Donald Trump faces a murky future after his party lost power in Congress last week. While he remains in denial, Democrats celebrated victories in traditional G.O.P. strongholds. Trump chose confrontation on Friday by picking Stephen Miller as his chief of staff, leaving many to wonder how he will govern now.

As Americans absorb a stunning new political reality, they face a gap between the time they effectively decided to be done with the president and the time he is actually done.

In the days since his defeat, he has sounded like a man in denial.

With his party still picking through the wreckage of a political earthquake, a seemingly oblivious President Trump signed a steel beam for his new White House ballroom and flew to Florida to give a speech on the space program. He seems flat these days, maybe a little dazed.

If Donald Trump is still processing the election that swept his party from power in Congress last week, so too is Donald Trump's America. Both parties are still absorbing the stunning reality of sweeping Democratic victories in states like Texas, Kansas and South Carolina that were long G.O.P. strongholds -- and possibly even Mississippi.

But as clear as the midterm verdict was, the future is cloudier. After a decade in which Mr. Trump has dominated national politics, the country now faces a period of profound uncertainty, an interregnum between the time that Americans effectively decided that they were done with Mr. Trump and the time when he is actually done.

How does an unpopular, lame-duck president spurned by the electorate govern in his final two years in office? How does a shattered Republican Party rebuild itself for a post-Trump era while Mr. Trump himself is still around and unwilling to cede the stage? How do newly empowered Democrats use their new majorities in Congress and define themselves beyond simply being the anti-Trump party?

To those who wondered whether Mr. Trump would choose conciliation or confrontation in response to his party's defeat, his decision on Friday to install Stephen Miller, his top ideological warrior, as the next White House chief of staff provided an answer -- and it was not conciliation. In case the message was not received, on Saturday he posted an offer on social media for Dana White, the Ultimate Fighting Championship chief executive, to be his press secretary. Mr. Trump may be wounded, but a wounded animal can thrash around powerfully.

Yet those in his circle wasted no time looking past him. Two senior members of his team, Vice President JD Vance and Defense Secretary Pete Hegseth, quickly went public with sharply divergent views of the Iran war and the wisdom of prosecuting it. In effect, they began to set the parameters for a debate that will consume their party for the next year.

On Capitol Hill, Speaker Mike Johnson promptly indicated that he would step down, opening a leadership contest for the vanquished Republicans. And Democrats began mapping a path forward balancing the desire to investigate and hold Mr. Trump's team accountable with the imperative of passing legislation addressing voter concerns about the cost of living.

"People are conveying: 'Yes, we feel joy, we feel relief,'" said Representative Hillary Scholten, Democrat of Michigan. "But also: 'Get to work, Congress. We do not want political theater, we don't want drama, we don't want infighting.'"

One thing seems certain -- the days of virtual one-man rule are over. In the nearly 22 months since Mr. Trump took office again, he has sought to impose his will not just over the executive branch but also over big business, the tech industry, major universities, law firms, the central bank, private banks, entertainment, sports, museums, the news media, national parks, the financial sector, the energy sector, the military and nonprofit foundations.

He has turned the prosecutorial power of the F.B.I. and Justice Department against his adversaries and, while he has been blocked at times by judges and grand juries, the Supreme Court has validated many of his assertions of authority. He has sent the National Guard into the streets of Washington and other cities, while turning ICE into a paramilitary force to haul away not just criminals but also otherwise law-abiding undocumented immigrants with deep roots in their communities.

He has even sought to remake the face of Washington, tearing down the East Wing of the White House to make room for his new ballroom-qua-drone-launcher, building a helipad on the South Lawn, proposing a new triumphal arch, renovating the Reflecting Pool, overhauling Lafayette Square and replacing the East Potomac golf course. By his own count the other day, he has created or restored 83 statues, fountains and monuments in the city.

He can still be expected in these final two years to exert power in ways that previous presidents did not, but he will now face pushback from an opposition Congress armed with subpoenas and the power of the purse. Moreover, the fear that consumed private institutions in the early part of his second term and prompted them to buckle under to demands for money, policy changes and personnel decisions has certainly eased. If anything, some of them will now worry about offending the ascendant Democrats by appearing too deferential to Mr. Trump.

