SALT LAKE CITY (AP) — Supporters of President Donald Trump heckled Republican U.S. Sen. Mitt Romney of Utah in an airport, illustrating divisions in the Republican Party between Trump loyalists and those ready to accept the results of the presidential election.

Romney has been considered Trump’s sharpest GOP critic and is among a group of senators who called for an end to an effort to overturn President-elect Joe Biden’s win. Video of the airport confrontation posted online Tuesday night came as Trump backers around the U.S. traveled to Washington, D.C., for demonstrations as Congress meets to accept the Electoral College vote. It's being contested by some GOP lawmakers, but the effort is all but certain to fail.

Romney, the 2012 GOP presidential nominee, has a deep well of popularity in Utah, but a significant slice of the conservative state’s electorate is angry with him for criticizing Trump, said Damon Cann, a political science professor at Utah State University.

The confrontation “shows how deeply divided we are, not only as a country but how deeply divided Republicans are,” Cann said. Going forward, “Republicans need to find out who the person is who can pull the party together.”

Video of a woman walking up to Romney as he worked on a computer in the Salt Lake City airport and later referring to him as a “disgusting shame” gained widespread attention online and was followed by another clip of people chanting “traitor” at him on the plane.

His counterpart, Sen. Mike Lee, is a staunch Trump supporter but called for civility after the video made the rounds.

“Harassing your political opponents on a plane is not acceptable,” he said in a tweet.

Trump, however, referenced the incident as he took a dig at Romney during a rally Wednesday, saying, “I wonder if he enjoyed his flight in last night.”

Romney shrugged off the airport confrontation in comments to reporters Wednesday, calling it “the nature of politics, unfortunately.” He did not soften his own rhetoric on Trump, saying the president “disrespected the American voters, has dishonored the election system and has disgraced the office of the presidency.”

Romney won’t face another election for nearly four more years, but he’ll likely still feel political repercussions in the form of a primary challenger, Cann said.