The president’s optimistic, even nonchalant attitude melted away this week in a series of sudden developments as he crisscrossed meetings at the United Nations in New York. Trump and a coterie of aides were stunned by a swift progression of events that upended their longtime thinking about how an impeachment scenario would proceed. By the time they returned to the White House Thursday, they had tested and retested strategies on the fly as they began to recognize the perilous road ahead that would likely look far different from anything this president or any of his predecessors faced.

“It should never be allowed, what's happened to this president,” Trump told reporters upon stepping off Air Force One.

House Speaker Nancy Pelosi’s rapid move toward impeachment, after months of stalling, reflected her recognition of a new political reality: The contents of Trump’s call with the Ukrainian president, in which he used his sacred perch in the White House to ask a foreign leader to investigate a political rival, could push Trump into feisty and perilous territory — testing public opinion and congressional patience in a drama-filled election season. The swiftness of Pelosi’s action caught the White House by surprise.

White House aides and allies do not expect the president to calm down anytime soon. Many worry impeachment proceedings will sour the president’s mood and his ability to focus on legislation, any other substantive policy matters or even key elements of the 2020 campaign, much the way Mueller dominated his attention.

Interviews with more than a dozen White House aides, former administration officials, Republican operatives and close Trump allies showed little consensus on either the best course of action ahead or the consequences for Trump and his presidency.

The White House and Trumpworld are expected to test countless new strategies in the weeks and months ahead, just as they did in recent days.

The White House attempted to first bat down the controversy by stonewalling Congress on getting the whistleblower complaint. Then the administration veered toward transparency by releasing a summary memo of the call between Trump and the Ukrainian leader, and then the whistleblower complaint. Republican talking points tried to cast the rough call transcript as a vindication for the president, a “muddy” document as one former senior White House official put it.

Still, the president believed his sudden embrace of transparency would exonerate him, even if he and two Cabinet members worried about the precedent of releasing notes of calls with foreign leaders.

But by Thursday, the administration and allies moved into a new phase of attempting to discredit the whistleblower, whose complaint kicked off the events that brought Trump to this point. Republicans, privately and vaguely, tried to cast the whistleblower as a partisan figure without offering any evidence, while Trump reportedly referred to the whistleblower as a spy.

But some former aides also say Trump himself has made things much worse for himself with his changing story, a reflection of the president’s long-held approach to decision-making.

“You get one version of the story, and then you go, ‘Oh okay.’ But then you go, ‘Oh wait, there’s another version. We forgot to tell you these 10 other things,'” said one of the former senior White House officials. On calls with foreign leaders, the president “has a comfort level where he says whatever is on his mind.”

After days of differing messages offered between his U.N. meetings, the president spent part of Thursday taking Twitter jabs at both the whistleblower and Democrats. “Liddle’ Adam Schiff, who has worked unsuccessfully for 3 years to hurt the Republican Party and President, has just said that the Whistleblower, even though he or she only had secondhand information, ‘is credible.’ How can that be with zero info and a known bias. Democrat Scam!” Trump tweeted Thursday afternoon, shortly after he arrived back at the White House.

Campaign aides and advisers maintain the impeachment inquiry only helps motivate Trump’s extremely loyal base as well as his fundraising. The campaign and Republican National Committee raised an estimated $8 million this week from a dinner and breakfast in New York, which featured the president as a special guest.

“Pelosi sacrificed Biden’s presidential campaign to get Trump, and now Elizabeth Warren is going to be the nominee, which I think every Trump person with a brain would prefer,” said a person close to the campaign.

Republicans and White House advisers’ greatest comfort now comes from the wonky mechanics of impeachment, which will give the Senate the final say about the fate of Trump’s presidency. Few think Senate Majority Leader Mitch McConnell will allow the Senate proceedings to drag on. Republicans’ confidence in Trump’s ability to survive this scandal appears to largely rest with McConnell and his grip on his caucus, not necessarily with the White House.

A White House official claimed there “is a very positive mood” in the building. “Everybody's just absolutely thrilled.”

The White House press secretary and communications director, Stephanie Grisham, said the president and his aides’ view of impeachment has not changed in the last week. “Nothing has changed. The president did nothing wrong,” Grisham said.

“What these guys are doing — Democrats — are doing to this country is a disgrace and it shouldn’t be allowed,” Trump told reporters Thursday afternoon. “There should be a way of stopping it — maybe legally, through the courts. But they're going to tie up our country. We can't talk about gun regulation. We can't talk about anything because, frankly, they're so tied up. They're so screwed up, nothing gets done — except for when I do it.”

Public opinion has rapidly shifted over the week, with the number of Americans who support impeachment on the rise.

Strategizing about the best way to handle the impeachment proceedings and the White House’s release of information happened on Monday night, when the Trump family gathered for dinner at Trump Tower.

Then as soon as White House aides returned to Washington on Thursday afternoon, the West Wing impeachment planning kicked off in earnest.

Acting chief of staff Mick Mulvaney hopes to set up a war room, comprised of political, press and communications aides to help with the administration’s fight. The administration intends to model it after the Clinton White House’s impeachment strategy, which relied on both separate administration staffers and outside surrogates for the political battles.

Grisham said the White House does not need to make any new hires to deal with the impeachment inquiry.

Already, the White House counsel’s office is accustomed to the siege of investigations and Democratic oversight, so the top attorney, Pat Cipollone, and his team are more prepared than the rest of the White House staff, according to two former administration officials and one close White House adviser.

The administration will need to set itself up for a potentially long battle. The impeachment proceedings for President Richard Nixon stretched roughly eight months, ending with Nixon’s resignation. The Clinton proceedings ran for roughly five months, with Clinton acquitted by the Senate.

Several former administration aides and White House advisers worry the West Wing is not staffed robustly enough for this type of prolonged political fight, as filled as it is with family members, junior aides, newcomers or staffers who’ve stayed so long they feel exhausted.

Current and former aides also wonder if this impeachment fight will end up feeling different than the prolonged Mueller investigation. “Some of the White House scandals are awful, and you take the PR hit. Everyone knows it is just a matter of time and the news cycle changes. This is one of those instances where it is less clear,” said a former senior administration official.

Trump critics say the president’s habit of firing aides so habitually may hurt him as Congress looks for witnesses and the president tries to stay on message.

“The president’s HR practices are going to come back to haunt him here because he is uncomfortable apparently with truth-tellers in his inner circle,” said Timothy Naftali, a professor of public service at NYU and a co-author of “Impeachment: An American History.”

“He is likely to not get good advice from the acolytes who are left,” Naftali said. “He does not have Don McGahn anymore to tell him not to cross a trip cord.”

But Trump allies and current and former aides argue the White House has been anticipating the moment of Trump’s impeachment since he first took office.

“It’s like crack cocaine to the Democrats. They can’t not take the hit,” said Michael Caputo, a former Trump 2016 campaign official. “If the Republicans aren’t ready for impeachment after having two and a half years to prepare, then we shouldn’t be in politics,” adding that he believed the White House was “completely prepared” and the Senate, “bullet-proof.”

“This isn’t a strategy to survive. It’s a strategy to thrive through this. It’s a strategy to leverage the Democrats’ obsession with impeachment to defeat them at the polls in November 2020,” Caputo added. “The White House’s strategy should be predicated on public opinion that’s trending in their favor on impeachment.”