WATCH: Near ‘Literal Brawl’ Starts When GOP Senator Threatens Union Leader Testifying Before Committee

In what was once known as “the greatest deliberative body on earth,” today, a Republican senator threatened to fight a union leader who was testifying before a hearing of the Senate Health, Education, Labor and Pensions Committee.

Teamsters President Sean O’Brien was the witness, according to Mediaite, when Sen. Markwayne Mullin (R-OK) referenced several barbs the two men have traded in recent months.

For example, O’Brien posted this in June:

That led Mullin to tell O’Brien:

“Sir, I wish you was [sic] in the truck with me when I was building my plumbing company myself and my wife was running the office because I should remember working pretty hard and long hours. ‘Pretends like he’s self-made. What a clown, fraud always has been, always will be. Quit the tough guy act in these Senate hearings. You know where to find me. Any place, any time, cowboy.”

Mullin then added: “Sir, this is a time, this is a place. You want to run your mouth. We can be two consenting adults. We can finish it here.”

O’Brien: “Okay, that’s fine. Perfect.”

Mullin: “You want to do it now?”

O’Brien, accepting the challenge: “I’d love to do it right now.”

Mullin: “Well, stand your butt up, then.”

O’Brien: “You stand your butt up.”

As Mullin stood and started to take a ring off his finger, Sen. Bernie Sanders (I-VT) intervened:

“Hold it. Stop it. Stop it. No, no. Sit down. Sit down! You’re a United States senator!”

When O’Brien asked if he could respond to what Mullin had said, Sanders insisted he couldn’t, telling him, “No, you can’t. This is a hearing.”

Here’s the video:

The greatest deliberative body on earth? Sure, until a redneck like Markwayne Mullin tries to turn it into a boxing match.