Less than a week ago, President Trump suggested that children may have to make do with fewer toys this year.

“Well, maybe the children will have two dolls instead of 30 dolls, you know?” He said those two dolls may “cost a couple of bucks more than they would normally.”

On Monday, Mattel, the U.S. toy company and maker of Barbies, said it would raise prices on U.S. toys because of Mr. Trump’s 145 percent tariffs on imports from China. Mattel, which produces 20 percent of its U.S.-sold goods there, said in its first-quarter earnings presentation that it aims to reduce that to less than 15 percent by 2026. It also said it would suspend its financial guidance for the year, citing uncertainty over trade and tariff policies.

Factories in China produce nearly 80 percent of all toys sold in the United States. Several U.S. toy companies have said they would likely raise prices because of the tariffs.

The Toy Association, a U.S. industry group representing 850 toy manufacturers, warned shortages were likely before Christmas. Its survey of 410 small businesses that make toys found that a majority said they had canceled orders, and about half said they risked going out of business within weeks or months if the tariffs remained in place.

Mattel is one of numerous companies that suspended financial forecasts for this year, including General Motors, Snap and UPS, because of Mr. Trump’s economic policies. Mattel said that given the “volatile macroeconomic environment and evolving U.S. tariff situation, it was too difficult to predict consumer spending and U.S. sales for the year.”

Zach Warring, an analyst at CFRA Research, said that Mattel could insulate itself from tariffs by selling more of its Chinese-made goods outside the United States. Mattel can also protect its margins by raising prices, but he questioned whether U.S. customers would be willing to pay more, or if toys would instead sit on shelves and ultimately need to be discounted.

Trump just unleashed on Canada in a post on Truth Social, shortly before he is set to meet with the country’s leader, Mark Carney, at the White House.

“We don’t need their Cars, we don’t need their Energy, we don’t need their Lumber, we don’t need ANYTHING they have, other than their friendship, which hopefully we will always maintain,” Trump said. “They, on the other hand, need EVERYTHING from us! The Prime Minister will be arriving shortly and that will be, most likely, my only question of consequence.”

Trump has repeatedly threatened Canada’s sovereignty in recent months, setting the stakes for a potentially contentious meeting between the two leaders.

In his post taking aim at Canada, President Trump again cited a figure he framed as a subsidy the United States gives its neighbor to the north. The number he gave, $200 billion, appears to be a reference to the United States’ trade deficit with Canada. But that is vastly inflated: Last year, the U.S. had a $63.3 billion trade deficit with Canada, according to U.S. official data. The U.S. ran a trade surplus with Canada if one excludes Canadian oil exported to America.

During a hearing this morning in a lawsuit about campus speech and whether the Trump administration can deport international students based on their support for Palestinians, Judge William G. Young is laying out a remarkable preview of his thinking. A Reagan nominee, Judge Young started by saying he came up during the Warren court, and has always believed the First Amendment protects “the right of all persons” to free speech. But he quickly added that that interpretation may have shifted under the current Supreme Court, and he was no longer certain the justices would share that view.

“I’m not clear that noncitizens have, I will call them, the full rights to free speech that a citizen has,” he said. “I’m looking for guidance.”

Kristi Noem, the Homeland Security secretary, would not give a yes-or-no answer when asked at a House committee hearing whether she believed the Constitution guaranteed due process to everyone in the U.S. “Due process is exactly what this Congress lays out,” Noem said, before Representative Lauren Underwood, Democrat of Illinois, moved on to her next question.

Noem also said her department did not have the authority to remove U.S. citizens from the country and was not doing so. The Trump administration has drawn scrutiny as American children with citizenship have been sent abroad alongside their undocumented parents.

Bessent said he did not have an updated estimate for “X-date,” the day the U.S. could default if the debt limit is not raised. But he said he would provide more information to Congress soon on that. The most recent estimate for that date is somewhere between mid-July and early October. “Just as an outfielder running for a fly ball, we are on the warning track,” he said. “When you’re on the warning track, it means the wall is not that far away.” Bessent added that the U.S. would not default and that gimmicks would not be necessary to deal with the debt limit.

