Among the affected authors was Elaine Weiss, whose new book, “Spell Freedom: The Underground Schools that Built the Civil Rights Movement,” tells the story of the Highlander Folk School. In the 1950s, it began organizing “citizenship schools” where Black southerners were trained to pass the Jim Crow-era literacy tests designed to prevent them from voting.

In an interview, Ms. Weiss said the event had been arranged in November. But on Thursday afternoon, she said, her publicist at Simon & Schuster informed her that she had been told it could not go forward because the library, which was facing staff cuts, now needs approval from Washington for all programming. (Simon & Schuster declined to comment.)

Ms. Weiss said that she did not know whether the event had been called off because of the subject of her book. But she called the sudden cancellation “chilling.”

“The idea that a program about a book about democracy has to be approved by someone in Washington was and should be for everyone very scary,” she said. “The book is about voting rights, and about using education as a liberating tool.”

The other speakers whose events were canceled include Mike Tidwell, the author of “The Lost Trees of Willow Avenue: A Story of Climate and Hope on One American Street,” and Brian Goldstone, the author of “There Is No Place for Us,” about five “working homeless” families in Atlanta. By Friday evening, information about all three events had been removed from the library’s website.

In a statement, Crown, Mr. Goldstone’s publisher, said that the local bookseller helping organize the event contacted it on Feb. 19 “to let us know that the Carter Library would now need to seek approval from the National Archives for all programs, even those already scheduled.” The next day, the publisher was told it would be moved to a different location.

Multiple inquiries sent to several officials at the Carter library received no response.

The press office of the National Archives in Washington declined to answer directly whether it had discussed the events with the Carter Library. But in a statement, it said that it “entrusts” leadership at each presidential library to make programming decisions.

“Programs and events must always advance and uphold NARA’s core mission: to preserve the records of the United States and make them available to the public,” the statement said. “On this issue, leadership at the Carter Presidential Library is empowered to make their own decisions about scheduling events and programs.”

The cancellations at the Carter Library come amid broader turmoil at the National Archives, as President Trump works to remake the federal government through budget cuts and seeks retribution against perceived foes.

On Feb. 7, President Trump, who has tangled with the archives over his reluctance to return classified documents after leaving office in 2021, abruptly fired Colleen J. Shogan, the national archivist. (Shogan, a former official at the Library of Congress and the White House Historical Association, was appointed by former President Joseph R. Biden Jr.)

Mr. Trump named Secretary of State Marco Rubio as acting archivist, and announced on Feb. 16 that Jim Byron, the chief executive of the Richard Nixon Foundation, a private group connected with the Nixon presidential library in California, would manage the archives “on a day-to-day basis” until a permanent archivist is appointed.

Earlier this month, the John F. Kennedy Library and Museum in Boston abruptly closed its doors to the public in the middle of the day, after what a member of the Kennedy family claimed were staff cuts demanded by Elon Musk’s so-called Department of Government Efficiency. (The library reopened the next day, and the archives did not provide any explanation for the brief closure.)

Some planned events at the Carter Library appear to be unaffected. An event on Feb. 26 featuring the legal analyst Jeffrey Toobin, author of a new book on presidential pardons, was still scheduled. Other events still listed on its website include an event with the African-American artist Lonnie Holley.

Ms. Weiss’s event will now be held at the Georgia Center for the Book, a private nonprofit affiliated with the Library of Congress. She said it was ironic that an event about the fight for equal voting rights would be canceled at the Carter Library, an institution dedicated to the legacy of “a man who stood up for democracy around the world.”

“We are being told that we all have to tell ‘patriotic’ stories about American history,” she said. “To me, this is the most patriotic story imaginable.”

“Trump wants to make sure that the Joint Chiefs of Staff are 100 percent loyal to him,” Representative Adam Smith, Democrat of Washington State and the ranking member of the House Armed Services Committee, said in an interview. “I don’t think there is any question that is why he did it. There is no argument that General Brown isn’t an incredibly capable leader.”

General Brown’s dismissal took effect immediately. Pentagon officials said on Saturday that Adm. Christopher W. Grady, the vice chairman of the Joint Chiefs, is now acting chairman until the Senate confirms a permanent replacement.

Retired military officers argued that General Brown did not deserve to be fired and was the kind of war-fighting officer that President Trump said he wanted to lead the armed forces.

Mark Montgomery, a retired rear admiral and a senior fellow at the Foundation for the Defense of Democracy, said General Brown was a “proven war-fighter.”

“His dismissal is a loss to the military,” Admiral Montgomery said. “Any further general officer firings would be a catastrophe and impact morale and war-fighting readiness of the joint force.”

Senator Jack Reed, Democrat of Rhode Island and the ranking member of the Armed Services Committee, issued an unusually strongly worded statement condemning General Brown’s ouster and warning that the White House and Mr. Hegseth could push out other officers.

