A growing number of Republicans fear that a battery of new revelations in the far-reaching Russia investigation has dramatically heightened the legal and political danger to Donald Trump's presidency - and threatens to consume the rest of the party as well.
Trump added to the tumult 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.
Trump remains headstrong in his belief that he can outsmart adversaries and weather any threats, according to advisers. In the Russia probe, he continues to roar denials, dubiously proclaiming that the latest allegations of wrongdoing by his former associates "totally clear" him.
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.
Facing the dawn of his third year in office and his bid for re-election, Trump is stepping into a political hailstorm.
Democrats are preparing to seize control of the House in January with subpoena power to investigate corruption. Global markets are reeling from his trade war. The US is isolated from its traditional partners. The investigation by Special Counsel Robert Mueller into Russian interference is intensifying. And court filings at the weekend in a separate but related federal case implicated Trump in a crime. Prosecutors accused him of directing illegal hush-money payments to women during his campaign.
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. Stephen Bannon, the former Trump strategist, 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 weaponise 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." 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. "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." Trump's decision to change his chief of staff, however, appears to be a recognition that he needs a strong political team in place for the remainder of his first term. The leading candidate for the job is Nick Ayers, Vice-President Mike Pence's chief of staff and an experienced campaign operative known for his political acumen and deep network in the party.
The departure of Kelly - a four-star general with battlefield experience and deep government know-how - deprives the West Wing of a seasoned leader who was seen by allies as a check on some of the President's most reckless impulses.
Kelly's tenure in the White House came with its successes and failures.
Current and former aides say Kelly brought much-needed discipline to a dysfunctional West Wing. Among Republicans in Congress and military officials, Kelly was seen as an essential steadying hand.
The President has been telling friends that he believes the Special Counsel is flailing and has found nothing meaningful. "It's all games and trying to connect dots that don't really make sense," one friend said in describing Trump's view of Mueller's progress. "Trump is angry, but he's not really worried."
But 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 the revelation that former national security adviser Michael Flynn had met 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.
For now, Republicans on Capitol Hill are still inclined to stand by Trump and give him the benefit of the doubt. But one pro-Trump senator said that a breaking point would be if Mueller documents conspiracy with Russians. "Then they've lost me," said the senator.
Another breaking point could come if Trump pardons his former campaign chairman, Paul Manafort. Trump advisers said they understand that a pardon could be difficult to defend and could prompt rebukes from allies.