Staunch conservative Senator Markwayne Mullin from Oklahoma broke Senate decorum today as he offered to fight Teamsters President Sean O’Brien.

The outburst came at a Senate Health, Education, Labor and Pensions Committee hearing. Senator Mullin read prior tweets by O’Brien.

“Sir, this is the time, this is the place. You wanna run your mouth? We could be two consenting adults. We can finish it here,” Mullin said .

“OK, that’s fine. Perfect,” O’Brien shot back.

“You want to do it now?” Mullin asked.

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

“Stand your butt up,” Mullin demanded. “

“You stand your butt up,” O’Brien sneered.

Watch the full video below: