Republican officials across Washington are acquiescing to and amplifying President Trump’s baseless claim that he won the 2020 presidential election — raising the risk of undermining the public’s faith in the vote and, by obstructing President-elect Joe Biden’s transition, potentially imperiling national security.

In recent days, Trump’s appointees and allies have alighted on a strategy to support his refusal to admit defeat and initiate a peaceful transfer of power. Instead, they are nurturing the president’s ego by indulging his delusions about the vote count and fueling conspiracy theories that the election is being stolen from him.

The White House has instructed government agencies to block cooperation with the Biden transition team — including the General Services Administration, whose Trump-appointed administrator, Emily Murphy, has refused to sign paperwork that releases millions in preallocated dollars to fund the transition and gives Biden’s team access to agency officials and information.

These unprecedented moves risk further eroding public trust in democratic institutions, and they have potentially dangerous consequences. The nation is at its most vulnerable state during the transition period between administrations, according to experts in governance and public service, who worry that the Trump administration is threatening national security by denying Biden the necessary resources, intelligence and other information to conduct his transition.

“We live in an incredibly dangerous world that moves very fast, so having a president truly ready to go on Day One is fundamental to our safety,” said Max Stier, president of the Partnership for Public Service. “There’s no more complicated or important organization on the planet in history than the U.S. government, and taking it over is a massive undertaking.”

The already daunting task is made more challenging by the coronavirus pandemic, he added. “It’s a sprint in the best of circumstances, made even harder by having to do it virtually,” Stier said. “They don’t need these extra problems.”

Almost since Election Day, an increasing number of Trump advisers and allies have privately conceded that they do not think the president will win reelection, even if he pursues all legal options at his disposal. They have said they are simply trying to give Trump — a notoriously sore loser who has long fashioned himself a victim of nefarious forces seeking to undermine him — the time to come to grips with his loss, knowing he is likely to refuse to ever officially acknowledge the election results.

But the delay in a peaceful transition of power — whatever the justification — has potentially devastating effects, not just for Biden but for the nation.

“They all know he lost, and they are lying about it to protect his little feelings. It’s insane,” said Tim Miller, a former Republican strategist who led one of several outside groups working to elect Biden. “They’re all playing pretend because Donald wants a participation trophy, and there are real human consequences — not just to our democracy, but threats to individuals and their lives.”

Trump’s false claims undermining the legitimacy of the election are being echoed not only by those in the upper echelons of his administration but also by senior members of the Republican establishment.

Asked on Tuesday whether the State Department was cooperating with the Biden team to ensure a smooth transition of power, Secretary of State Mike Pompeo responded as if Trump had been reelected.

“There will be a smooth transition to a second Trump administration,” said a smiling Pompeo, leaving it unclear whether his answer was intended as a joke.

Sen. Roy Blunt of Missouri — a member of Senate Republican leadership who, as co-chairman of the Joint Congressional Committee on Inaugural Ceremonies, has responsibility for ensuring a peaceful transition — similarly called into question the results of the election.

“You know, the president wasn’t defeated by huge numbers,” Blunt said Tuesday. “In fact, he may not have been defeated at all.”

Blunt’s comments represented a remarkable shift from just two days earlier, when he said on ABC’s “This Week” that it was “unlikely” the Trump team’s legal efforts would ultimately produce a Trump victory.

Other Republican lawmakers have joined the chorus, including Sen. Marco Rubio of Florida, who posted a video Tuesday on social media in which he said: “President Trump is well within his legal rights to pursue all these things under these laws now. Now, for those in the media who are angry that Republicans won’t just take their word for it that Biden won, I think you need some self-awareness.”

Trump badly trails Biden, who leads by nearly 5 million votes and has cemented 279 electoral votes — nine more than needed to win — compared with Trump at 214. Biden also has leads in Arizona and Georgia, which would bring him to 306 electoral votes. Any path to victory through legal outcomes is deeply unlikely — and a far cry from the contested 2000 election, which came down to 537 votes in Florida.

Speaking to reporters on Tuesday in Wilmington, Del., Biden made clear he was determined to move ahead with his administration planning, saying he could name Cabinet members as soon as this month, and calling Trump’s continued insistence that he won “an embarrassment, quite frankly.”

“How can I say this tactfully?” Biden said before plowing ahead. “I think it will not help the president’s legacy.”

Michael D’Antonio, a Trump biographer, said that Trump’s party has clearly decided to mollify its temperamental leader.

“It seems like the Republicans have opted for the coddling approach to parenting a bratty child, and maybe when the child is as powerful as the president there’s no other option,” D’Antonio said. “But, really, the child needs a timeout.”

Senate Majority Leader Mitch McConnell (R-Ky.) sought to dismiss concerns over Trump’s continued efforts to challenge the election results by saying there was “no reason for alarm.”

Attorney General William P. Barr set the law enforcement community on edge Monday when he gave federal prosecutors approval to pursue allegations of “vote tabulation irregularities,” despite there being no evidence of widespread fraud as alleged by Trump and his aides. The move prompted the head of the Justice Department’s Election Crimes Branch to step down in protest.

“It’s meant to damage the confidence of voters that their vote can count, and to get people to believe that no matter what they do, they’re not going to be able to remove Trump from power, that he is stronger than the will of the people,” said Ruth Ben-Ghiat, a historian of authoritarian regimes and author of the new book “Strongmen: Mussolini to the Present.”

She added: “The aim of not allowing Biden to start the transition is to sabotage as much as possible his presidency, and this is typical of authoritarian leaders and the idea that if they have to leave, they’re going to drag the whole edifice down with them.”

Every major news organization on Saturday declared Biden the winner based on preliminary vote totals, as has been done in nearly every modern U.S. election, including in 2016 when Trump won the electoral college by a similar margin. Biden and Vice President-elect Kamala D. Harris claimed victory, and this week, some foreign presidents and prime ministers have called Biden to congratulate him, as is customary.

Only a few GOP lawmakers have publicly acknowledged Biden’s win, however, including Sen. Mitt Romney of Utah, the lone Republican to vote to convict Trump during his impeachment trial this year.

On Saturday, Romney tweeted shortly after the race was called: “Ann and I extend our congratulations to President-elect Joe Biden and Vice President-elect Kamala Harris. We know both of them as people of good will and admirable character. We pray that God may bless them in the days and years ahead.”

Stuart Stevens, a Trump critic who was a top adviser on Romney’s unsuccessful 2012 presidential bid, said he is disgusted by the unwillingness of so many elected Republicans to publicly accept the election results.

“Every one of these Republicans is lying,” said Stevens, a senior adviser on the Lincoln Project, a group of anti-Trump Republicans. “They’re sitting there a few miles from Arlington [National] Cemetery, where people died for democracy, and they can’t get their communications shop to issue a two-sentence statement congratulating Biden.”

He added: “It’s racist, and it’s cowardly, and it’s going to be defining for a lot of these people.”

Sen. Christopher A. Coons (D-Del.), who is close to Biden, said Tuesday on CNN that many Republican senators accept the reality, even if they won’t admit it.

“They call me to say, you know, ‘Congratulations, please convey my well wishes to the president-elect, but I can’t say that publicly yet,’ ” Coons said, though he did not name anyone.

Paul C. Light, a professor of public service at New York University who has closely studied presidential transitions over the years, warned that Trump’s refusal to concede and the willingness of Republicans to go along is “planting the seeds of a breakdown” in the federal government.

“I keep thinking of that big baby [Trump] balloon and thinking, ‘Is that what’s going on?’ ” Light said. “What’s the endgame here? Do we just have to soothe the president’s ego until he finally says, ‘Okay, I can go home now’?”