“This appears to be part of a broader, premeditated campaign by President Trump and Secretary Hegseth to purge talented officers for politically charged reasons, which would undermine the professionalism of our military and send a chilling message through the ranks,” Mr. Reed said.

National Security Leaders for America, a bipartisan volunteer organization of former military and civilian leaders, released a statement saying that the group condemned the removal of senior military officers without just cause, and echoed the concerns about politicizing the military. “Removing experienced leaders with meritorious records weakens the force and emboldens America’s enemies,” the statement said.

Representative Smith said Congress had set up the term of the chairman of the Joint Chiefs to extend across presidential administrations to preserve institutional knowledge. The purge of the Joint Chiefs, he said, will make the military less ready.

The firings, Mr. Smith said, were about ensuring there would be no checks on the power of Mr. Trump and Elon Musk, who is leading efforts to shrink the government.

“It is about control and power. That is the whole thing about what Musk and Trump are doing,” Mr. Smith said. “What Musk and Trump want more than anything is to be able to do what they want to do, whenever they want to do it, without any check on that power.”

Other Democrats joined in. Senator Richard Blumenthal of Connecticut said the firings were based on politics, not merit, and that “our adversaries in Russia and China are celebrating.” Senator Adam B. Schiff of California said that amid larger efforts by the Trump administration across the government, “the purge of people of stature and independence goes on.” And Senator Mark Kelly of Arizona said the firings were “disrespectful to the service and sacrifice of everyone who’s put their life on the line for our country.”

Senator Elissa Slotkin, Democrat of Michigan and a former senior Pentagon official in the Obama administration, said Mr. Trump’s purge “should send a shiver down the spine of any American who cares about an apolitical military.”

“For most of our history, leaders from both parties have largely kept their political activities separate from how they handle the military,” Ms. Slotkin said in a social media message. “But not this president and not this SecDef. No matter how they try and spin it, they have brought their political retribution to the very war-fighters they claim to care about. And we are no safer for it.”

Throughout the Biden administration, Republicans railed against what they saw as the Pentagon’s bending to liberal policy priorities, accusing the military of putting too much effort into promoting diversity.

But many Republicans respected General Brown. After his ouster, Republican lawmakers who support Mr. Trump were circumspect. Some praised General Brown’s service, but none criticized the president’s action directly.

While Senator Roger Wicker of Mississippi, the chairman of the Armed Services Committee, said he was confident Mr. Trump would choose a “qualified and capable successor,” he offered no specific praise of General Cain, and said General Brown had served honorably.

John R. Bolton, a national security adviser to Mr. Trump in his first term who himself became a target of the president’s retribution, said the firing had been a mistake and would serve to politicize the American armed forces.

“This is the retribution campaign at work,” Mr. Bolton said in a telephone interview on Saturday. “To presume military officers will fail to carry out lawful orders presumes they’re politicized, and that’s very harmful to the military. I’m worried about the long-term consequences for the military.”

Mr. Smith said he was also worried about the long-term consequences. He said that up and down the chain of command, officers would be less willing to speak up and that that would degrade the quality of the advice the military gives its civilian leadership.

“Trump has made it clear that if you don’t do what Trump likes, you are going to get fired,” Mr. Smith said. “You’re going to have a bunch of ‘yes men’ around there who aren’t going to use their best judgment or their intelligence.”

Greg Jaffe in Washington contributed reporting.

But the math that could back up those checks is marred with accounting errors, incorrect assumptions, outdated data and other mistakes, according to a New York Times analysis of all the contracts listed. While the DOGE team has surely cut some number of billions of dollars, its slapdash accounting adds to a pattern of recklessness by the group, which has recently gained access to sensitive government payment systems.

Some contracts the group claims credit for were double- or triple-counted. Another initially contained an error that inflated the totals by billions of dollars. In at least one instance, the group claimed an entire contract had been canceled when only part of the work had been halted. In others, contracts the group said it had closed were actually ended under the Biden administration.

The canceled contracts listed on the website make up a small part of the $55 billion total that the group estimated it had found so far. It was not possible to independently verify that number or other totals on the site with the evidence provided. A senior White House official described how the office made its calculations on individual contracts, but did not respond to numerous questions about other aspects of the group’s accounting. But it is clear that every dollar the website claims credit for is not necessarily a dollar the federal government would have spent — or one that can now be returned to the public.

The mistakes touched a wide range of contracts — some worth hundreds of millions of dollars and others worth just a few thousand.

David Reid, an environmental scientist in Michigan, was surprised to learn his contract studying invasive species in the St. Lawrence Seaway was included on the list. “That contract wasn’t canceled by DOGE or anyone else,” he said. The contract expired on Dec. 31 and he decided to retire and not renew it, he said. “If they took credit for canceling the contract, they’re lying.”