Treasury Secretary Scott Bessent, testifying before a House committee, said trade deals with major U.S. trading partners could be announced as soon as this week. But there is no movement yet with China. “China we have not engaged in negotiations with as of yet,” he said.

Looking deeper into the trade numbers released earlier, it appears that the surge in imports was almost entirely due to the ingredients that pharmaceutical companies need to manufacture drugs, which Trump has been threatening to tariff. “There was far less of everything else, like toys, furniture, appliances, kitchenware, apparel, etc. imported in March than suspected, meaning there was no surge in inventories of finished consumer goods,” said Omair Sharif, president of the analysis firm Inflation Insights. That could mean store shelves will empty out sooner rather than later.

Data out this morning show that the overall U.S. trade deficit in goods and services rose sharply in March to $140.5 billion, from $123.2 billion in February. That continues a swift upward trend that we’ve seen since the November election, driven by record imports of goods, as importers try to bring in products like machinery and consumer goods in advance of tariffs.

U.S. trade deficits with Mexico, Ireland, France, India and Vietnam all hit their highest monthly levels on record in March as importers tried to get ahead of tariffs and as U.S. consumers snapped up foreign goods. The Trump administration says its tariffs are intended to eliminate bilateral trade deficits, though many economists say these deficits are not a good metric to focus on.

Just days after winning a stunning election on an anti-Trump platform, Prime Minister Mark Carney of Canada on Tuesday will meet with President Trump, who has imposed tariffs on Canada, America’s closest ally, next-door neighbor and top trading partner, and repeatedly threatened its sovereignty.

With the relationship between the two countries in tatters, the two leaders will sit down in the White House for their first face-to-face discussion, a high stakes encounter that could easily go sideways.

Mr. Trump has claimed that Canada doesn’t deserve to be independent because of its reliance on U.S. trade and defense and has spoken about making it part of the United States.

Mr. Carney was a political novice who was swept to power because Canadians saw him as a steady hand to negotiate with Mr. Trump and guide Canada through economic turmoil because of his background as a policymaker and private-sector executive.

Mr. Carney served a governor of the Bank of Canada during the 2008 global financial crisis and of the Bank of England during Brexit, establishing himself as one of the world’s most prominent central bankers.

He faces an unenviable balancing act.

Canadians who took a chance on him will expect him to push back on Mr. Trump’s belittling and threatening rhetoric against Canada, as he promised he would.

But he will also need to avoid openly antagonizing Mr. Trump in their working luncheon or in front of journalists in the Oval Office photo opportunity that will follow.

There was no firm agenda going into the meeting. On Monday, Mr. Trump said he was “not sure” what Mr. Carney wanted to discuss. Canadian officials framed the meeting as a first step in the two leaders becoming acquainted and beginning talks that would likely go on for a while.

As is often the case with Mr. Trump, a lot could come down to his chemistry with Mr. Carney, which is untested.

The two may not be a natural match. Mr. Carney is a sometimes stiff former banker, known to not suffer fools. He has — while campaigning — revealed a snappish side, as well as a bone-dry sense of humor, when pressed or cornered.

But he could earn Mr. Trump’s respect for his private-sector experience — he worked at Goldman Sachs for more than a decade and was later a boardroom leader for major companies.

“He’s a very nice man, I think,” Mr. Trump said of Mr. Carney in an interview on the NBC program, “Meet The Press” on Sunday.

The anodyne statement was an improvement on his feelings about Mr. Carney’s predecessor, Justin Trudeau. The two had a public falling out in 2018, and the relationship never recovered.

Mr. Trudeau visited Mr. Trump after his re-election in Mar-a-Lago, when he was still prime minister, to plead his country’s case against tariffs.

