Senator Richard Blumenthal said Monday President Donald Trump's ongoing Twitter assault on Rep. Elijah Cummings and the city he represents, Baltimore, are "despicable," and "a profound disservice to our nation." 

Trump has characterized Baltimore in his tirade as "a rodent-infested mess," where "no human being would want to live." He also launched personal attacks on Cummings, calling him "racist" and "incompetent."

Senator Chris Murphy reacted strongly to the attack saying he's tired of waiting for his Republican colleagues to speak out about the president's rhetoric.

"I think this week you can't make the case any longer that it could get any worse," said Murphy on MSNBC's Morning Joe. "He is literally setting this country on fire. So, many of us who have listened to the argument from our Republican friends who tell us -- don't take away our ability to try to talk to him and influence him quietly -- we're going to call that out as the BS that it is."

Trump's announcement of a nominee to replace outgoing Director of National Intelligence Dan Coats also drew a swift reaction. Trump said he wants Texas representative John Ratcliffe to succeed Coats in the role.

Both Blumenthal and Murphy said they will continue to learn more about Ratcliffe, who has been styled by many commentators as a Trump loyalist, but both are concerned at the development.

Murphy called Ratcliffe "a very inappropriate choice," when the country is trying to lift national security out of the realm of politics.

"The resignation of Dan Coats is not good news for the fight against foreign interference in our elections," said Blumenthal at a press conference in Hartford, "because he was one of the leading advocates and champions of stronger action to protect our democracy against these invasive attacks from foreign powers."

Blumenthal continues to call for more congressional action on election security. Last week he attempted for the third time to bring a bill to the floor of the Senate which would strengthen oversight of attempts by foreign governments to interfere in campaigns.

The Duty to Report Act would mandate that the FBI be notified of any foreign attempts to contact campaign staff.

Asked by reporters if he believed it was time to move forward with impeachment hearings in the House of Representatives, Blumenthal stopped short of calling out his congressional colleagues, but said it is time for action.

"This president must be held accountable, either through the courts, or through congress and impeachment hearings, or through the court of public opinion and the ballot box," he said. "There must be hearings, they must move forward with the witnesses -- call those hearings whatever you wish, impeachment hearings, investigative hearings, oversight hearings."

And he left no doubt about his opinion of the president's conduct as outlined in the report of special counsel Robert Mueller.

"The president has done so much that is illegal beyond a reasonable doubt," said Blumenthal. "As I have said with a thousand of my fellow former prosecutors, he would be in handcuffs as a criminal defendant if he were not a sitting president."