The group claimed $25,000 in savings from his project.

Though the group’s public messaging has focused on the efficiency in its name, most of the canceled contracts appear to relate to other administration priorities, such as the shuttering of U.S.A.I.D. and the elimination of government programs on diversity, equity and inclusion. The cancellations listed come disproportionately from businesses run by women and people from minority groups.

The numerous mistakes, according to people familiar with the complex world of government contracting, suggest that Mr. Musk’s team of outsiders, charged by the president with cutting spending, don’t fully understand it.

The numbers have been cheered by Mr. Musk’s online followers, who are eager for the new administration to reduce wasteful spending funded by taxpayer dollars. But even contracting insiders who share that goal — and who believe that the government systems that track spending badly need repair — were increasingly skeptical of the effort this week.

Amber Hart, the co-founder of a research and advisory firm, the Pulse, that specializes in federal contracting, said it’s simply not possible to create a real-time accounting of contract savings with the data the team has used — as DOGE has promised on its website.

“There’s no way for them to make it possible unless they completely overhaul the way the data is reported — which would be awesome,” she said. “I would absolutely love for them to break that. They’re breaking the wrong things.”

Why it’s hard to say how much is really being saved

The 1,125 contracts the initiative’s website listed as of Friday night make up about 20 percent of the project’s overall spending cuts, the website said, although The Times’s analysis could not reconcile those numbers. The website says the remaining dollars come from efforts like reducing the federal work force, but provides no data or specific estimates.

The dollar values posted for each contract derive from data in a central tracking system for government contracts with outside vendors.

Here’s an example of how Mr. Musk’s team made one such calculation, according to the White House official’s description of the process:

But such savings estimates can be too high, several experts said, for a few reasons.

For one, the spending figure may undercount what the government has already spent, because the data in the federal contracting system can be several months out of date.

The numbers shown above also don’t account for additional termination costs the government will have to pay to close these contracts, making them a “meaningless metric,” said Steven Schooner, a professor of government procurement law at George Washington University Law School.

Contractors will have to wind down staff, close offices, terminate leases and offload equipment — a normally lengthy process that will now be rushed and potentially litigated. (The White House official did not address this issue but said that the estimate was conservative because it did not include any administrative savings from managing the canceled contracts.)

The group also claims unrealistic estimates from several special kinds of umbrella contracts. When the government expects many different offices may want ongoing orders of the same general product or service — say, I.T. — it creates an overall contracting mechanism with a set ceiling under which several pre-vetted vendors can compete for individual orders. Each of those individual orders represents money the government has committed to spend. But the ceiling on the whole umbrella doesn’t.

“It’s not real money,” said Kelly Saldana, who spent nearly two decades working at U.S.A.I.D., including as the director of its office of health systems. If one of these larger contracts has a ceiling of $100 million and there’s only one $10 million order under it, the remaining $90 million isn’t savings or money that could be spent elsewhere.

“Nobody ever does that math,” Ms. Saldana said, describing the kind of math Mr. Musk’s group appears to have done.

A report by CBS News this week found another type of error involving this kind of contract: The group had triple-counted the $655 million maximum value of one contract for U.S.A.I.D. with numerous sub-contracts.

In another case, DOGE claimed $232 million in savings on a contract providing information technology support to the Social Security Administration. But The Intercept reported that only a sliver of the contract was canceled — a program to let users mark their gender as “X” — bringing the actual savings closer to $560,000.

Other anomalies on the site this week were apparent even without much knowledge of the apparatus of government contracting.

Do you have a confidential news tip about canceled contracts? Submit it here: nytimes.com/tips

The Times reported Tuesday about an $8 million contract for technical support services at the Immigration and Customs Enforcement agency that had been mistakenly entered into the database at a value of $8 billion, close to the size of the entire agency’s budget. This error alone made up nearly half of the combined value of all listed contract cuts.

The “wall of receipts” also lists hundreds of cases in which — even by the website’s own accounting — the changes saved taxpayers nothing. In one contract, the Securities and Exchange Commission had agreed to spend $10 million for a five-year subscription to the legal-research site Westlaw. But the savings are listed as $0. The S.E.C.’s contract expired in March 2024.

Far from ‘fully transparent’

The “wall of receipts” page acknowledges that it may contain some inaccuracies. “Over time, the website will improve and the updates will converge to real-time,” it says. It also promises to share data in a “digestible and fully transparent manner with clear assumptions.”

So far, the site has not been fully transparent about the data it includes or about the changes it makes.

Around the same time news organizations published articles on major inaccuracies, the “wall of receipts” website was updated to correct the errors without changing the “last updated” date.

The contract list itself also represents only a small share of the group’s claimed overall savings. The website says the effort has saved $55 billion in total, but has provided no details on its “wall of receipts” for the bulk of that money. The top-line number also did not change this week, even after the site fixed errors that inflated the savings of individual grants.

