As the incoming president finishes the oath of office at the Capitol, the former president’s military aide lugging a briefcase containing the country’s nuclear war plans — known as the “football” — hands it over to a new uniformed aide, who takes up position near the just-inaugurated commander in chief.

Unnoticed to most, the president’s power to wage war in an instant has changed hands.

But this year’s football handoff will be long-distance for the first time — one of many crucial and cherished transition traditions that President Trump plans to upend in his final hours in office.

By refusing to meet face to face with President-elect Joe Biden or attend the swearing-in Wednesday at the Capitol building that his supporters stormed on Jan. 6, Trump is attempting one last departing snub of Biden after repeatedly failing to overturn the November election results.

“It’s changing the entire tenor of the transition, which is supposed to be symbolic to the country and the world,” said Andrew Card, a former White House chief of staff who ran the transition when President George H.W. Bush lost reelection to Bill Clinton in 1992. “It will be missed.”

Trump’s refusal to formally concede his loss is taxing inauguration planners, White House staff and career officials already tasked with organizing a challenging transition amid sky-high security fears and a pandemic that has forced much of the usual pageantry to be made virtual.

A jury-rigged inauguration has been planned without the exiting president. Meanwhile, Trump has ordered his own ceremonies, in a bid to upstage Biden and to send a message that he isn’t yielding, at least not in person.

No other president has done more to obstruct a smooth transfer of power than Trump, said Timothy A. Naftali, a presidential historian at New York University. “We’ve had disgruntled outgoing presidents,” he said. “But we’ve never had a president who actively sought to obstruct a transition. And that involved inciting an insurrection.”

Biden will be staying at Blair House, the government guesthouse a few hundred yards from the White House.

He planned to begin the day by attending church, inviting Republican leaders in Congress to join him in a symbolic show of restoring unity.

But Trump has not invited Biden to the mansion for the usual bittersweet greeting by the departing incumbent of the incoming president and first lady on the steps of the White House. Nor will there be the usual morning coffee in the Blue Room. Those events are typically brief and awkward, usually not lasting much longer than five minutes.

“I remember a lot of plastic smiles and the small talk, and in some cases, it’s really small,” said Robert F. Goodwin, who was an aide to four presidents. As the deputy director of the Bush-Cheney inaugural committee in 2001, he oversaw preparations after a contentious, drawn-out election.

The images of those welcome rituals are important in showing America’s peaceful transfer of power before the symbolic drive together to the Capitol for the swearing-in, he said. But Trump isn’t emotionally equipped to fulfill these particular presidential duties, Goodwin said.

He recalled being in the White House grand foyer when President Ford welcomed Jimmy Carter, when the first President Bush welcomed Clinton and when, eight years later, President Clinton welcomed George W. Bush.

“I don’t think we’re ever going to be going back to the way inaugurations were,” Goodwin said, recalling the morning of the younger Bush’s first inauguration. “I was on the West Front of the Capitol at 5 a.m., and I could hear bass drums and helicopters and people coming on the grounds to celebrate. It was really special. I think it would be unfortunate to not be able to celebrate a new president like that again.”

Trump is also reportedly mulling whether to end the recent tradition of the exiting White House occupant leaving a personal note for his successor in the Oval Office.

The elder Bush, still nursing his wounded pride after losing to Clinton, wrote one of the most memorable of these letters, addressing his replacement, “Dear Bill,” and telling him, “Your success now is our country’s success. I am rooting hard for you.”

Obama left his own note for Trump, presciently reminding him that they were both “ just temporary occupants of this office” and must be “guardians” of the country’s “democratic institutions and traditions.”

On Wednesday, Biden will be sworn in by Chief Justice John G. Roberts Jr. on the Capitol’s West Front around noon, then deliver his inaugural address and review military troops — all customary in a traditional inauguration. Instead of a parade down Pennsylvania Avenue with cheering spectators, though, Biden and Vice President Kamala Harris, along with their spouses, will have a military escort to the heavily protected White House.

By then, Trump will have been gone from the mansion for at least four hours.

At most inaugurations, outgoing executives have stayed in the background on their final day. Once the swearing-in is over, they usually board a helicopter at the Capitol with family and one or two close aides, take a wistful aerial tour over Washington, and head to Joint Base Andrews outside the capital for a small, sometimes tearful departure.

When Obama took office in 2009, he stood on the Capitol steps with Biden and smiled and waved as Bush boarded a Marine helicopter to head for Andrews.

“I think Trump will regret not going to the Capitol,” said Card, noting that the helicopter ride over the city was always a moving moment for a former president to reflect on his time in the White House. “It was very emotional with George W. Bush.”

Trump is standing that tradition on its head, leaving the White House early Wednesday with First Lady Melania Trump and heading to Andrews for what he is hoping will resemble one of his campaign rallies, augmented with military pomp, according to an official familiar with the plans.

He will then fly to Mar-a-Lago in West Palm Beach, Fla., aboard Air Force One, the official designation of the presidential aircraft that Trump treasures, and that remains at his service until the moment Biden is sworn in.

Trump’s military aide is likely to accompany him to Florida, always nearby and carrying the football in the unlikely event that Trump needs to order a nuclear strike in the final hours of his presidency.

Stephen Schwartz, a senior fellow at the Bulletin of the Atomic Scientists, said he was aware of only one instance in which a president still in office departed the White House without the football: When President Nixon resigned in 1974, his military aide did not join him on the helicopter to Andrews although Nixon would officially be president for nearly two more hours.

Schwartz said he would be watching closely Wednesday to see whether Trump’s military aide joins him on the trip to Florida.

If tradition holds, Biden will have been visited at Blair House on Tuesday by top uniformed leaders from the Pentagon, who will brief him on the plan to hand over the football the following day — procedures Biden is familiar with from his time as vice president. Former officials who have heard the top-secret briefing on the procedures for ordering a nuclear strike describe it as one of the most chilling moments of the transfer of power.

“It’s a very sobering thing,” Card said. “I can remember them saying, ‘If you give the authorization and say it should be done, you should have every confidence it will happen.’”

The handoff will probably occur remotely, said an official familiar with the planning. Another military aide carrying a matching briefcase with new nuclear codes meant to work after the swearing-in will shadow Biden as he makes his way to the Capitol. When Biden is officially president, the aide will step forward and assure Biden he will never be far away.

Trump’s aide in Florida will quickly leave his side.

Soon after the handover, one last ritual that most are hoping never becomes tradition will play out: Within hours or days of Biden taking over, the Senate is likely to convene an impeachment trial of his predecessor.