As conservatives fought against cancel culture on college campuses, they developed a particular fondness for the First Amendment. It was un-American, they argued, to punish someone for exercising their right to speak freely.

Today, however, many of those same conservatives, now in power in state and federal government, are behind a growing crackdown on political expression at universities, in ways that try to sidestep the Constitution’s free-speech guarantees.

President Trump and Republican lawmakers say that new laws and policies are necessary to protect students from harmful and objectionable content, to prevent harassment and to discourage conformity.

To that end, Mr. Trump has threatened to withhold hundreds of millions of federal dollars from universities because they moved too slowly to quell protests that left many Jewish students feeling threatened. And Republicans in state legislatures have drafted sweeping prohibitions against classroom “indoctrination” and the display of certain L.G.B.T.Q. symbols. They have also demanded the removal of art they consider inappropriate.

In some cases, the Trump administration has said existing federal law already gives the president all the power he needs to act. When Mr. Trump said he would deport student activists, for example, he claimed to be acting in the interest of American foreign policy.

Tellingly, administration officials have said they are not bound by the First Amendment when it comes to noncitizens.

“This is not about free speech,” said Secretary of State Marco Rubio. “This is about people that don’t have a right to be in the United States to begin with. No one has a right to a student visa. No one has a right to a green card.”

Critics of this broad approach, including some on the right, say Republicans are being just as heavy-handed and censorious as they claimed the left was toward them.

“That makes the situation so much worse,” said Greg Lukianoff, chief executive of the Foundation for Individual Rights and Expression, a free-speech group that often represents moderates and conservatives who claim they’ve been retaliated against for their political views.

“Now we have all this federal pressure and pressure from state governments — sometimes really direct and clear, and sometimes hazy and confusing,” he said, adding, “There’s a lot fewer people who care about the nonpartisan defense of free speech now.”

For many First Amendment experts and academics, the new laws and orders reveal an especially insidious threat: Public officials who are willing to marshal the power of the state against people whose views they dislike.

“A number of people in elected office have gotten extraordinarily comfortable with the idea that they should use that office to control the spread of ideas and information,” said Jonathan Friedman, a managing director at PEN America, a free speech advocacy group.

“And at a fundamental level, that’s what makes all of this so dangerous,” Mr. Friedman added.

While the federal government’s role in some aspects of education is fairly limited, it does hold powerful tools that the Trump administration has been eager to use. It can launch civil rights investigations, for instance, or withhold research grants.

States, which provide more funding for public schools and universities than the federal government does, have greater leverage and control.

Legislation approved last month by the Ohio State Senate sets parameters for the discussion of any “controversial belief or policy” at state universities — including climate change, electoral politics, abortion and immigration. The bill demands that faculty members “shall not seek to indoctrinate any social, political, or religious point of view.”

Sponsors say its purpose is to “allow students to exercise their right to free speech without threat of reprisal.” If it becomes law, universities would also be required to post all undergraduate course syllabuses online, along with the professor’s contact information and professional qualifications.

Many states have taken aim at diversity, equity and inclusion programs in university hiring and admissions. But Republicans in Arizona are going further, by trying to remove the subject entirely from the classroom. The State Senate approved a bill this month that would deny funding to any public college or university that teaches about contemporary American society through the academic framework of concepts including “critical theory, whiteness, systemic racism, institutional racism, antiracism, microaggressions.”

A bill awaiting the governor’s signature in Utah would outlaw pride flags at public schools and on government property.

In some cases, Republicans have directly interfered with campus activities. Students at the University of North Texas took down a pro-Palestinian art exhibit last month after a Republican lawmaker complained that it referred to genocide in Hebrew.

At Texas A&M University, officials banned drag performances on campus, saying it was “inconsistent” with the university’s values to host events that “involve biological males dressing in women’s clothing.”

The American education system has long been a target for conservatives, many of whom see it as hostile to their values. In the last few years, the country’s most explosive political and cultural clashes — over Covid policy, racial inequality, gender identity, immigration, Gaza — have played out with intensity on campus quads, at school board meetings and in the classroom.

Disruptive student protests have been an animating issue for Mr. Trump. In 2017, he suggested revoking funding from the University of California, Berkeley, after the university canceled an appearance by the professional right-wing provocateur Milo Yiannopoulos.

Today, Mr. Trump — who declared in his recent address to Congress that he had “brought back free speech” — continues to antagonize academia, but this time he is using the power of the presidency.

After his administration announced that it was canceling $400 million in funding for Columbia University, accusing it of failing to protect students and faculty members from “antisemitic violence and harassment,” legal scholars called the move an existential threat to academic freedom.