One place where the office has more regularly communicated with the public is on the social media platform X, owned by Mr. Musk. But it has repeated some of the same kinds of errors there. In one post about the $8 billion mistake, the group claimed it had “always used the correct $8M in its calculations,” despite its updates to its site.

On Wednesday, the DOGE account reposted a message on X from the Treasury Department, saying that the I.R.S. had “rescinded a previously planned $1.9B contract” and done so “in connection” to the group’s work — describing a canceled contract that wasn’t yet on the DOGE.gov “wall of receipts.”

The account added a screenshot showing a $1.9 billion purchasing agreement — another one of those umbrella contracts — with an unnamed vendor, now marked “terminate for convenience.”

A code in the screenshot identified the vendor as Centennial Technologies, a company in Northern Virginia. But that company said its agreement had actually been canceled in the fall, during the Biden administration.

“Nothing changed now,” Mani Allu, the company’s chief executive, said in an email. He said that the slow-moving contracts database had not been updated to show the cancellation until this month, making the change appear new.

Representatives from the Treasury Department and the consumer bureau did not respond to requests for comment.

Russell Vought, the Office of Management and Budget director, was named the acting director of the consumer bureau’ two weeks ago. He immediately began shutting down what he called “a woke & weaponized agency,” ordering its headquarters closed and its staff to halt all work. Nearly 200 employees — those who were probationary hires or who worked on fixed-term contracts — were fired, and those who remained were forbidden from entering the agency’s offices.

The consumer bureau cannot be officially abolished without action from Congress, which created the agency in the aftermath of the Great Recession to regulate consumer products like mortgages, auto loans, credit cards and bank accounts. The bureau has twice survived Supreme Court cases that aimed to eliminate it.

But firing nearly all the bureau’s staff — as Mr. Vought intends, according to litigation in federal court in Washington that is aimed at curtailing his actions — and eliminating its physical premises would functionally be a death knell.

Employees will be assigned a 15-minute window in which they can return to the agency’s headquarters to pick up their personal effects, according to two people who were told of the shutdown plan.

Among the many open questions are what will happen to the agency’s records, some of which are subject to “litigation holds” and cannot legally be destroyed. A plan to transfer papers to a storage facility is being developed, but several employees said they worried about what would happen to the vast array of agency records held by cloud software providers. If the contracts with those providers are canceled, irreplaceable data risks being deleted.

Judge Amy Berman Jackson, of the U.S. Court for the District of Columbia, issued an order last week that temporarily prevents the consumer bureau from deleting any agency data, which includes records located on the agency’s “premises, on physical media, on a cloud server, or otherwise.”

That order will last until Judge Jackson rules on a request for a restraining order sought by lawyers representing the consumer bureau’s staff union and other parties. A hearing on that request is scheduled for March 3.

While Judge Jackson’s order has paused some of the unwinding of the agency’s staff and infrastructure, the physical dismantling of its premise has begun. Workers this week removed the signage on its Washington headquarters.

In all, six Pentagon officials were fired, including Adm. Lisa Franchetti, the first woman to lead the Navy; Gen. James Slife, the vice chief of the Air Force; and the top lawyers for the Army, Navy and Air Force.

The decision to fire General Brown, which Mr. Trump announced in a message on Truth Social, reflects the president’s insistence that the military’s leadership is too mired in diversity issues, has lost sight of its role as a combat force to defend the country and is out of step with his “America First” movement.

Joint Chiefs chairmen traditionally remain in place as administrations change, regardless of the president’s political party. But current White House and Pentagon officials said they wanted to appoint their own top leaders.

In a statement, Defense Secretary Pete Hegseth thanked Admiral Franchetti and General Slife “for their service and dedication to our country” and requested nominations for their replacements.

Mr. Hegseth did not say why he was firing the judge advocates general. But in his Senate confirmation hearing last month, he criticized military lawyers for placing needless legal restrictions on soldiers in battle — putting “his or her own priorities in front of the war fighters, their promotions, their medals, in front of having the backs of those making the tough calls on the front lines.”

Mr. Hegseth has previously said General Brown should be fired because of his “woke” focus on diversity, equity and inclusion programs in the military.

“First of all, you’ve got to fire the chairman of the Joint Chiefs,” Mr. Hegseth said in an appearance on the “Shawn Ryan Show” in November. He added that any general involved with D.E.I. efforts should be fired. “Either you’re in for warfighting, and that’s it,” he said. “That’s the only litmus test we care about.”

On Mr. Hegseth’s first day at the Pentagon, however, he stood next to General Brown, who became chairman in October 2023, and said he looked forward to working with him.

But it soon became clear that General Brown had not been welcomed into Mr. Trump’s inner circle. He has not been invited to key meetings with the president, officials said.

