Sen. Marco Rubio on Wednesday invoked the fall of the Roman Empire in speaking about the decision of his Senate colleague Jeff Flake to retire.

“I’m not saying America is Rome, but if you look at the history of Rome, … one interesting thing about Rome at its peak, one of the things that Rome did very well was it was able to include people,” the Florida Republican said. “In essence, at the peak of the Roman Empire, they had Britons, Spaniards, North Africans, Greeks, Egyptians, they were very good at integrating people.”

Rubio identified two factors that led to Rome’s collapse, including what he described as “kind of a recalcitrant Senate that refused to address the issues of the day.”

Comparing the U.S. Senate to the Roman Senate isn’t new. West Virginia Democratic Sen. Robert C. Byrd gave 14 floor speeches, starting in 1993, about the history of Rome, imploring his colleagues to reject the line-item veto proposal pushed by President Bill Clinton.

The measure was ultimately determined to be unconstitutional, but it did become law. Byrd’s warning was against a weakening of the Senate relative to the executive (the emperor, in Rome’s case).

“The United States Senate would have set its foot on the same road to decline, subservience, impotence, and feebleness that the Roman Senate followed in its own descent into ignominy, cowardice, and oblivion,” Byrd said.

Rubio said the Roman Senate was only part of the problem.

“They just dug in, they wouldn’t move on anything. And so a lot of bad things got ahead of them, they never fixed it,” he said, according to a transcript posted by a CNN producer. “And the other thing that doesn’t get enough attention is there was a complete and total breakdown of societal norms and behaviors.”

Rubio made his remarks at a pen-and-pad session Wednesday with a variety of journalists on the importance of the child tax credit. Some media outlets, including this publication, were not invited to participate.

Rubio, who ran for president in 2016, described President Donald Trump as a vessel for the frustration of many Americans about political correctness going too far.

He also suggested there should be more personal responsibility.

“We have to understand that a republic really can’t function unless there are some norms of behavior that are not legally prescribed or in the law. It’s just the way human beings should conduct themselves in interacting with one another,” Rubio said. “Everybody will handle it differently, and I don’t always pass this test but what I try to do is I try to behave the way I think people in these positions should behave, and model that behavior.

“From a policy perspective … everybody makes their own decision, you’ll have to ask Jeff [Flake] and you’ll have to ask Bob Corker why they reached the point that they reached,” Rubio said of his GOP colleagues who have said they will retire at the end of 2018. “I have disagreements with the White House and I have been able to address them privately and a couple of them more publicly.”