On the morning of Nov. 7, 2020, the Saturday after the presidential election, President Donald Trump had just approached the tee box at the seventh hole of his golf course in Sterling, Va., when an aide’s phone rang with news from Jared Kushner : All of the major media outlets, including Fox News, were about to call the presidential election for Democrat Joe Biden.

Mr. Trump had tweeted on the way to the course that he’d won “BY A LOT!” But he displayed none of that all-caps energy as he pressed the phone to his ear. Wearing a dark pullover and slacks with white golf shoes and a matching MAGA cap, Mr. Trump calmly listened to his son-in-law as he strolled across the manicured grass under a clear blue sky. He hung up, nonchalantly handed the phone back to an aide and finished the final 12 holes, as more than a dozen golf carts filled with government aides and Secret Service agents trailed behind him.

“ ‘Don’t worry,’ Mr. Trump told a group of supporters on Nov. 7. ‘It’s not over yet.’ ”

When Mr. Trump finally pulled up to the clubhouse in his customized cart—complete with a presidential seal stitched into the seat—club members cheered him on the back patio. “Don’t worry,” Mr. Trump told them. “It’s not over yet.”

But the election was, in fact, over. What wasn’t finished was the term he’d won four years earlier, and on Nov. 7, one of the most pressing questions for staffers was how to fill his calendar. “Let’s do all the things we didn’t get to do because of all of the distractions, and have fun,” Hope Hicks, a longtime Trump aide, said to the president’s team gathered inside campaign headquarters in Arlington, Va.

Mr. Trump had won far more votes than his team projected, with surprising support from Black and Hispanic men. He was immediately the runaway favorite for the party’s 2024 nomination, and Ms. Hicks was expressing that vibe with her suggestion for a jaunty curtain call. But around the table in a glass-encased conference room, the eldest Trump sons channeled their father’s reaction. “What you’re talking about isn’t even an option,” responded Donald Trump, Jr., who had called into the meeting. “It’s a nonstarter,” Eric Trump added.

Ms. Hicks wasn’t an outlier, however. After the election was called, Trump World mostly assumed that the president would behave rationally at the end of the day. Vice President Mike Pence and Ronna McDaniel, the chairwoman of the Republican National Committee, both met with Mr. Trump in early November and separately told others that he just needed space to process the loss. Ivanka Trump, the president’s eldest daughter and a senior adviser, left some White House officials with the hope her father would invite Mr. Biden to the West Wing.

President Trump and his children Donald Trump, Jr., and Ivanka Trump make their way to board Air Force One, Jan. 4.

President Trump and his children Donald Trump, Jr., and Ivanka Trump make their way to board Air Force One, Jan. 4.

Photo: MANDEL NGAN/AFP/Getty Images

But Mr. Trump wasn’t interested in taking a bow. The decision from his team to give him space only created an opening for outside advisers like Rudy Giuliani, and behind the scenes, Mr. Trump was frantically moving personnel in and out of the administration.

Early on, he attempted to oust Attorney General William Barr. By mid-November, the president secretly offered Mr. Barr’s job to John Ratcliffe, the director of national intelligence. Running the Justice Department was Mr. Ratcliffe’s dream job in Washington, but not like this. If Mr. Ratcliffe accepted, he’d be expected to refute the same briefings he’d provided the president as national intelligence director, which stated that no foreign powers had conspired to corrupt the nation’s voting machines. He turned it down.

Mr. Barr, meanwhile, had reached his breaking point. On Dec. 1, he was meeting with White House counsel Pat Cipollone when they were summoned to the Oval Office. Both knew the sudden meeting was about Mr. Barr’s declaration earlier that day that there was no evidence of widespread voter fraud, contradicting the president’s claims. The two attorneys briefly discussed, only half-jokingly, whether Mr. Barr should hotfoot it for the exits.

Mr. Trump erupted as soon as Mr. Barr walked in the room, ripping through a greatest hits reel of debunked claims of fraud and a more historical inventory of grievances. But the attorney general made clear that he wouldn’t subject himself—or his agency—to repeated insults and accusations, and White House officials panicked that he was about to quit. The West Wing had mostly emptied by December, and some viewed Mr. Barr as one of the few remaining adult voices in the administration. Others knew it was a better look for Mr. Trump to push someone out than to have them walk away.

Mr. Barr left the West Wing. His black sedan was pulling out of the parking lot when Mr. Cipollone suddenly appeared and banged his hand on the back window. The White House attorney climbed into the car and cautioned against making any rash decisions. Mr. Barr agreed. But he regretted it, and resigned two weeks later.

“ ‘The crazies have taken over,’ Secretary of State Mike Pompeo warned a colleague. ”

By then, the president was personally phoning U.S. attorneys—against Justice Department protocol—urging them to focus on election fraud. He’d replaced a lineup of veteran defense and intelligence officials with inexperienced loyalists hungry to appease the boss. Gen. Mark Milley asked some Pentagon officials whether the new hires had ties to neo-Nazi groups.

“The crazies have taken over,” Secretary of State Mike Pompeo warned a colleague. Privately, the nation’s top diplomat worried that foreign adversaries might try to exploit the domestic instability. He conveyed concern to others that Mr. Trump might be more willing to engage in an international conflict to strengthen his political argument for remaining in office. Mr. Pompeo organized a daily call with Gen. Milley and Mark Meadows, the White House chief of staff.

Vice President Mike Pence and House Speaker Nancy Pelosi preside over a joint session of Congress to count Electoral College votes, Jan. 6, 2021.

Vice President Mike Pence and House Speaker Nancy Pelosi preside over a joint session of Congress to count Electoral College votes, Jan. 6, 2021.

Photo: Kevin Dietsch/UPI/Bloomberg News

By January, Mr. Trump’s attention had turned to his vice president, who was responsible for presiding over the Jan. 6 congressional certification of the election. The two men had debated for weeks whether Mr. Pence could reject the results.

But the vice president wasn’t practiced in confronting Mr. Trump. The only example some administration officials could remember was in 2018, when Mr. Pence’s political committee hired Corey Lewandowski, the president’s ubiquitous adviser. Mr. Trump was holding a newspaper article about the hiring and said it made him look weak, like his team was abandoning him as he was probed for his campaign’s role in Russian election meddling. He crumpled the article and threw it at his vice president. “So disloyal,” Mr. Trump said.

Mr. Pence lost it. Mr. Kushner had asked him to hire Mr. Lewandowski, and he had discussed the plan with Mr. Trump over lunch. Mr. Pence picked up the article and threw it back at Mr. Trump. He leaned toward the president and pointed a finger a few inches from his chest. “We walked you through every detail of this,” Mr. Pence snarled. “We did this for you—as a favor. And this is how you respond? You need to get your facts straight.”

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Three years later, the moment seemed to call for another get-your-facts-straight lesson from Mr. Pence. But the vice president’s team believed he’d been clear with the president that he didn’t have the constitutional authority to overturn the vote. “Anything you give us, we’ll review,” Mr. Pence told the president during a meeting on Jan. 5. “But I don’t see how it’s possible.” Mr. Trump later insisted that his vice president never told him no.

That night, after meeting with Mr. Pence, the president summoned aides into the Oval Office. He opened the door to the colonnade and told staff to sit and listen to his supporters celebrating near the Ellipse, the site of the Save America rally the following day. As aides shivered in the wintry breeze that filled the room, Mr. Trump signed a stack of legislation and bobbed his head to the classic rock blaring outside—precisely the kind of music he’d play ahead of his rallies.

Mr. Trump praised his supporters’ energy and asked his team if the following day would be peaceful. “Don’t forget,” Mr. Trump told them, “these people are fired up.”

Supporters of President Donald Trump besiege the U.S. Capitol on Jan. 6.

Supporters of President Donald Trump besiege the U.S. Capitol on Jan. 6.

Photo: Jose Luis Magana/Associated Press

Within an hour of Mr. Trump’s speech the next afternoon, a mob of his supporters pressed up against the Capitol doors and police declared a riot. A piece of lumber smashed through a window at about 2 p.m. and rioters swarmed inside, where they prowled across the waxed sandstone floors beneath the iconic cast-iron dome—in search of Mr. Trump’s running mate.

Secret Service agents hustled Mr. Pence off the Senate floor and into a nearby hideaway. If the insurgents had arrived on the second-floor landing just seconds earlier, he would have been within their reach. The frenzied crowd had overrun the Capitol Police and the Metropolitan Police Department, and Mr. Pence’s safety—and that of just about everyone else in the Capitol—rested on the arrival of the National Guard. “I want them down here—and I want them down here now,” Mr. Pence firmly instructed during a call with the Pentagon.

Initially, Mr. Trump seemed to be enjoying the melee. Heartened to see his supporters fighting so vigorously on his behalf, he ignored the public and private pleas from advisers who begged him to quell the riots. Terrified Republican lawmakers called White House aides and the president’s children for help. D.C. Mayor Muriel Bowser twice personally implored Mr. Meadows to intervene. Mr. Trump didn’t call off the intruders until almost 4:30 p.m. “Go home—we love you, you’re very special,” Mr. Trump said in a social media video, but he didn’t denounce the violence.

The backlash against Mr. Trump was immediate. He was suspended from Twitter and Facebook the next day. A flood of White House officials resigned. The House impeached him on Jan. 13 for inciting an insurrection—becoming the only president to be impeached twice—in a bipartisan vote that included support from 10 Republicans. Top Republicans both inside and outside of Trump World believed that the man who had positioned himself as the party’s kingmaker—potentially for the next decade—was now finished.

But days after Mr. Trump left office, polls showed that he maintained high levels of support inside his party. House Republicans who had voted to impeach him found themselves the target of censure and primary challenges. Republican leaders made plans to visit him at Mar-a-Lago—a steady stream of supplicants bowing before their exiled king.

In March, during the first of my two visits with Mr. Trump in south Florida, I found him amid a transition. Once the leader of the free world, he was coming to terms with his ceremonial role as president of Palm Beach. He had arrived at Mar-a-Lago in January entirely unprepared for the post-presidency. “What am I going to do all day?” he asked one aide after stepping off Air Force One for the final time. He inquired whether friends blamed him for the Capitol riots. “You don’t think I wanted them to do that, do you?” he asked.

He peppered aides about whether he should run for president again, but few believed he would. There seemed to be a new melancholy to the former president. He told friends that his wife, Melania Trump, loved it at Mar-a-Lago and how she looked more beautiful than ever. He acknowledged that other factors might catch up with him, like his advanced age and obesity. “At least that’s what they say,” he’d always add about his excessive weight.

President Trump at Trump National Golf Club in Sterling, Va., Nov. 27, 2020.

President Trump at Trump National Golf Club in Sterling, Va., Nov. 27, 2020.

Photo: Tasos Katopodis/Getty Images

Slowly, he found relief in the new routine. He golfed every day and reveled in the attention during the dinner hour at the club. “Did you have the meat or the fish? Was it good?” he asked guests. He lost some weight, and a warm tone had reappeared in his face. He’d just finished golfing with PGA player Ernie Els when I arrived and took a call from Sean Hannity during our interview. Shockingly, he said he was glad to be off Twitter. His prewritten statements, now issued via emails, were “much more elegant.” “It’s really better than Twitter,” Mr. Trump told me. “I didn’t realize you can spend a lot of time on this. Now I actually have time to make phone calls, and do other things and read papers that I wouldn’t read.”

He’d reorganized his inner circle of political advisers. Donald Trump, Jr., replaced Mr. Kushner as the top family adviser. Mr. Trump became less reliant on his final campaign manager, Bill Stepien, and elevated Susie Wiles, who oversaw both Trump victories in Florida. He was in constant contact with Rep. Kevin McCarthy and Sen. Rick Scott, the Republicans in charge of the House and Senate races in 2022.

“ Trump has followed the 2024 chatter like a day trader monitoring his portfolio. ”

His advisers have pushed him to carefully cultivate his political power and delay deciding whether to run again in 2024 until after the midterms. Still, Mr. Trump has followed the chatter like a day trader monitoring his portfolio. When Ron DeSantis performed well in a straw poll of an obscure gathering of conservatives last month, Mr. Trump asked advisers whether the Florida governor would challenge him in a primary if he were to run. (The majority opinion was yes.) And he said on Fox News last week that he’d decided whether to run in 2024 but wouldn’t reveal the verdict.

When Mr. Trump and I talked, he avoided multiple queries about his plans. Instead, he redirected almost every question back to his claims of a stolen election. Our second interview was interrupted by a call from an attorney with a status update from his ongoing pursuit of fraud allegations in Arizona.

Mr. Trump’s plan, for now, is to display his political prowess by influencing the midterms. He’s already endorsed more than two dozen candidates, from congressional contests to an election for Staten Island borough president. Advisers have urged him to focus endorsements on winnable races, but he’s discarded that guidance in several instances.

He backed Kelly Tshibaka, who launched an uphill battle to unseat Alaska Sen. Lisa Murkowski, a fellow Republican who has won three terms in the state—but who voted to convict Mr. Trump on impeachment charges in February. In North Carolina, Mr. Trump repeatedly pushed his daughter-in-law, Lara Trump, to run for the open Senate seat, but she declined. He then decided—on the flight last month to Greenville, N.C., where he spoke at a state party event—to back Rep. Ted Budd in a competitive Republican primary race. The president’s announcement stunned aides and candidates, including Rep. Mark Walker, who became emotional when he learned about the endorsement while seated with his family in the audience. Mr. Trump has spoken to advisers about backing a primary challenger against Rep. Liz Cheney, who voted to impeach him, and plans to campaign against her in Wyoming next year.

Former President Trump arrives for a rally in Wellington, Ohio, June 26.

Former President Trump arrives for a rally in Wellington, Ohio, June 26.

Photo: Scott Olson/Getty Images

On June 26, Mr. Trump held his first rally since Jan. 6, drawing thousands to the Lorain County fairgrounds near Cleveland. The event was to support Max Miller, a former aide who has waged a primary challenge against Rep. Anthony Gonzalez, who supported impeachment charges. But Mr. Trump spent much of his 90-minute speech fixated on the 2020 results.

Mr. Trump’s new team could only shrug their shoulders. They, too, will give him space to process the loss, with the hope that he’ll find some measure of closure. His political future may depend on it. “He’ll never move on, but at least it won’t be half of his speech at some point,” one Trump aide said.

“We won the election twice,” Mr. Trump said in Ohio. “And it’s possible that we’ll have to win it a third time.”

Write to Michael C. Bender at Mike.Bender@wsj.com

Mr. Bender is The Wall Street Journal’s senior White House reporter. This essay is adapted from his new book, “Frankly, We Did Win This Election: The Inside Story of How Trump Lost,” which will be published by Twelve next week.