It was a significant reversal for Mr. Trump from 2020, when he nominated General Brown to be the Air Force’s chief of staff. At the time, the president noted the historic significance of his decision to appoint the “first-ever African American military service chief,” writing on social media that the general was “a Patriot and Great Leader.”

General Brown had told aides repeatedly that he would not resign. On Friday, he was in El Paso and at the southwestern border, reviewing the military’s latest mission of helping to carry out Mr. Trump’s immigration directives.

Mr. Trump did not say in his post why he was firing General Brown. “He is a fine gentleman and an outstanding leader, and I wish a great future for him and his family,” the president wrote.

General Brown found out he was being removed when Mr. Hegseth telephoned him at his hotel in El Paso on Friday evening, a military official said.

General Caine retired with three stars, as a lieutenant general. By statute, anyone picked to be the chairman of the Joint Chiefs of Staff is supposed to have served as a combatant commander, as the vice chairman of the Joint Chiefs of Staff or as the top uniformed officer of the Army, Navy, Air Force, Marine Corps or Space Force.

It was unclear whether General Caine would need a congressional waiver; a congressional aide said the president had some latitude to choose whom he wanted and that exceptions could be made for national security reasons.

Regardless of whether he requires one, he will need to be confirmed by the Senate.

In the past, the position has been viewed as one that, like the military itself, spans administrations.

In his message on Truth Social, Mr. Trump said he was honored to be nominating “Air Force Lieutenant General Dan ‘Razin’ Caine to be the next Chairman of the Joint Chiefs of Staff,” calling him “an accomplished pilot, national security expert, successful entrepreneur, and a ‘warfighter’ with significant interagency and special operations experience.”

In recent years, Mr. Trump has publicly lauded General Caine for telling him that the Islamic State could be defeated far more quickly than his advisers had suggested. The details of the story, which could not be independently verified, have shifted over time. In one version, Mr. Trump said the general claimed it would take a week to defeat the group; in another, he said four weeks.

Mr. Trump has also claimed that General Caine, during their meeting in Iraq in December 2018, donned a “Make America Great Again” hat, in defiance of military guidelines that active-duty troop should not wear political paraphernalia. General Caine has told aides that he has never worn a MAGA hat.

In his post on Truth Social on Friday, Mr. Trump again praised General Caine’s counterterrorism skills.

“During my first term, Razin was instrumental in the complete annihilation of the ISIS caliphate,” Mr. Trump said. “It was done in record setting time, a matter of weeks. Many so-called military ‘geniuses’ said it would take years to defeat ISIS. General Caine, on the other hand, said it could be done quickly, and he delivered.”

In fact, by December 2018 when Mr. Trump visited General Caine in Iraq, other senior U.S. officials were saying that the final defeat of the last remnants of the Islamic State was only months away, although rebuilding Iraq would probably take years.

Mr. Trump has fixated on the position of the Joint Chiefs chairman since 2019, when he picked Gen. Mark A. Milley, General Brown’s predecessor, a decision the president came to bitterly regret.

Mr. Trump has complained in particular about General Milley’s calls to his Chinese counterpart during the waning weeks of the president’s first term. In a post on social media, Mr. Trump called the act “so egregious that, in times gone by, the punishment would have been DEATH!”

Having a loyalist as his top military adviser is now paramount to Mr. Trump, aides say.

The dismissal of General Brown comes amid growing tumult at the Pentagon, the largest federal agency with three million employees, including 1.3 million service members. Mr. Hegseth has ordered senior military and Defense Department officials to draw up plans to cut 8 percent from the military budget over each of the next five years, officials said on Wednesday.

In a memo issued on Tuesday, Mr. Hegseth said a number of branches in the military and the Pentagon should turn in budget-cutting proposals by Monday, two officials said. The memo listed 17 exceptions to the proposed cuts, including military operations at the southern border.

The decision to replace General Brown with General Caine was made over the past two weeks and was tightly held within a small group of senior administration officials, according to two people with knowledge of the deliberations.

While Mr. Hegseth was in Europe last week, General Caine met with Vice President JD Vance and then with Mr. Trump. Mr. Hegseth and General Caine spoke several times, and Mr. Hegseth advocated his appointment, one of the people said.

While reports of lists of senior general and admirals targeted for dismissal have circulated on Capitol Hill for weeks, administration officials said most senior House and Senate leaders were not consulted before Mr. Trump’s decision to relieve General Brown.

In a statement on Friday night, Senator Roger Wicker, a Mississippi Republican who heads the Armed Services Committee — the panel that approves all military nominations — praised General Brown, but made no mention of General Caine, who has not yet been officially nominated.

“I thank Chairman Brown for his decades of honorable service to our nation,” Mr. Wicker said in a statement. “I am confident Secretary Hegseth and President Trump will select a qualified and capable successor for the critical position of chairman of the Joint Chiefs of Staff.”