“Never has the government brought such leverage against an institution of higher education,” said Lee C. Bollinger, the former president of Columbia University.

Some conservatives said this kind of action is overdue and unsurprising.

“When you take federal funds, you agree to abide by all kinds of rules,” said Ilya Shapiro, director of constitutional studies at the conservative Manhattan Institute. Universities agree, for instance, to abide by certain accounting standards and anti-discrimination policies.

Those rules are not always enforced consistently, Mr. Shapiro said. Nor is the Trump administration “exactly being legally precise” in a lot of what it has done, he added.

“But part of this vibe shift that elected Trump is wanting law and order in a lot of ways,” Mr. Shapiro said. “And that includes on college campuses.”

The arrest earlier this month of Mahmoud Khalil, a green-card holder who was born in Syria and studied at Columbia, was one of the most aggressive moves yet by the Trump administration in its effort to punish pro-Palestinian demonstrators. Mr. Khalil served as a spokesman for a student group that embraces hard-line anti-Israel rhetoric and says it supports liberation for Palestinians “by any means necessary, including armed resistance.”

In announcing the arrest, the Department of Homeland Security accused Mr. Khalil of aligning himself with Hamas, a designated terrorist organization. Voicing support for such causes is not, however, a crime, and the Supreme Court has declared all manner of hateful speech to be protected by the First Amendment, including cheering the deaths of soldiers at their funerals and, in certain cases, cross burnings.

“It can’t be a crime — or even a civil offense — simply to hold and express heinous views,” said Ann Coulter, the conservative firebrand whose college speeches have been the targets of protesters and have sometimes been threatened with violence.

Ms. Coulter, an immigration hard-liner who acknowledged that she had rarely heard of a deportation that she didn’t support, said the president would be setting a terrible precedent by making protected speech — as offensive as it may be — a reason for deporting a legal green card holder like Mr. Khalil.

But Eugene Volokh, a senior fellow at the Hoover Institution at Stanford, said that the law is not always clear when the speech of noncitizens is at issue. And he said that Mr. Trump’s attempts to punish noncitizens seemed consistent in many ways with powers that Congress had already given presidents.

Does that mean that Mr. Khalil can be deported for protesting, which is a constitutionally protected act? “The only honest answer,” Mr. Volokh said, “is we don’t know.”

Conservatives have tested the scope of the First Amendment in other ways recently. Ed Martin, the Trump-appointed interim U.S. attorney for the District of Columbia, told the dean of Georgetown University Law Center that he had begun an “inquiry” into the school’s teaching and promotion of diversity, equity and inclusion — and insisted that he would not hire students from any university that continues to offer such programs.

In response, the school’s dean, William Treanor, wrote in a letter that the First Amendment guarantees Georgetown, a private, Catholic institution, “its abilities to determine, on academic grounds, who may teach, what to teach, and how to teach it.”

“This is a bedrock principle of constitutional law,” Mr. Treanor continued, “recognized not only by the courts, but by the administration in which you serve.”

President Trump signed an executive order on Thursday that directs the federal Department of Education to come up with a plan for its own demise.

Only Congress can abolish a Cabinet-level agency, and it is not clear whether Mr. Trump has the votes in Congress to do so. But he has already begun to dismantle the department, firing about half of its staff, gutting its respected education-research arm, and vastly narrowing the focus of its civil rights division, which works to protect students from discrimination.

Mr. Trump’s long history of attacking the Department of Education represents a revival of a Reagan-era Republican talking point. It has unified Democrats in fiery opposition. But is shuttering the department possible? And if not, how has Mr. Trump begun to use the agency to achieve his policy goals?

What does the department do?

The Education Department was founded in 1979. Its main job is distributing money to college students through grants and loans. It also sends federal money to K-12 schools, targeted toward low-income and disabled students, and enforces anti-discrimination laws.

The money for schools has been set aside by Congress and is unlikely to be affected by Mr. Trump’s executive order. But oversight of the funds could be reduced and moved to other federal agencies.

Those federal dollars account for only about 10 percent of K-12 school funding nationwide. While Mr. Trump has said he wants to return power over education to the states, states and school districts already control K-12 education, which is mostly paid for with state and local tax dollars. The federal department does not control local learning standards or reading lists.

The agency does play a big role in funding and disseminating research on education, but those efforts have been significantly scaled back by the Trump administration.

It also administers tests that track whether American students are learning and how they compare with their peers in other states and countries. It is unclear whether those tests will continue to be delivered, given drastic reductions in the staff and funding necessary to manage them.

Still, closing the department would not likely have much of an immediate effect on how schools and colleges operate. The Trump administration has discussed tapping the Treasury Department to disburse student loans and grants, for instance, and Health and Human Services to administer funding for students with disabilities.

