A US lawmaker who is a former mixed martial arts fighter challenged a witness to a physical fight in the middle of a hearing.

Republican Senator Markwayne Mullin of Oklahoma nearly exchanged blows with the president of the Teamsters union during the Senate Health, Education, Labor and Pensions Committee meeting on Tuesday.

Mullin read International Brotherhood of Teamsters General President Sean O’Brien’s posts on X (formerly Twitter) aloud, in which the union head called him a ‘clown’ and a ‘fraud’ who ‘pretends he’s self-made’.

The senator continued to read from O’Brien’s post: ‘Quit the tough guy act in the Senate hearings. You know where to find me, any time, any place, cowboy.’

‘Sir, this is a time, this is a place,’ Mullin told O’Brien from the dias. ‘You want to run your mouth, we can be two consenting adults, we can finish it here.’

Republican Senator Markwayne Mullin (middle) stands up and challenges a union president to a fight during a committee hearing (Picture: Twitter)

O’Brien replied: ‘OK, that’s fine. Perfect.’

Mullin, 46, then formalized the challenge.

‘You want to do it now?’ the senator said.

After O’Brien said he would ‘love to do it right now’, Mullin said, ‘Stand your butt up then.’

O’Brien shot back: ‘You stand your butt up.’

Mullin got up from his chair and appeared ready to take on O’Brien, who also moved his chair, when committee Chair Bernie Sanders intervened.

‘Hold it. No, no, no, sit down. Sit down!’ Sanders shouted while banging his gavel. ‘You’re a United State senator, sit down.’

Mullin went on to challenge O’Brien to a real fight with proceeds for charity, but Sanders objected.

‘If you have questions on any economic issues, anything that was said, go for it,’ the chair said. ‘We’re not here to talk about physical abuse.’

Sanders had initiated the hearing for unions to share how they are improving the quality of life for American working families.

After the hearing, Mullin did not take back his actions.

‘You don’t call me out and say “anytime, anyplace,” and then not back it up what you said,’ Mullin said. ‘I answered his call. Period.’

It was a testy day for other senators besides Mullin. In the morning, ousted House Speaker Kevin McCarthy elbowed and shoved fellow Republican Senator Tim Burchett, according to NPR congressional correspondent Claudia Grisales. Burchett was one of eight GOP members who voted McCarthy out of leadership in

Senator Markwayne Mullin got up to fight Teamsters union president Sean O’Brien in the middle of a Senate hearing. 

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