Senator Jack Reed, the top Democrat on the Armed Services Committee, was sharply critical of the move. “Firing uniformed leaders as a type of political loyalty test, or for reasons relating to diversity and gender that have nothing to do with performance, erodes the trust and professionalism that our service members require to achieve their missions,” he said in a statement.

Even some of Mr. Hegseth’s staunchest supporters in Congress have warned that a purge in the senior ranks of the Pentagon could cause morale to plunge.

“There’s been a lot of talk about firing ‘woke’ generals,” Senator Kevin Cramer, Republican of North Dakota, said last month at Mr. Hegseth’s Senate confirmation hearing. “I would say give those men and women a chance under new leadership.”

Most recent Joint Chiefs chairmen have served four years, with a president nominating a successor months before the incumbent chairman steps down. In his first term, Mr. Trump hinted in late 2018 that General Milley would be his choice to succeed Gen. Joseph F. Dunford Jr. nearly a year before General Dunford’s term ended.

Because General Caine is retired, he would have to be called back to active duty for the Senate to hold hearings on his nomination. Only one retired officer has been called back from retirement to serve as chairman: Gen. Maxwell D. Taylor in 1962 by President John F. Kennedy.

It was unclear whether General Brown would remain chairman until his successor was confirmed by the Senate, or whether Adm. Christopher W. Grady, the vice chairman, would serve as the acting chairman.

Mr. Trump has now fired four four-star officers in the past month. Within 24 hours of his second inauguration, the president fired Adm. Linda L. Fagan, the first female officer to serve as the commandant of the Coast Guard.

John Ismay contributed reporting.

The department has more than 945,000 civilian employees. Defense Secretary Pete Hegseth has said 17 specific missions, such as military operations at the southwestern border, would be exempt from the 8 percent cuts in the defense budget he has ordered for each of the next five years.

Senior Pentagon supervisors were told this week to expect the department to fire about 55,000 civilian workers worldwide, part of a push by President Trump and Elon Musk to drastically reduce the size of the federal work force.

The coming dismissals announced on Friday appear to be the first tranche, and target the easiest employees to fire. Workers on probation do not receive the same protections that many other federal employees have. Probationary periods tend to last a year but can be longer for certain positions.

Mr. Selnick’s statement said that the department would institute a hiring freeze while officials conducted “further analysis of our personnel needs.”

“It is simply not in the public interest to retain individuals whose contributions are not mission-critical,” he said.

Some Defense Department supervisors have criticized the looming personnel cuts as a hasty, ill-conceived move that could damage the department’s future.

The Postal Service is managed by a bipartisan board of governors — appointed to fixed terms by the president and confirmed by the Senate. Of the nine governors on the board, no more than five of the nine may belong to the same political party, and the group comes together to elect the agency’s leader, the postmaster general.

Mr. Trump confirmed his interest in the merger in remarks at the swearing-in ceremony for Howard Lutnick, the new commerce secretary, on Friday. Mr. Trump said that he intended to keep the Postal Service “a very similar way” but that he was considering a merger or possibly downsizing the agency.

“Whether it is a merger,” Mr. Trump said, “or just using some of the very talented people that we have elsewhere so it does not lose so much — it is losing a tremendous amount of money.”

A recent report by the Postal Service said that it had “recorded $87 billion in financial losses over the last 14 years and failed to meet service standards.” The report also noted the service’s struggles during the pandemic, when a dramatic increase in package deliveries “further stressed an already misaligned and outdated mail network.” The Government Accountability Office, a watchdog agency, has labeled the Postal Service as a “high risk” program vulnerable to waste, fraud and abuse.

The Postal Service, which was once a Cabinet-level department of the government, was reorganized into an independent agency under President Richard Nixon. The Postal Reorganization Act of 1970 established the board of governors as a way to insulate the agency from political pressure while making decisions on postal rates, appointments and salaries. Unions representing postal workers had carried out widespread strikes that year calling for pay increases.

The Postal Service has also been affected by the president’s sweeping agenda on tariffs. The agency had initially halted deliveries of packages from mainland China and Hong Kong after an order by President Trump in January ended duty-free handling of many smaller parcels — but quickly reversed its decision as the widespread ramifications of such a move became apparent.

On Friday, Mr. Trump criticized the Postal Service for its recent financial troubles, suggesting that the agency was inefficient and a drain on the budget.

“We want to have a post office that works well and doesn’t lose massive amounts of money,” he said.

The judge found that the group that brought the lawsuit — an association representing foreign service workers — had not demonstrated that its members faced irreparable injury so far and that it was unlikely to win its case, citing a precedent brought up in other cases suggesting that Congress had established other ways of handling employment disputes by federal workers.

