Secretary of State Rex Tillerson and Secretary of Defense James Mattis flanking President Donald Trump during a meeting with his Cabinet at the White House. Thomson Reuters

One of President Donald Trump's close friends set off a frenzy Monday night when he told PBS that the president was "weighing" whether to fire Robert Mueller, the special counsel overseeing the investigation into Russian meddling in last year’s election.

"He's weighing that option," the friend, Chris Ruddy, said on "PBS NewsHour" on Monday evening.

Ruddy, the CEO of Newsmax, was seen leaving the West Wing on Monday, but White House press secretary Sean Spicer later said Ruddy had not spoken with Trump about the issue while he was at the White House.

It was only weeks ago that Deputy Attorney General Rod Rosenstein appointed Mueller to lead the FBI's investigation into Russia's election interference and whether any Trump campaign associates colluded with Moscow.

Legal experts, members of Congress, former government officials, and even Ruddy reacted swiftly on Monday night, most with the same message to Trump: Don't do it.

"I personally think it would be a very significant mistake — even though I don't think there's a justification ... for a special counsel in this case," Ruddy said.

"Firing Bob Mueller as special counsel would be an order of magnitude more seismic than firing Jim Comey," said Andrew Wright, a professor of constitutional law at Savannah Law School. "It would be insane even by Trump-era standards."

"It would be a disaster," Republican Sen. Lindsey Graham told Politico. "There's no reason to fire Mueller. What's he done to be fired?"

"If President fired Bob Mueller, Congress would immediately re-establish independent counsel and appoint Bob Mueller. Don't waste our time," Rep. Adam Schiff, the ranking Democrat on the House Intelligence Committee, said on Twitter.

"Let Robert Mueller do his job," House Speaker Paul Ryan said on Tuesday.

And Richard Painter, the top White House ethics lawyer under President George W. Bush, said Trump's consideration "had better be fake news or this presidency will be over very soon."

Ruddy's comments came amid a drumbeat of calls from Trump's supporters and conservative allies for Mueller to step down — despite their initial support for him. Mueller has been staffing up with top attorneys specializing in criminal law and fraud.

"Republicans are delusional if they think the special counsel is going to be fair," former House Speaker Newt Gingrich, a prominent Trump surrogate, tweeted Monday. "Look who he is hiring. Check FEC reports. Time to rethink."

Gingrich told CBS on Tuesday morning that Trump called him Monday night to discuss Gingrich's feeling that Mueller had been playing "a rigged game."

'It's chaos that he can put to bed'

It is not clear, however, that Trump could fire Mueller unilaterally.

"As I understand it, the special-counsel regulations require termination only 'for cause,'" Wright said. "The president would have to convince Rosenstein that there are grounds for termination. If Rosenstein refused, Trump would have to fire Rosenstein. Sound familiar? It would be Saturday Night Massacre city."

The Saturday Night Massacre refers to the resignations of Attorney General Elliot Richardson and Deputy Attorney General William Ruckelshaus on October 20, 1973, after they refused to follow President Richard Nixon's orders and fire Archibald Cox, the special prosecutor investigating Watergate.

"If Rosenstein did remove Mueller, then the investigation would revert to Rosenstein on the org chart," Wright said. "But the political, congressional, and media environment would be just white-hot crazy.'"

Democratic Rep. Eric Swalwell, a member of the House Intelligence Committee, said in an interview that he couldn't understand why Trump didn't just put the speculation to rest.

"He is unnecessarily allowing it to fester, and that is creating more chaos around the Russia investigation," Swalwell said on Tuesday. "It's chaos that he can put to bed by just saying that he does not intend to fire the special counsel."

Swalwell added that Trump seemed to have turned questions surrounding the Russia investigation into "a guessing game," beginning with his unfounded claim in early March that President Barack Obama had his "wires tapped" in Trump Tower before the election. Last month, Trump suggested in a tweet that there may be "tapes" of his private conversations with James Comey, who testified last week that while serving as FBI director he felt pressure from Trump to pull back on the Russia investigation.

"This is all beginning to look intentional," Swalwell said. "It seems that he could answer many of the serious questions out there, but instead he's turned this into a guessing game. The cost of this chaos is that he has brought Washington to a halt at a time that both parties would be better served working on the issues they were elected to address."

When it comes to examining whether Trump sought to obstruct the FBI's investigation into Russia's election interference and whether the Trump campaign played a role, the president's pattern of behavior and past statements about the investigation will most likely come back to haunt him, experts say.

"You may be the first president in history to go down because you can’t stop inappropriately talking about an investigation that, if you just were quiet, would clear you," Graham said Sunday of Trump.

Bob Bauer, who was a White House counsel under President Barack Obama, wrote last month that "what is most remarkable is that the president has willingly created this self-portrait."

"As scandals in the making go, this one may become famous for featuring the president as the principal witness against himself: he seems committed to uncovering any cover-up," Bauer said.