Mr. Trump has since said that, during that dinner, Mr. Trudeau told him Canada would be crushed if the United States imposed tariffs. While Mr. Trudeau has never confirmed this version of events, Mr. Trump has cited Mr. Trudeau’s supposed statement to claim that Canada doesn’t deserve to be a country because it is overly dependent on the United States.

He started referring to Mr. Trudeau as “Governor Trudeau” and Canada as “the 51st state.”

Despite the more respectful language regarding Mr. Carney, it was clear Mr. Trump was not backing down from his main claims about Canada.

“I’m a real estate guy at heart,” he told NBC. “When I look down at that artificial line that was drawn with a ruler many years ago — was just an artificial line, goes straight across. You don’t even realize. What a beautiful country it would be.”

On a call with Mr. Trudeau in February, Mr. Trump said he did not like the border treaty between the two nations, a claim he’s since repeated publicly, and raised doubts about the two countries’ water-sharing agreements.

The president’s statements suggest he is eyeing a renegotiation of the agreements that regulate the relationship between the two next-door neighbors, a worrying prospect for Canada, which would enter such talks as the weaker party.

“America wants our land, our resources, our water, our country,” Mr. Carney said in his acceptance speech last week. “President Trump is trying to break us so he can own us. That will never happen.”

Mr. Trump has imposed tariffs on many Canadian goods, but some goods that had been slated for tariffs have been exempted as he has changed his mind, spreading confusion.

Canada has applied retaliatory tariffs against U.S. goods, the only country to take that step besides China, although Mr. Carney has said there is a limit to this approach.

The United States, Canada and Mexico have long had a free-trade agreement, now known as U.S.M.C.A., which lays in tatters. Renegotiating a new deal is one of Mr. Carney’s goals.

“We subsidize Canada to the tune of $200 billion a year,” Mr. Trump told NBC on Sunday, citing an incorrect figure about the two countries’ trade balance. In reality, the United States last year had a $63.3 billion trade deficit with Canada, according to U.S. government data. When Canadian oil exported to the United States is excluded, America has a surplus.

Mr. Trump has complained that Canada is a laggard in military spending in NATO, which has a target for its members of committing 2 percent of economic output to defense. Mr. Carney has promised to reach that goal by the end of this decade.

And Mr. Trump has said Canadian industries like dairy and banking are unfairly protected, making access for U.S. competitors harder.

Many elements of the relationship that Mr. Trump says are unfair, were agreed on as part of the trade agreement he negotiated and signed in his first term.

Representative Alexandria Ocasio-Cortez of New York said on Monday that she would not pursue becoming the top Democrat on the House Oversight Committee, citing her party’s emphasis on seniority as an obstacle.

“It’s actually clear to me that the underlying dynamics in the caucus have not shifted with respect to seniority as much as I think would be necessary,” Ms. Ocasio-Cortez, 35, told reporters.

Ms. Ocasio-Cortez initially sought the position last year but lost in an internal contest to Representative Gerald E. Connolly of Virginia, 75. Mr. Connolly announced last week that he would step back from his duties as he faces cancer, leading younger, more progressive lawmakers to start pitching themselves for the position.

Ms. Ocasio-Cortez, who was elected in 2018, is one of the most prominent young Democrats. Her decision not to pursue the position would seem to clear the way for others in her mold to jockey for it. The Oversight Committee’s top Democrat is one of the party’s most visible opponents to the Trump administration.

But her remarks cast doubt on whether House Democrats might buck their long adherence to the seniority system, even as many members of their party clamor for generational change.

Ms. Ocasio-Cortez’s failed bid last year was seen as a setback for those in her party eager to break a long-established but unwritten rule that seniority should determine who gets prominent leadership roles, even as other younger members replaced older colleagues on some lower-profile committees.

Weeks after the internal vote, she left the Oversight Committee for a spot on the influential Energy and Commerce Committee. That move would have complicated any effort that she might have made to succeed Mr. Connolly: House Democrats’ rules allow lawmakers to lead only committees they sit on.

