Brien as well as Sanders for not addressing what he described as O'Brien's "lack of decorum" during the session.

"The behavior we saw today was typical of how union bosses, many of whom have never created a single job, use intimidation tactics to pressure employees into joining unions which some workers may deem to be against their interests," Mullin said in a statement to Fox Digital.

"I find it unacceptable that Chairman Bernie Sanders did nothing to address the lack of decorum from the witness panel."

"As a business owner, I’ve seen firsthand how unions have tried to intimidate employees who receive better pay and benefits than unionized workers. Union bosses conveniently ignore the fact that defending the rights of all workers means defending those who do not want to join a union.

“If union bosses, like those we saw today, reject common sense measures like private ballots and right-to-work, I have a major problem with that," he said.

"This should be simple: American workers and their families should have the freedom to decide what to do with their hard-earned income. As the Senator from Oklahoma, a booming right-to-work state, I will always support workers’ free ability to choose for themselves whether or not to join a union," he added.

The Teamsters union has been approached for comment.