The Trump administration has proposed placing nearly the entire global work force of the agency on administrative leave while simultaneously canceling a raft of its contracts and imposing a freeze on nearly all foreign aid spending.

The American Foreign Service Association, which brought the lawsuit on behalf of its members, had argued that the plan was carried out dangerously, potentially stranding overseas workers by locking them out of communications systems. It argued that what initially appeared to be a “mandatory recall notice,” requiring overseas workers to return to the United States within 30 days, also risked harming their families and children who had settled into lives abroad.

Judge Nichols found that the risk of any immediately disruptive action appeared to have abated after a declaration by Pete Marocco, a Trump appointee in charge of foreign aid.

Mr. Marocco told the court that employees in high-risk areas overseas had not been cut off from security resources, and that the administrative leave had followed protocols to protect workers while conducting a review of whether their roles were essential. Mr. Marocco’s sworn statement added that employees were only required to make “a voluntary decision about their desire to return to the United States within 30 days,” and that the agency would consider case-by-case exceptions.

While Judge Nichols said the original restraining order was based on concerns about the safety of aid workers stationed overseas, the immediate danger that led him to issue that order had passed, and that “initial assertions of harm were overstated.”

“Several subsequent submissions by the government persuade the Court that the risk posed to USAID employees who are placed on administrative leave while stationed abroad — if there is any — is far more minimal than it initially appeared,” he wrote.

After Judge Nichols’s original order, the agency reinstated all employees who had been placed on leave and restored their access to email and security notices, according to Mr. Marocco’s declaration.

The decision to dissolve the restraining order came as judges in other cases have also sought to balance the interests of federal workers ensnared in upheaval at their agencies with President Trump’s authority to reshape federal agencies to align with his political agenda.

Lawyers for the government have consistently argued that ultimately, firing large numbers of federal workers is within the president’s power, and that Mr. Trump has directed his appointees to downsize their staff in programs he considers harmful or counter to American interests. But the chaotic atmosphere in which that has unfolded, with associates of Elon Musk pushing rapid disruption and officials learning of dramatic changes with little time to prepare, has led to several lawsuits like the one before Judge Nichols.

While Judge Nichols acknowledged that “harsh consequences” could ensue with the restraining order lifted, including the resumption of personnel changes and an agencywide review to determine whether positions would be eliminated. But he wrote that the government had made a compelling case that the pauses and reviews were part of a legitimate broader agenda.

“According to the government, interfering with this ‘pencils down’ approach would prevent it from auditing USAID’s operations in the manner necessary to ensure the agency is acting in the national (and perhaps global) interest,” he wrote.

Tom Yazdgerdi, president of the American Foreign Service Association, said in a statement following the ruling that the decision imperiled some of the country’s proudest foreign assistance work.

“This decision is a setback in our fight to protect our members from efforts that threaten to dismantle USAID, but it does not change the importance of their mission — advancing U.S. interests and delivering lifesaving assistance worldwide,” he said.

Judge Nichols described the agency’s plan as keeping with Mr. Trump’s vision, which he said clearly disputed the value of most foreign aid work, and sought to broadly rein in foreign assistance, in part by reducing the agency’s footprint abroad and at home.

“Where one side claims that U.S.A.I.D.’s operations are essential to human flourishing and the other side claims they are presently at odds with it, it simply is not possible for the court to conclude, as a matter of law or equity, that the public interest favors or disfavors an injunction,” he wrote.

At least 3,000 additional people were fired from the U.S. Forest Service, which often works in concert with the parks. And thousands more seasonal workers were questioning if they would have jobs, despite a memo from the U.S. Department of the Interior, which oversees national parks, approving 7,700 temporary positions, slightly more than usual. The park service usually operates with about 20,000 total employees, including approximately 7,000 seasonal workers.

The turmoil comes just as visitors are planning their spring break and summer travel to national parks. With more than 325 million annual visitors, the parks have been struggling to meet the demand: The total number of full-time National Park Service employees dropped 15 percent from 2011 to 2022, according to figures the agency provided to Congress in 2023. Many worry that the new cuts will harm the visitor experience across some 85 million acres at 433 sites.

“If you’ve planned your bucket list trip to a national park, you may have to take into consideration that you won’t have the full experience and reschedule for next year in the hopes it gets better,” said Kristen Brengel, senior vice president for government affairs at the National Parks Conservation Association, a nonpartisan organization.

Parks around the country were already feeling the effects. When Spencer Glenn, 39, from Seattle, called the Carlsbad Caverns visitor center this week to inquire why the park’s ranger-led cave tours had been canceled, he said, the ranger told him “that because of the current federal guidelines, the national park had to fire half of its staff.”

At the Grand Canyon, a depleted staff of fee collectors resulted in lost revenue for the park over the weekend, and because of a lack of staffing at Florissant Fossil Beds National Monument in Colorado, the park announced it would be closed on Mondays and Tuesdays.

