Sen. Richard Blumenthal said he will not be thrown off from talking about legislation designed to insulate special counsel Robert S. Mueller III by what the Connecticut Democrat called “slurs” being hurled at him on Twitter by President Donald Trump.

Mueller is overseeing the investigation of efforts by Russia to meddle in the 2016 presidential election, as well as of an expanding web of related activity that may prove criminal in nature.

“There is an ongoing special counsel investigation. It is real. It is based on facts. That is the important issue. That’s what really matters. Our national security and the rule of law are at stake,” Blumenthal said. “I am not going to be distracted or bullied by these slurs.”

[A Senator Out of His Shell, and Under Trump’s Skin]

Trump, who apparently was watching Blumenthal on CNN on Monday morning, called the senator a “phony Vietnam con artist!” in a tweet.