But Ms. Ocasio-Cortez, who has been speaking before big crowds on a tour with Senator Bernie Sanders of Vermont, is one of her party’s brightest stars. Several Democrats on the Oversight Committee said last week that they were waiting to see whether she was interested, saying that she was a skilled messenger who would make a good foil to the Trump administration.

Mr. Connolly’s position is not vacant. At a recent hearing, Representative Stephen F. Lynch of Massachusetts fulfilled his duties. Mr. Lynch, 70, has said he is interested in succeeding Mr. Connolly.

President Trump signed an executive order on Monday evening to further restrict experiments on pathogens and toxins that could make them more harmful.

For over a decade, scientists have debated the risks and benefits of so-called “gain of function” research. They’ve long tinkered with viruses and bacteria to endow them with new functions like producing insulin for people with diabetes. Some researchers have modified bird flu viruses in order to figure out which mutations might be crucial for producing pandemic strains that could spread among people.

Although such experiments may have benefits, critics have maintained that the risk of an accidentally created pandemic was not worth taking. In 2014, all federal funding was halted on experiments that could make certain viruses more dangerous. The first Trump administration lifted that ban in 2017 and instituted a new procedure to review possibly dangerous research.

The debate over gain of function research sharpened during the pandemic. Mr. Trump and other elected officials have linked such research to the origin of Covid, claiming that Chinese researchers produced the coronavirus in a lab in Wuhan. At Monday’s signing ceremony, the president raised that connection again. “I think I said that from Day 1, that it leaked out,” he said. “A scientist walked outside to have lunch with a girlfriend or was together with a lot of people.”

A number of published studies point instead to a market in Wuhan as the origin of the pandemic, contending that evidence strongly suggests that wild mammals picked up a bat coronavirus and that when the animals were sold at the market, they passed the virus to people.

American intelligence agencies are divided in their assessments. The Department of Energy and the F.B.I. have endorsed the idea that the pandemic originated in the Wuhan lab. This year, the C.I.A. said that it also favored the lab leak theory but, like the Department of Energy, had “low confidence” in that assessment.

However, the National Intelligence Council and four other intelligence bodies favored the idea that the pandemic had natural origins, according to an intelligence assessment conducted in 2021.

The scrutiny led an expert panel to develop a sweeping set of changes to how the federal government oversees potentially dangerous experiments. The Biden administration adopted the changes officially last year.

Critics at the time complained that the policy was not aggressive enough. For example, it lacked an independent regulatory agency to review research proposals.

Mr. Trump’s new executive order dismissed the Biden policy as having “insufficient levels of oversight.” It directs the Office of Science and Technology Policy to revise or replace the policy with new regulations.

The new policy would end support for gain of function research that was deemed dangerous and was conducted in countries of concern, including China. It would also impose new constraints on research within the United States. The executive order also calls for the government to develop a strategy to oversee potentially dangerous research carried out without federal funds within the United States.

A newly declassified memo released on Monday confirms that U.S. intelligence agencies rejected a key claim President Trump put forth to justify invoking a wartime statute to summarily deport Venezuelans to a prison in El Salvador.

The memo, dovetailing with intelligence findings first reported by The New York Times in March, states that spy agencies do not believe that the administration of Venezuela’s president, Nicolás Maduro, controls a criminal gang, Tren de Aragua. That determination contradicts what Mr. Trump asserted when he invoked the deportation law, the Alien Enemies Act.

“While Venezuela’s permissive environment enables TDA to operate, the Maduro regime probably does not have a policy of cooperating with TDA and is not directing TDA movement to and operations in the United States,” the memo said.

The memo’s release further undercuts the Trump administration’s rationale for using the Alien Enemies Act and calls into question its forceful criticism of the ensuing coverage. After The Times published its article, the Justice Department opened a criminal investigation and portrayed the reporting as misleading and harmful. The administration doubled down a month later after similar coverage in The Washington Post, citing the disclosures in both articles as a reason to relax limits on leak investigations.

