A liberal ex-governor walks into a bar, followed by a conservative Trump administration official.

Instead of a punchline, what followed, one witness said, was a “shame-invoking tirade” by Martin O’Malley, the former Democratic governor of Maryland, directed at Ken Cuccinelli II, the former Virginia attorney general who is acting deputy secretary of the Department of Homeland Security.

The two political polar opposites crossed paths Wednesday night at the Dubliner, a Capitol Hill Irish pub popular on Thanksgiving Eve with Gonzaga College High School graduates. Both men attended the school, graduating five years apart in the 1980s, and both said they were there to visit with former classmates.

Siobhan Arnold, who was visiting from Philadelphia, had just met O’Malley at the bar when Cuccinelli walked in. Soon the two men were face-to-face, she said, with O’Malley excoriating Cuccinelli over the Trump administration’s immigration policies.

O’Malley said “something about his [Cuccinelli’s] grandparents,” Arnold said in an interview. Cuccinelli said little if anything in reply, she added, quickly leaving the area.

“O’Malley was shouting,” Arnold said. “I don’t think Cuccinelli was responding. I think he’s like, ‘Time to go. Just got here and I’m leaving.’ He pretty much retreated.”

O’Malley disputed Arnold’s account on one point: He said in a text message that he wasn’t shouting, but raised his voice “just to be heard” in the pub.

Both O’Malley and Cuccinelli described a confrontation that involved O’Malley hotly criticizing Cuccinelli’s politics. And both said they eventually ended up face-to-face with O’Malley asking Cuccinelli if he wanted to throw a punch.

But the men disagreed on who invaded the other’s personal space. Cuccinelli said O’Malley, after pushing through a group, bumped up against him, an action O’Malley denied. O’Malley said Cuccinelli “put his chest up in mine, to which I said, ‘What is it, Ken? You want to take a swing?’”

O’Malley, a former Baltimore mayor who was Maryland governor from 2007 to 2015, unsuccessfully sought the Democratic presidential nomination in 2016. He said that when he spotted Cuccinelli, he unloaded his frustration at the Trump administration’s separation of migrant children from their parents and detention of immigrants in chain-link enclosures at the southern U.S. border.

“We all let him know how we felt about him putting refugee immigrant kids in cages — certainly not what we were taught by the Jesuits at Gonzaga,” O’Malley said in a text.

In an emailed statement, Cuccinelli said that as he walked to a bar to order a Guinness, he heard cussing and turned to see O’Malley. “For a moment, I thought he was trying to be funny.”

He said he knew that O’Malley was serious when the yelling continued “to the point of veins bulging on his neck.” One or two other people also started cursing at him, Cuccinelli said.

He said he ignored O’Malley and the others, and walked to a different bar within the Dubliner. O’Malley followed, Cuccinelli said, “still cursing me, the President and my Italian ancestry.”

He said that when O’Malley invited him to take a swing, “I said ‘Martin, one of us has to rise above this, and it’s obviously not going to be you.’”

“Martin’s behavior was as sad as it was shocking,” Cuccinelli said.

In a phone call Thursday, O’Malley did not dispute that he used “very direct and colorful” language to express his displeasure with Trump administration policy, but he denied insulting Cuccinelli’s Italian ancestry. Instead, O’Malley said he told Cuccinelli that his immigrant grandparents “would be ashamed of him putting children in cages on our southwest border.”

Cuccinelli, who narrowly lost the race for Virginia governor to Terry McAuliffe (D) in 2013, was an immigration hard-liner long before joining the Trump administration. (O’Malley, in contrast, was governor when Maryland approved driver’s licenses and in-state tuition for undocumented immigrants, and has been an outspoken advocate for “dreamers.”)

In 2015, Cuccinelli accused President Barack Obama of encouraging “an invasion” of undocumented immigrants. As a state senator, he sponsored a bill to strip U.S.-born children of those immigrants of their citizenship.

He eased up on his anti-immigration positions at one point during the governor’s race, removing from his website a statement saying he had “voted consistently against in-state tuition for illegal aliens.” (As a state senator, he supported a bill that would have gone further, banning undocumented immigrants from attending state colleges at all.)

Arnold tweeted about Cuccinelli’s encounter with O’Malley and was surprised hours later to hear that the tweet was going viral. She said that she normally posts to the social media site for work, as a public relations official for Villanova University, and that her audience is limited.

“I’m usually tweeting about research findings,” she said.