Can the Department of Education actually be closed?

Any effort to fully eliminate the department would have to go through Congress. Republican members would most likely hear opposition from superintendents, college presidents and other education leaders in their districts; schools in Republican regions rely on federal aid from the agency, just as schools in Democratic regions do.

“They are going to run into opposition,” said Jon Valant, an education expert at the Brookings Institution. “They have a laser-thin majority and a filibuster to confront in the Senate.”

Even if Congressional Republicans stuck together to support closing the agency, Dr. Valant predicted their constituents would protest, given the department’s role in distributing money from popular programs like Pell grants, which pay for college tuition, and I.D.E.A., which provides support to students with disabilities.

“It’s a very hard sell,” he said. “And I am very skeptical that is where this administration wants to spend its political capital.”

It’s worth noting that the attempt to abolish the agency is part of a larger conservative agenda to roll back the federal role in education and direct more money toward private-school vouchers and home-schooling. Trump allies have ambitions to cut the primary federal funding stream to K-12 schools, known as Title I — although doing that, too, would most likely require action from Congress.

How much power does the department have?

Even as Mr. Trump has vowed to close the department, he has begun to use the agency’s powers.

In January, the agency announced an investigation into Denver Public Schools for converting a girls’ bathroom into an all-gender facility. It is also investigating a series of conferences for students of color in the Ithaca, N.Y., public schools, and has created an “End D.E.I.” web page, encouraging individuals to report instances of “divisive ideologies and indoctrination” in schools.

In addition, Mr. Trump’s executive order on “ending radical indoctrination in K-12 schooling” directs the department to develop and disseminate “patriotic” learning materials.

It is unclear how much those orders will change practices in classrooms, given its small role in K-12 education.

The agency does issue regulations on how civil rights laws apply to various groups of students, including disabled students, L.G.B.T.Q. students, racial minorities and girls. One of the administration’s favored strategies is to argue that when schools allow transgender students to use the bathrooms or play on the sports teams of their choice, it is a violation of girls’ rights under Title IX, a law that protects students from sex discrimination.

Mr. Trump has shown less interest in other elements of civil rights law. He has fired government lawyers who investigate schools that fail to provide equal access and services to children with disabilities, for example.

Currently, more than 70 percent of the department’s $224 billion annual budget goes to the federal student aid program, which has also become a frequent Republican target. Mr. Trump is seeking to restrict public-sector loan forgiveness, and has said fewer students should attend four-year colleges.

The agency provides more than $90 billion in new loans to students annually, which are distributed by colleges and serviced by the federal government through private contractors. It also offers $39 billion in Pell Grants annually to low-income students, which generally do not need to be paid back. It administers the federal work-study program and gives grants to students who promise to work as teachers in hard-to-staff subjects or schools.

It has had opponents since the beginning.

Opposition to the Department of Education is today associated with Republicans. But the agency began its life with fierce opponents on both sides of the aisle.

President Jimmy Carter established the department, often known simply as Ed, in 1979, fulfilling a campaign promise to the nation’s largest teachers’ union, the National Education Association. He did so over the objections of his own presidential transition team and many in Congress — including fellow Democrats.

Some staunch liberals believed all of the issues affecting children — health care, cash welfare and education — should be handled by a single federal agency, then known as the Department of Health, Education and Welfare.

Still, over the next four decades, Ed became a part of the beltway firmament, popular with Democrats and many Republicans, too. Many of the programs Ed oversees are sources of bipartisan comity, such as funding for vocational education.

Gareth Davies, a historian who has written about the founding of the Department of Education, said the revival of conservative opposition to the agency shows “just how far the G.O.P. has moved in the past two decades, from compassionate conservatism to culture wars.”

Mike Petrilli, president of the Thomas B. Fordham Institute think tank, and a former Department of Education staffer under President George W. Bush, called the gesture toward shuttering the agency a distraction from problems like the record-low reading scores of American students, released in January.

He suggested that Mr. Trump should host a governor’s summit in Washington to focus on the problem, particularly on the question of whether screen time is harming children’s academic abilities.

“If you wanted to solve this problem and show leadership,” he said, “you would talk about the real crisis.”

It was an obscure, 44-word demand toward the end of the Trump administration’s ultimatum to Columbia University this month ordering a dramatic overhaul of admissions and disciplinary rules. But it could prove to have consequences for colleges and universities nationwide.

With $400 million in canceled government grants and contracts on the line, federal officials ordered Columbia’s administration to place the university’s Middle Eastern studies department under academic receivership for at least five years.

Typically, a receivership is handled internally. University administrators can take the rare step of imposing the measure when a department descends into chaos. It is viewed as a last-resort solution to extended periods of internal strife and dysfunction.