"The spell is broken, and the veil of invincibility pierced," said Daniel M. Price, a former international economic adviser to President George W. Bush. "The genuflection is likely to cease, and those who paid tribute -- whether for ballrooms or meme coins or to settle frivolous lawsuits or to make 'documentaries' or to secure regulatory favors or government contracts -- may well be called to account."

Michael Beschloss, a presidential historian, said that no other commander in chief in the past 80 years had touched so many sectors of society, leaving many nervous about what would come next. "It's hard to find any precedent for that kind of sweeping, unpredictable change in any other post-World War II administration," he said. "As a result, you could see apprehension on more than a few faces in this capital."

This might be the most overwhelming moment of whiplash in an era that has been defined by sharp swings: Mr. Trump came out of nowhere in 2016 and shocked the world by winning the presidency, then crashed in defeat four years later and spread lies in an effort to overturn the election and hold onto power. He was indicted, put on trial and convicted, then staged an audacious comeback to reclaim the White House and now has endured what by some measures is the most devastating midterm repudiation of a president in half a century or more.

Through it all the country has been through a plethora of ordeals -- the worst pandemic in a century, the biggest economic upheaval in generations, the most widespread racial unrest in decades, the first sacking of the Capitol since the British invasion of the early 19th century, the disastrous end of one overseas war and the rash start of another. All of which might still not eclipse the impact on society of artificial intelligence in the next few years.

This has certainly been a drama for the ages, one that would have been hard to imagine not long ago.

"We've just been through the looking glass, and Wonderland wasn't Wonderland," said Max Stier, president of the Partnership for Public Service, a nonprofit group that aims to make government work more effectively. "It was craziness and destruction."

Tevi Troy, a presidential historian who previously worked for Mr. Bush, said all the disorder finally got to the public. "Now we're looking at the tumult," he said. "People aren't happy. I think they wanted normal, and they're not getting normal from either party."

No president since Franklin D. Roosevelt has dominated the national conversation for as long as Mr. Trump has. Even while President Joseph R. Biden Jr. occupied the White House, Mr. Trump was still a central focus of attention. He drove dinner-table conversations and drove wedges among families, friends and neighbors. But last week's election suggested that the public has grown weary, even in places he won handily in the past in the South and Sunbelt.

Unlike other presidents who suffered midterm defeats, Mr. Trump has largely not acknowledged the setback. After Mr. Bush's Republicans lost both houses in 2006, he admitted it was a "thumping." After President Barack Obama's Democrats lost the House in 2010, he admitted it was a "shellacking." Mr. Trump, by contrast, has offered no expression of humility or much recognition of public discontent with him.

Like other presidents after midterm defeats, Mr. Trump now faces an inevitable erosion of influence. After President Bill Clinton's Democrats were swamped in 1994, he was left to argue plaintively that "the Constitution gives me relevance." There were echoes of that last week when the White House was reduced to posting an online message saying, "TRUMP IS STILL YOUR PRESIDENT."

Mr. Clinton came back to win re-election two years later, but Mr. Trump does not have that opportunity under the Constitution. Each of the five presidents who were elected twice and served two full terms since World War II -- Dwight D. Eisenhower, Ronald Reagan, Mr. Bush, Mr. Clinton and Mr. Obama -- had an opposition Congress in the final two years of his tenure.

Even so, presidents can still make a difference in that final stretch without Congress, especially in foreign policy, noted Mr. Troy. His old boss, Mr. Bush, after the 2006 midterm elections, surged more troops to Iraq and changing strategy there, helping to turn around the war. Mr. Clinton in his final two years successfully prosecuted the Kosovo war.

"They didn't go away," said Mr. Troy, who is now a senior fellow at the Ronald Reagan Institute. "They didn't have huge legislative accomplishments -- none of them had control of Congress. But they all did important things. Things can and do happen in the last two years."

Indeed, Mr. Trump in his second term has not sought to govern through Congress even when his fellow Republicans were in charge, so in that sense he has less to lose. Other than his tax cut bill, he has pursued his priorities largely through executive action.

Still, time is short and with each passing day, the focus will turn relentlessly to the next presidential election. The first scheduled primary is just 441 days away. And it will be wide open, the first contest since 1976 without a Bush, Clinton, Obama or Trump on the ticket.

"I'm already getting outreach from 2028 contenders who are going to pass through Michigan," marveled Ms. Scholten, the congresswoman. "It's wild."