The president tweeted that he "had to fire" Mike Flynn for lying to the vice president and the FBI, which shows he knew his national security adviser had broken the law before asking then-FBI director James Comey to drop the investigation.
The White House insists the tweet was actually written by the president's outside attorney, John Dowd -- who legal experts say is now a witness in the special counsel probe.
"No matter who drafted it, it's still Donald Trump's words, and if John Dowd truly wants to take responsibility, he has to resign from the president's legal team," Sen. Richard Blumenthal (D-CT) told MSNBC's "Morning Joe." "He's going to be a witness in a trial at some point -- and no telling which side he'll be a witness for -- but I think now these threats and intimidation raise the specter of political interference in this investigation, much like the 'Saturday night massacre,' and I'm going to press the Judiciary Committee to move forward with legislation protecting the special counsel. It's bipartisan, and we have five co-sponsors. We have no choice but to move forward."
Legal analyst Jonathan Turley greed that Saturday's tweet was Exhibit A in a possible charge of obstruction of justice against the president.
"Oh, of course it is, it can be evidence -- it goes to state of mind," Turley said. "It can be evidence of obstruction. Obviously the White House is now denying that these were his words, but it creates a series of problems for the legal team. I mean, this is a team that's already had trouble. It's like Monty Python's crack suicide squad -- they show up with an oppressive army and die at your feet. We saw this earlier, a Trump lawyer making a public admission of withheld documents by the White House counsel at a restaurant. We now see this."
Turley said Dowd could be compelled to testify against Trump.
"The problem is that there's a crime fraud exception to attorney-client privilege," Turley explained. "Dowd put himself in the middle of this investigation. There's no reason why the special counsel should take the word that the president didn't write or dictate this language -- it goes to the heart of obstruction. It could not be worse. It's baffling to see this stumbling by the Trump legal team continually."
Joyce White Vance, a former U.S. attorney, said the president's tweets have previously been used as evidence in court, so there's no reason this one would be any different.
"We've now seen judges in the Muslim ban line of cases hold Trump accountable for his tweets, saying that, in essence, they are public and official statements," Vance said. "But I think it goes a little bit beyond that. We're talking about the president of the United States, and when he takes words written by someone else and puts them out there as his own, I think he owns those words, and it's going to be very difficult for him to back away from them, no matter who drafted them."
"Morning Joe" host Joe Scarborough said it was a distinction without a difference, and he pointed out the White House has already stated that Trump's tweets are official statements from the Oval Office.
"The only thing they've done by denying it is made matters even worse," Scarborough said.
Blumenthal said the president had only one option for making things right.
"Where is the president saying, 'I disavow this tweet, it was my lawyer, I never saw it -- and i'm firing him?" Blumenthal said.
The senator said the president's tweet also exposed top administration officials to legal jeopardy.
"These words are his, it doesn't matter who drafted them or how many drafts there were," Blumenthal said. "He owns the words, he has to take responsibility and there's no reason they are not evidence in a criminal prosecution against, by the way, someone else as well. I think the question of what did they know and when did they know it has to be asked about Pence, Sessions (and) Kushner, because the Flynn statement of facts implicates others in the transition in the campaign, as well."
