Teamsters boss Sean O'Brien endorses Sen. Markwayne Mullin for DHS chief, two years after their viral Senate hearing nearly turned into a physical fight.

Well, stand your butt up, then,” Mullin had said to the Teamsters chief at a Senate hearing as he got up to potentially fight. He was selected to head the Department of Homeland Security on Thursday a

"The senator broke his hand, a sitting U.S. Senator just broke the hand of a Marine!" yelled other people in the room, although it remained unclear if any injuries occurred.

Sen. Tim Sheehy, R-Mont., attempted to help police remove the veteran, Brian McGinnis, from the congressional hearing.

Brian McGinnis, a U.S. Marine veteran and North Carolina Senate candidate, protested while dressed in uniform at the testimony of several U.S. generals.

Sen. Tim Sheehy, R-Mont., assisted Capitol Police officers in arresting a man protesting the war in Iran during a Senate hearing Wednesday.

Sen. Tim Sheehy (R-Mont.) assisted Capitol Police in forcibly removing a protester from a congressional hearing on Wednesday afternoon. Video from the hearing posted online by a CBS News reporter shows the senator helping police officers push Brian McGinnis out of the Senate Armed Services Committee hearing.