In circulating the senator's letter to FCC chair Ajit Pai, Blumenthal's office cited the president's tweet last week in which he raised the notion via Twitter, posting: “With all of the Fake News coming out of NBC and the Networks, at what point is it appropriate to challenge their License? Bad for country!”
Trump got even tougher in a subsequent tweet, saying: "Network news has become so partisan, distorted and fake that licenses must be challenged and, if appropriate, revoked. Not fair to public!"
Blumenthal wants Pai to issue a written statement by Nov. 1 outlining his position on Trump's statements.
"I ask for your unwavering commitment that you will ensure the First Amendment remains a cornerstone of our democracy and that you will not follow through on this direction from the president," Blumenthal wrote, saying Pai needed to demonstrate that he would not be "bullied into abandoning our core values."
Pai has said he would not do anything to abridge the freedom of speech, even if pressured by the administration to do so, but Blumenthal and other Democrats want a new and specific repudiation of the president's attacks.
Trump was prompted by an NBC News story that he was considering massively boosting the nation's nuclear arsenal, a story Trump said was "fake news" and "pure fiction."