The document, known as a “sense of the community” memo, was released by the Office of the Director of National Intelligence in response to a Freedom of Information Act request by the Freedom of the Press Foundation. The foundation provided a copy to The Times.

Lauren Harper, the Daniel Ellsberg chair on government secrecy for the foundation, said the memo was at odds with the administration’s portrayal of its contents as a dire threat to public safety.

The government “almost immediately declassified the same information in response to a FOIA request,” she said.

Ms. Harper continued: “The declassification proves that the material should have been public from the start — not used as an excuse to suppress sharing information with the press.”

But administration officials continued to defend Mr. Trump’s policy.

“It is outrageous that as President Trump and his administration work hard every day to make America safe by deporting these violent criminals, some in the media remain intent on twisting and manipulating intelligence assessments to undermine the president’s agenda to keep the American people safe,” Tulsi Gabbard, the director of national intelligence, said in a statement.

A Justice Department official said in a brief statement Tuesday morning that the gang had terrorized Americans. The White House did not respond to requests for comment.

Until Mr. Trump invoked it in mid-March, the Alien Enemies Act, an 18th-century law, had been used only three times in American history, all during declared wars. It says the government may summarily remove citizens of a country that is at war with the United States or otherwise engaged in an invasion of or predatory incursion into U.S. territory.

Immediately afterward, the administration sent planeloads of Venezuelans to a notorious high-security prison in El Salvador with no due process. Courts have since blocked further transfers under the proclamation. Citing evidence that some of the men sent there were likely not gang members, the American Civil Liberties Union has asked a judge to order the Trump administration to bring back the Venezuelans for normal immigration hearings.

On its face, the Alien Enemies Act appears to require a link to a foreign government. Mr. Trump declared that Tren de Aragua had committed crimes to destabilize the United States “at the direction, clandestine or otherwise, of the Maduro regime in Venezuela.”

But The Times reported days later that the intelligence community had circulated findings on Feb. 26 that reached the opposite conclusion. The shared assessment was that Venezuela’s government and the gang were adversaries, even though some corrupt Venezuelan officials had ties to some gang members. It also said the gang lacked centralized command-and-control and was too disorganized to carry out any instructions.

The Times also reported that only the F.B.I. partly dissented and thought there was some kind of link, but it was based on information the other agencies — like the C.I.A. and the N.S.A. — thought was not credible.

The Trump administration asked the National Intelligence Council, made up of senior analysts and national security policy experts who report to Ms. Gabbard, to take another look at the available evidence.

On April 7, it produced the memo released on Monday. The Washington Post reported on the memo, which remained classified, later that month, further angering the administration.

Now in public view, the memo said the intelligence community based its conclusion on a series of factors. Venezuelan security forces have arrested Tren de Aragua members and have “periodically engaged in armed confrontations with TDA, resulting in the killing of some TDA members,” the memo said, showing that the government treats the gang as a threat.

While there is evidence that some “mid- to low-level Venezuelan officials probably profit from TDA’s illicit activities,” the memo said, the gang’s decentralized makeup would make it “logistically challenging” for the organization as a whole to act at the behest of the government.

The memo also shed additional light on the F.B.I.’s partial dissent.

It said that while F.B.I. analysts agreed with the other agencies’ overall assessment, they also thought that “some Venezuelan government officials facilitate TDA members’ migration from Venezuela to the United States and use members as proxies in Chile, Colombia, Ecuador, Peru, and the United States to advance what they see as the Maduro regime’s goal of destabilizing governments and undermining public safety in these countries.”

The F.B.I. based its view on “people detained for involvement in criminal activity in the United States or for entering the country illegally.” But “most” of the intelligence community “judges that intelligence indicating that regime leaders are directing or enabling TDA migration to the United States is not credible,” the memo said.

In examining the available evidence, the National Intelligence Council evaluated whether detainees “could credibly have access to the information reported” and whether they had offered details that could be corroborated about support the Maduro government had purportedly provided the gang in exchange for following its directions.

