WASHINGTON — Sen. Markwayne Mullin, an Oklahoma Republican, challenged the head of the Teamsters union to a physical fight at a U.S. Senate hearing Tuesday intended to showcase how labor unions are making families’ lives better.

The tense confrontation at the Senate Health, Education, Labor and Pensions Committee hearing stemmed from acrimonious posts on social media, as well as a confrontation between the two at an earlier Senate hearing.

Tuesday’s episode started after Mullin read aloud one of Teamsters chief Sean O’Brien’s posts on X, formerly known as Twitter. In the post, O’Brien had called Mullin a “greedy CEO who pretends like he’s self made.”

O’Brien, general president of the International Brotherhood of Teamsters, ended the post by writing, “You know where to find me. Anyplace, Anytime cowboy.”

“So this is a time, this is a place,” said Mullin, who has a mixed martial arts background, to O’Brien, seated at a witness table in front of him. “You want to run your mouth, we can be two consenting adults. We can finish it here.”

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

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

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

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

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

Both men rose to their feet. Committee Chairman Bernie Sanders, an 82-year-old Vermont independent, intervened, and called for them to sit down.

“You’re a United States senator,” Sanders told Mullin. “This is a hearing. God knows the American people have enough contempt for Congress, let’s not make it worse.”

For Mullin’s remaining time asking questions of O’Brien and other witnesses, the two continued to throw verbal insults at each other. Sanders pounded his gavel and shouted over them in attempts to shut down the heated exchange.

“We’re not here to talk about fights or anything else,” Sanders said.

Mullin and O’Brien also had a tense moment at a previous committee hearing back in March. In another post on X,? O’Brien told Mullin, “Sounds like you need to shut your mouth & get to work for the people of your state.”

UAW strike

Another main witness at the hearing, titled “Standing Up Against Corporate Greed: How Unions are Improving the Lives of Working Families,” was Shawn Fain, president of the United Auto Workers.

The union reached tentative agreements at the end of October with the “Big Three” automakers — Ford Motor Co., Stellantis and General Motors. The strike began in Detroit in mid-September, but expanded to more than 20 other states.

“The working class needs this committee and the entire Congress to step up,” Fain said. “You all have an essential role to play, not only supporting our fights and other fights like ours, but to finish the job for economic and social justice for the entire working class.”

Fain spoke about the success of the UAW’s strike and the ripple effect it has had. He referenced that auto companies Honda, Toyota and Hyundai have raised wages since the UAW agreements.

“In less than seven weeks, we won justice for our members and other workers,” Fain said.

Fain said the UAW’s efforts helped significantly raise wages for over 100,000 workers, improve retirement security, secure jobs and ensure workers have “a just transition” to making electric vehicles.

This transition would allow autoworkers to “flow” into a new job of making batteries for electric vehicles, Fain said.

Legislative efforts

Sanders, who supported the UAW’s strike, highlighted his legislation — the Protecting the Right to Organize Act, otherwise known as the PRO Act — as a means to make organization easier for American workers.

Ranking member Bill Cassidy, a Louisiana Republican, said the PRO Act faces opposition from his party.

U.S. Sen. Tammy Baldwin, a Wisconsin Democrat, said she is working on legislation that would require the Federal Trade Commission to additionally “consider the impact of mergers on workers.”

“The workers are the ones who bear the brunt of the quote-unquote ‘efficiencies’ found after a consolidation,” Baldwin said.

Protecting the right to unionize

Labor organizers called for more action by Congress to help U.S. workers.

The International Brotherhood of Teamsters is a labor union with members across diverse occupations. The largest employer in the Teamsters union is UPS, which reached a collective bargaining agreement earlier this year. This agreement raised wages and improved workplace conditions for UPS workers.

“We need our elected officials to do more and do what’s right,” O’Brien told senators.

Sara Nelson, the president of the Association of Flight Attendants-Communication Workers of America, said labor unions are “necessary for a stable economy, our safety, our security and our democracy.”

Republican witnesses included Diana Furchtgott Roth, the director of the Center for Energy, Climate, and Environment and the Herbert and Joyce Morgan Fellow in Energy and Environmental Policy at the Heritage Foundation, and Sean Higgins, a research fellow at the Competitive Enterprise Institute in Arlington, Virginia.

The Heritage Foundation and the Competitive Enterprise Institute are both conservative think tanks.

Higgins said the increased wages as a result of union strikes could increase inflation.

In response, Fain later said the idea that raising wages negatively impacts the economy is rooted in “fearmongering.” Fain said when unions bargain for a contract that includes higher wages, the opposition often believes “the world’s going to end because working class people make a livable wage, and it’s going to drive the price of vehicles up.”

Sen. Robert P. Casey Jr., a Pennsylvania Democrat, said a worker’s right to unionize “is under threat.”

“Every day of the week, that right is under threat across the country,” Casey said. “That right to organize is essential to building an economy that works for all Americans.”