In 1998, Republicans were quick to impeach then President Bill Clinton after he lied under oath about an affair with an intern. Twenty years later, Republicans are facing the very real possibility that their party leader committed Obstruction of Justice and collided with an enemy nation to win an election.

While Trump’s supporters are slow to acknowledge the legal danger, a growing number of Republican elected officials and strategists fear that a battery of new revelations in the far-reaching Russia investigation has dramatically heightened the legal and political danger to his presidency — and threatens to consume the rest of the party, as well.

Trump added to the tumult today by announcing the abrupt exit of his chief of staff, John Kelly, whom he sees as lacking the political judgment and finesse to steer the White House through the treacherous months to come.

According to The Washington Post, Trump remains headstrong in his belief that he can outsmart adversaries and weather any threats, according to interviews with 14 administration officials, presidential confidants and allies, some of whom spoke on the condition of anonymity to candidly discuss private exchanges.

But anxiety is spiking among Republican allies, who complain that Trump and the White House have no real plan for dealing with the Russia crisis while confronting a host of other troubles at home and abroad.

Mueller’s latest court filings offer new evidence of Russian efforts to forge a political alliance with Trump before he became president and detail the extent to which his former aides are cooperating with prosecutors.

Some GOP senators were particularly shaken by this week’s revelation that former national security adviser Michael Flynn had met with Mueller’s team 19 separate times — a distressing signal to them that the probe may be more serious than they had been led to assume, according to senior Republican officials.

Even in the friendliest quarters, there are fresh hints of trouble.

Fox News Channel host Tucker Carlson, a reliable prime-time booster of the president, faulted Trump in an interview this week for failing to keep his main campaign promises, understand the legislative process and learn how to govern effectively.

For now, Republicans on Capitol Hill are still inclined to stand by Trump and give the president the benefit of the doubt.

But one pro-Trump senator said privately that a breaking point would be if Mueller documents conspiracy with Russians.

“Then they’ve lost me,” said the senator, noting that several Republican lawmakers have been willing to publicly break with Trump when they believe it is in their interests — as many did over Saudi Arabian Crown Prince Mohammed bin Salman’s role in the brutal killing of dissident journalist Jamal Khashoggi.

Sen. Richard Blumenthal (D-Conn.), an outspoken Trump critic and a frequent subject of his ire, said, “The president’s situation is fraught with mounting peril, and that’s apparent to everyone who’s paying any attention, which is all of my Republican colleagues.”

Democrats are preparing to seize control of the House in January with subpoena power to investigate corruption.

The White House is adopting what one official termed a “shrugged shoulders” strategy for the Mueller findings, calculating that most GOP base voters will believe whatever the president tells them to believe.

But some allies fret that the president’s coalition could crack apart under the growing pressure.

Steve Bannon, the former Trump strategist who helped him navigate the most arduous phase of his 2016 campaign, predicted 2019 would be a year of “siege warfare” and cast the president’s inner circle as naively optimistic and unsophisticated.

“The Democrats are going to weaponize the Mueller report and the president needs a team that can go to the mattresses,” Bannon said. “The president can’t trust the GOP to be there when it counts. They don’t feel any sense of duty or responsibility to stand with Trump.”

Trump critics, like retiring Sen. Jeff Flake (R-Ariz) — who has sponsored legislation that would protect Mueller but has been largely ignored by his colleagues — warned that the drumbeat of Trump loyalists in Congress, along with the president’s relentless clashes with Mueller, have lulled Republicans into a dangerous place.

“It’s like the party is a frog slowly boiling in water, being conditioned to not be worried, to not think too hard about what’s happening around them,” Flake said. “They feel at a loss about what to do because it’s the president’s party, without any doubt. So, there’s a lot of whistling by the graveyard these days.”

Rudy Giuliani, Trump’s attorney, dismissed Flake’s criticism in much the same way he and the president have taken on Mueller — with a barbed character attack rather than a measured rebuttal.

“He’s a bitter, bitter man,” Giuliani said of Flake. “It’s sick. Nobody likes him and they would like him gone.”

Rather than building a war room to manage the intersecting crises as past administrations have done, the Trump White House is understaffed, stuck in a bunker mentality and largely resigned to a plan to wing it.

Political and communications operatives are mostly taking their cues from the president and letting him drive the message with his spontaneous broadsides.

“A war room? You serious?” one former White House official said when asked about internal preparations. “They’ve never had one, will never have one. They don’t know how to do one.”