Companies that operate within the parks are also trying to understand the impact. Xanterra Travel Collection operates concessions in numerous parks, including properties like the Old Faithful Inn in Yellowstone, El Tovar Hotel at the Grand Canyon and Lake McDonald Lodge at Glacier. Andrew Heltzel, the company’s chief commercial officer, said in a telephone interview that its operations are continuing to run as planned. “We remain in close contact with the National Park Service and will provide updates promptly,” Mr. Heltzel added.

It was not clear how the cuts might affect Recreation.gov, a website that allows visitors to reserve campsites and timed-entry ticket for popular parks. A spokesman from the U.S.D.A., which administers the platform, said only that the department’s new head, Brooke Rollins, supported the effort to cut costs.

Alyssa Ravasio, the founder of the campsite booking platform Hipcamp, which allows users to find sites on private land as well as check availability at national parks through Recreation.gov, said the company was still trying to figure out what the cuts might mean for users. She recommended that visitors stay informed by signing up for email and social media updates from the parks and regional public land offices.

The impact on Yellowstone

At 2.2 million acres, Yellowstone is about the size of Rhode Island and Delaware combined. Seasonal park workers help manage and service its five park entrances, nearly 1,000 miles of backcountry trails, seven park-operated campgrounds with 450 campsites, 52 picnic areas, and 11 visitor centers, museums and contact stations.

Yellowstone has approximately 300 permanent employees, but typically hires 200 or more seasonal workers. Yellowstone managers usually aim to fill those seasonal spots by mid-March so they are ready when the park opens to auto traffic starting in mid-April. The federal hiring process includes lengthy background checks, and some workers require specialized training on everything from grizzly bear safety to first aid to backcountry horse packing.

Even a seasonal job like emptying trash cans is critical at Yellowstone, where garbage must be collected daily from scores of receptacles across the park, lest they become a food source for grizzlies and other wildlife.

Arianna Knight, 29, of Bozeman, Mont., the wilderness trails supervisor for the Yellowstone District of the Custer Gallatin National Forest, was let go on Feb. 14 along with more than 30 other Custer Gallatin employees. Ms. Knight said she and two workers under her supervision typically cleared 4,000 downed trees and logs from hundreds of miles of trails each year, often hiking and using hand tools for a week at a time in wilderness areas, where federal law prohibits motorized vehicles and mechanized tools like chain saws.

Now those trails won’t be cleared, Ms. Knight said, adding, “People are going to suffer.”

Will there be search-and-rescue staffing?

Others worry about safety in the parks. According to a 2023 National Park Service study, the rate of heat-related illnesses and deaths in the parks may double in the coming years as temperatures rise because of climate change. In the summer of 2023, N.P.S. reported its highest number of heat-related illnesses, citing deaths at Big Bend National Park in Texas and at Death Valley National Park, where temperatures reached 129 degrees Fahrenheit. Last summer, triple-digit heat led to deaths in the Grand Canyon and at Canyonlands National Park in Utah.

“We don’t know exactly how many search-and-rescue personnel were laid off,” said Ms. Brengel, of the parks conservation association, “so maybe this isn’t the year to do a treacherous hike through a national park.”

When asked about how the Trump administration’s cuts will affect safety, an N.P.S. spokeswoman said, “The National Park Service is working closely with the Office of Personnel Management to ensure we are prioritizing fiscal responsibility for the American people. As always, N.P.S. will continue to provide critical services and deliver excellent customer service.”

While it may seem as if the cuts will mean fewer people trampling through the parks, allowing ecosystems to regenerate, some fear the opposite: that less oversight and control over huge crowds may damage the parks for seasons to come.

Adam Auerbach, 32, a former park ranger at Rocky Mountain National Park, said visitor numbers at the park has been climbing consistently for decades, to more than four million in 2023 from 2.6 million in 1990. The park has had to institute a timed-entry permit system to control the numbers.

With the new cuts, he said, “There will be fewer rangers on the ground to enforce regulations and fewer public educators to help the public even understand the regulations and the reasons for them in the first place.”

Evelynn Escobar, the founder and executive director of Hike Clerb, which aims to increase diversity among hikers, said in an Instagram post to her 38,000 followers that they should pitch in to prevent any possible harm.

“I need us to think, ‘what would a ranger do?’” she wrote. “If you see trash on the ground, pick it up and put it in the trash. You see wildlife on the trail, keep a safe distance and don’t interact with them. You see restoration areas marked ‘in progress,’ you’re going to stay off those lands.”

Follow New York Times Travel on Instagram and sign up for our Travel Dispatch newsletter to get expert tips on traveling smarter and inspiration for your next vacation. Dreaming up a future getaway or just armchair traveling? Check out our 52 Places to Go in 2025.