Sen. Markwayne Mullin, R-Okla., stood up from his seat and threatened to fight Teamsters President Sean O’Brien in a remarkable moment Tuesday during a Senate Health, Education Labor and Pensions committee hearing on unions.

“You want to run your mouth. We can be two consenting adults. We can finish it here,” Mullin said. “Stand your butt up.”

“Stop it. Sit down. Sit down. You know, you’re a United States senator,” yelled committee chair Sen. Bernie Sanders, I-Vt., who was sitting directly next to Mullin. “This is a hearing and God knows the American people have enough contempt for Congress.”

What You Need To Know

  • Sen. Markwayne Mullin, R-Okla., stood up from his seat and threatened to fight Teamsters President Sean O’Brien on Tuesday during a Senate Health, Education Labor & Pensions committee hearing on unions
  • O’Brien, who remained sitting, bickered back with Mullin, telling him to “stand your butt up” as well and saying “I don’t respect you at all”
  • Mullin, a former mixed martial arts fighter, called him a “thug” and continued to press him to physically fight
  • The dispute between the first-year senator and the leader of one of the nation’s largest unions was set off when O’Brien attacked Mullin on X in June. On Tuesday, Mullin read part of one post where O’Brien wrote the senator was a “clown & a fraud” and questioned the millionaire’s depiction of himself as self-made

O’Brien, who remained sitting, bickered back with Mullin, telling him to “stand your butt up” as well and saying “I don’t respect you at all.” Mullin, a former mixed martial arts fighter, called him a “thug” and continued to press him to physically fight.

After the hearing, Mullin responded to a conservative commentator’s podcast invite on X, the social media platform formerly known as Twitter, by posting a picture of himself holding a gun in front of a table of ammunition and more guns with the caption “let’s do it. Anyplace, anytime.”

It wasn’t the first time Mullin pursued a physical confrontation with O’Brien. In June, he challenged the Teamsters president to a charity MMA fight after another intense exchange at a Senate hearing. He did so again on Tuesday, pitching April 30 as the fight date.

The dispute between the first-year senator and the leader of one of the nation’s largest unions was set off when O’Brien attacked Mullin on X in June. On Tuesday, Mullin read part of one post where O’Brien wrote the senator was a “clown & a fraud” and questioned the millionaire’s depiction of himself as self-made.

“Quit the tough guy act in these senate hearings. You know where to find me. Anyplace, Anytime cowboy,” O’Brien wrote alongside a picture of Mullin standing on a box during a 2022 primary debate.

“This is a time, this is a place” Mullin said on Tuesday after reading the post. “You want to do it now?”

“I’d love to do it right now,” O’Brien replied.

O’Brien later said he meant they could have coffee and “discuss our differences” any time at any place, cracking a smile. 

Congress appeared to be in a particularly confrontational mood on Tuesday: Elsewhere on Capitol Hill, Rep. Tim Burchett, R-Tenn., accused Rep. Kevin McCarthy of elbowing him in the kidneys in retaliation for voting to oust the California Republican as Speaker of the House last month.