While portions of this section were redacted, the memo signaled skepticism. The detainees’ legal troubles, it said, could “motivate them to make false allegations about their ties to the Venezuelan regime in an effort to deflect responsibility for their crimes and to lessen any punishment by providing exculpatory or otherwise ‘valuable’ information to U.S. prosecutors.”

In late March, the memo noted, Chilean officials told the International Criminal Court that they suspected that the murder of a Venezuelan man in Chile last year was carried out by “a cell or group linked to the Tren de Aragua that was politically motivated” and originated from an order by Venezuela’s government. The Maduro administration denied that accusation.

But the memo also said other parts of the intelligence community had not observed or collected evidence of communications or funding flows showing government officials providing directions to leaders of the gang, even though such a relationship would likely require “extensive” such interactions.

Judges so far have stayed away from second-guessing the truth of Mr. Trump’s factual claims in deploying the Alien Enemies Act.

The day after the initial Times article, Todd Blanche, a former defense lawyer for Mr. Trump who is now deputy attorney general, announced that the Justice Department had opened a criminal leak investigation.

In a statement, he criticized the article, saying the information in it was classified but also “inaccurate.” But the declassified memo supports The Times’s reporting.

In an interview on Megyn Kelly’s podcast last week, Ms. Gabbard said that the reporting on the intelligence community’s conclusions was “being investigated.” Leakers had “selectively and intentionally left out the most important thing,” she added, pointing to the F.B.I.’s belief that the Maduro government was supporting the gang’s activities in the United States.

But the articles in both The Times and The Post discussed the F.B.I.’s contrary view.

Last month, Attorney General Pam Bondi wrote in a memo that she would roll back protections for press freedoms in leak investigations, citing the Times and Post articles as damaging examples of leaks of classified information.

Defense Secretary Pete Hegseth ordered a 20 percent reduction of four-star officers — the military’s senior ranks — continuing the wide swath of job reductions and firings that have marked his three months at the helm of the Pentagon.

In a memo on Monday, Mr. Hegseth also ordered a 10 percent reduction of overall general-level officers in the military, and a 20 percent cut of four-star positions in the National Guard.

“Through these measures, we will uphold our position as the most lethal fighting force in the world, achieving peace through strength and ensuring greater efficiency, innovation and preparedness for achieving any challenge that lies ahead,” he said.

Mr. Hegseth has already fired a raft of military leaders, many of them people of color and women. He fired the Black chairman of the Joint Chiefs of Staff, Gen. Charles Q. Brown Jr.; the first woman to command the Navy, Admiral Lisa Franchetti; and the U.S. military’s representative to the NATO military committee, Vice Admiral Shoshana Chatfield.

Mr. Hegseth is fighting calls for his own firing after disclosing on Signal, a commercial chat app, the flight sequencing for U.S. strikes against Iranian-backed Houthis in Yemen.

He has made targeting what he has called a “woke” agenda at the Pentagon one of the signatures of his tenure. Last week he boasted on social media that he had “proudly” canceled a program encouraging more women to take roles in national security.

In his memo on Monday laying out the cuts, Mr. Hegseth, a former Fox News weekend anchor, said that “the Department of Defense is committed to ensuring the lethality of U.S. Military Forces to deter threats and, when necessary, achieve a decisive victory.”

He added: “A critical step in this process is removing redundant force structure to optimize and streamline leadership by reducing excess general and flag officer positions.”

There are about 800 general-level officers in the military. At the most senior, four-star level, there are 44.

It was unclear how Mr. Hegseth planned to cut the positions. Because general officers serve at the pleasure of the president, they can sometimes be easier to fire than lower-ranked service members.

The Trump administration on Monday sought to force Harvard University back to the negotiating table by informing the nation’s oldest and wealthiest college that it would not be eligible for any new federal grants.

That decision was relayed in a contentious letter to Alan M. Garber, the president of Harvard, from Linda McMahon, the education secretary, who blasted the school for “disastrous mismanagement.”

