President Trump’s showdown with Robert Mueller headed toward a crisis point on Tuesday, with the White House saying Trump has legal authority to fire the special counsel.

Republicans unnerved by the president’s anger in public and private sought to talk him down, fearing a “Saturday night massacre”-style series of firings harking back to the Nixon era was growing more likely.

GOP lawmakers fear presidential firings of Mueller, Attorney General Jeff Sessions or Deputy Attorney General Rod Rosenstein would cause chaos in Washington and dim Republican hopes of holding their congressional majorities.

{mosads}Senate Judiciary Committee Chairman Chuck Grassley (R-Iowa) declared in a CNN interview Tuesday that “it would be suicide for the president to fire him.”

“I have made my views public, and I hope he’s listening to those of us who say it would be a mistake,” said Senate Republican Whip John Cornyn (Texas).

Senate Majority Leader Mitch McConnell (R-Ky.) insisted legislation to protect Mueller was unnecessary because cooler heads would prevail.

“I haven’t seen a clear indication yet that we needed to pass something to keep him from being removed because I don’t think that’s going to happen, and that remains my view,” McConnell told reporters. “It’s still my view that Mueller should be allowed to finish his job. I think that’s the view of most people in Congress.”

Trump’s fury at the FBI’s raid on Monday on Michael Cohen, his personal lawyer, has triggered the latest crisis surrounding the Mueller probe.

Federal prosecutors were reportedly seeking information on payments made to two women, adult-film actress Stormy Daniels and former Playboy model Karen McDougal, who both claim to have had affairs with Trump years ago.

The personal nature of the probe has clearly angered the president, who decried an unfair witch hunt of his presidency in a Tuesday morning tweet.

“Attorney–client privilege is dead!” Trump tweeted. “A TOTAL WITCH HUNT!!!”

The president also canceled a planned weekend trip to two South American nations.

Allies of Trump were egging him on, saying they would understand if he took the step of firing officials at the Department of Justice — a decision some Republicans have said could spark a constitutional crisis.

“I understand the president’s frustration with the hypocrisy playing out at the Department of Justice,” freshman Rep. Matt Gaetz (R-Fla.) told Fox News. “Frankly, it would be warranted if we made changes at the very top of the Department of Justice.”

“I think there is a sufficient basis to fire Rosenstein in particular, and likely the attorney general for not doing his job,” he added.

That suggestion shocked other Republicans.

“If the president were to fire the deputy attorney general, that would be an extraordinary crisis and a real problem, and I just don’t think he’s going to do it,” said Sen. Susan Collins (R-Maine).

GOP lawmakers couldn’t escape questions about Trump, Cohen, Mueller and Rosenstein from reporters at the Capitol — even on a day when Facebook CEO Mark Zuckerberg was testifying on Capitol Hill for the first time.

Pushback from fellow Republicans against firing Mueller has grown stronger since the beginning of the year, when Trump’s allies mostly shrugged off speculation that the president would somehow cut short the special counsel investigation, dismissing it as an unlikely prospect.

While most Republicans maintain they don’t think Trump will quash the probe, they’re less confident than before.

And statements from the White House podium on Tuesday from press secretary Sarah Huckabee Sanders only added to their fears.

Sanders announced that Trump “certainly believes that he has the power” to end Mueller’s investigation. The comments suggest the White House may be looking for legal arguments to back a decision to fire Mueller.

Legal experts say Trump does not have the power to fire Mueller directly. Under Justice Department regulations, that authority falls to the agency official in charge of the investigation — in this case Rosenstein.

It is easy to see why a Trump decision to fire Mueller would make Republicans queasy.

A Quinnipiac University poll conducted this month found that 69 percent of American voters oppose Trump firing Mueller while only 13 percent support it. More than half of the Republicans polled, 55 percent, said Trump shouldn’t interfere.  

Republicans are worried about a wave election this fall that could cost them their House majority. There are also fears about the Senate, though the fact that Democrats are defending many more seats in the upper chamber gives Republicans more confidence about holding it.

Still, many GOP senators fear firing Mueller would pose new risks to their majority.

Trump also has reason to fear a Democratic takeover of the House and Senate, which would unleash investigations of his administration.

Amid uncertainty over what Trump will do next, some Republicans are pushing for legislation to protect Mueller, although that path doesn’t yet have much support in the party.

Sens. Thom Tillis (R-N.C.) and Lindsey Graham (R-S.C.) have sponsored bipartisan bills to protect the special counsel.

The Tillis measure would empower judges to reinstate Mueller if a court found his firing to be improper. Tillis on Tuesday called for a vote on the measure.

Senate Democratic Leader Charles Schumer (N.Y.) tried to ramp up pressure on Republicans Tuesday by defending the integrity of Mueller’s work and calling for Senate floor action. 

– Jordain Carney contributed