Republican Senator Markwayne Mullin and Teamsters President Sean O'Brien engaged in a heated confrontation during a hearing chaired by Senator Bernie Sanders. The altercation began when Mullin read incendiary tweets from O'Brien, including one where the union boss appeared to challenge Mullin to a fight. Mullin, a former MMA fighter, responded by telling O'Brien that they could settle their differences "here and now." As Mullin rose from his seat and began to take off his wedding ring, O'Brien reportedly looked terrified. Mullin later described O'Brien as a “thug” and accused him of being all talk and no action.

During the confrontation, Chairman Sanders banged his gavel and ordered both men to sit down. O'Brien later described the incident as “bizarre” and claimed that Mullin had missed the point of the hearing, which was to discuss the value of unions and seek bipartisan relationships. O'Brien also accused Mullin of having a history of intimidation, referencing a 2013 report that alleged Mullin had engaged in intimidating behavior during a union election.

Mullin, in response, criticized O'Brien's salary and accused him of prioritizing his own interests over those of the workers he represents. He argued that unions are responsible for the decline in union membership and highlighted the higher salaries in right-to-work states like Oklahoma.

Both Mullin and O'Brien expressed willingness to meet in a more peaceful setting to discuss their differences. O'Brien stated that despite his disagreement with Mullin, he would still examine any candidate or officeholder who shares his views on protecting working people and their jobs.

The incident between Mullin and O'Brien highlighted the ongoing tensions between Republicans and unions. Mullin's background as a former MMA fighter and his confrontational approach added to the drama of the situation. The confrontation also sparked a larger discussion about the role of unions in American society and the potential for bipartisan cooperation.