“This letter is to inform you that Harvard should no longer seek grants from the federal government, since none will be provided,” Ms. McMahon wrote in the letter.

It was the first significant response from the administration since Harvard sued to challenge the government’s decision to cut billions of dollars in research funding after the university defied demands for intrusive oversight.

An Education Department official who briefed reporters about the letter before it was released said that Harvard’s eligibility for research grants depended on its ability to first address concerns about antisemitism on campus, policies that consider a student’s race, and complaints from the administration that the university has abandoned its pursuit of “academic excellence” while employing relatively few conservative faculty members.

In a statement on Monday night, a Harvard spokesperson said the letter showed the administration “doubling down on demands that would impose unprecedented and improper control over Harvard University and would have chilling implications for higher education.”

The statement suggested it would be illegal to withhold funds in the manner Ms. McMahon described.

“Harvard will continue to comply with the law, promote and encourage respect for viewpoint diversity, and combat antisemitism in our community,” the statement said. “Harvard will also continue to defend against illegal government overreach aimed at stifling research and innovation that make Americans safer and more secure.”

The statement maintained Harvard’s toughened posture toward the administration and came days after the university said there was “no legal basis” behind President Trump’s threat to revoke its tax-exempt status.

Ms. McMahon’s three-page letter, which deployed the use of all-capital letters to emphasize words, overflowed with familiar grievances from Mr. Trump and other conservative critics of Harvard. The missive said the college had “made a mockery of this country’s higher education system.” It accused the university of “ugly racism,” mentioned “humiliating plagiarism scandals” and lashed out at the university’s leadership.

“At its best, a university should fulfill the highest ideals of our nation, and enlighten the thousands of hopeful students who walk through its magnificent gates,” Ms. McMahon wrote. “But Harvard has betrayed its ideal.”

Beyond the tone of Ms. McMahon’s letter, the federal government’s threat on Monday suggested that the government was altering its tactics against elite universities. The administration’s first blows to top schools stripped existing grants from universities — a dramatic step but one that also raised the prospect of court challenges, especially given the haste of the funding cuts.

Harvard built its pending lawsuit against the government around both the First Amendment and the Administrative Procedure Act, which tightly restricts how federal agencies work, after the administration suspended more than $2 billion in funding with little warning.

But university leaders across the country have been privately fearing a more orderly attack on research funding that would be harder, though not necessarily impossible, to contest. A blanket ban on grant funding against Harvard, or any other specific school, could still invite litigation — but a deliberate process, some higher education officials believe, would be more difficult to resist in court.

Since returning to the White House, Mr. Trump has led an assault on the nation’s elite universities, which his administration sees as hostile to conservatives and intent on perpetuating liberalism.

No university in the country, though, is at greater odds with the government than Harvard.

Last month, the Trump administration sent Harvard a list of demands that included auditing professors for plagiarism, reporting to the federal government any international students accused of misconduct, and appointing an outside overseer to make sure that academic departments were “viewpoint diverse.”

The administration has said the letter containing those demands was sent by mistake, but the fight has continued to escalate. Harvard sued the administration, accusing the government of trying to wield “unprecedented and improper control.” Dr. Garber has said the consequences of the government’s actions would be “severe and long lasting.”

Under a system that has been a part of American life since around World War II, Harvard, like other top research institutions, relies on federal money to support many of its projects.

In the 2024 fiscal year, federally sponsored research dollars accounted for about 11 percent of Harvard’s revenues, or roughly $687 million. And although Harvard’s endowment is worth more than $53 billion, much of that money is restricted, limiting how the university may spend it. A lasting freeze on new grants could unleash financial havoc for Harvard, which has already been making contingency plans and looking to raise money through the bond markets.

Ms. McMahon made a point of mentioning Harvard’s wealth in her letter on Monday, describing the university’s endowment as a “head start” for an era without federal grant money.

Much of the endowment, she told Dr. Garber, was “made possible by the fact that you are living within the walls of, and benefiting from, the prosperity secured by the United States of America and its free-market system you teach your students to despise.”