This time is different. The call for a receivership is coming from outside the university — and directly from the White House. And it arrives at a moment when dozens of other colleges and universities are facing federal inquiries and fear a fate similar to Columbia’s.

“It is one small department in one university,” said Sheldon Pollock, a retired former chair of the Middle Eastern studies department at Columbia. “But it will reverberate across the entire country.”

The interdisciplinary program at the center of the government’s demand — the Middle Eastern, South Asian and African Studies Department — has been in a pitched battle for decades over its scholarship and employment of faculty members who describe themselves as anti-Zionist.

Several historians and veteran professors said that the move by the federal government to intervene in an academic department at a private university would be unparalleled in the modern history of U.S. higher education.

Laurie A. Brand, a professor emerita at the University of Southern California, who described the department as one of the most respected in the field, compared the move to the Turkish government’s centralized control of higher education during its “hard authoritarian turn” in the 2010s.

“I certainly don’t remember a case in the United States,” said Dr. Brand, the chair of the Committee on Academic Freedom at the Middle East Studies Association, an organization of scholars who focus on the region.

The swirling questions about the department’s future have emerged as the latest crisis for Columbia, where pro-Palestinian demonstrations against the war in Gaza ignited a national protest movement and animated debate over free speech and antisemitism. The federal government accused the university last week of failing to safeguard students and faculty members “from antisemitic violence and harassment,” calling for changes that include the school formalizing its definition of antisemitism.

The government said that it had extended its deadline to the end of Friday for Columbia to respond to its ultimatum, which would include offering a timeline for placing the Middle Eastern studies department under receivership.

College administrators across the nation are closely watching whether Columbia acts with deference or defiance.

As higher education institutions face federal scrutiny, many see the dispute over the department as a high-stakes test case for other Middle Eastern studies programs — and for other endeavors that could run afoul of conservative orthodoxy, such as centers for the study of climate change or gender and sexuality.

Dr. Pollock described the government’s “intrusion” as “jaw-dropping” and “a historic and astonishing event.”

Such a move would signal “the beginning of the end of the American university as we’ve known it since 1915,” the year that the American Association of University Professors first codified guidelines and practices for academic freedom.

A spokeswoman for the Department of Education, one of three federal agencies named in the letter to Columbia, did not respond to questions about the rationale for the receivership.

In a letter to the university on Wednesday, Columbia’s interim president, Katrina A. Armstrong, seemed to acknowledge the growing concern over how the school might respond.

“Legitimate questions about our practices and progress can be asked, and we will answer them,” Dr. Armstrong wrote. “But we will never compromise our values of pedagogical independence, our commitment to academic freedom or our obligation to follow the law.”

President Trump has previously homed in on Middle Eastern studies programs for potential bias, including in his first term. The Education Department, under its former head, Betsy DeVos, ordered Duke University and the University of North Carolina at Chapel Hill to remake their jointly run Middle East studies program, accusing it of offering students a biased curriculum in violation of federal funding standards.

It was one example of the charged conflict over Middle Eastern studies, which has historically inspired debate, in part because the discipline can highlight academic scholarship that casts Israel in a negative light. At some institutions, students, professors, alumni and donors have been divided over the distinction between anti-Zionism and antisemitism in such work — and whether the two should be regarded as distinct issues.

Columbia’s Manhattan campus — and its roughly 50-member Middle Eastern, South Asian and African Studies Department — have been a hot spot for these disputes.

The department was a central focus of a 2004 documentary called “Columbia Unbecoming,” which interviewed students who had taken classes in the department and described facing intimidation from faculty members for their pro-Israel views. Its central thesis, which has been strenuously debated, depicted a systemic silencing of Jewish students in campus culture.

During the past 17 months of fighting in Gaza, the department has come under a wave of renewed scrutiny, including during a high-profile hearing on antisemitism last spring.

A number of Congressional Republicans took issue with some faculty members, including Joseph Massad, a tenured professor of Palestinian Christian descent who teaches modern Arab politics and intellectual history. Many students and alumni were enraged over an article he wrote after the Hamas attack, which included descriptors like “resistance offensive” and “awesome.”

Michelle Steel, a former Republican representative from California, said during the hearing that the article illustrated that the department had been “extremely hostile to both Israel and Jewish students” for more than two decades, and asked whether the school would consider “placing the department into receivership.”

Nemat Shafik, Columbia’s president at the time, avoided a direct answer. “Academic departments at Columbia are — there isn’t really a notion of receivership,” Dr. Shafik, who resigned from her post in August, responded.

Some Jewish organizations in recent months called on Columbia’s leadership to overhaul the department. Kenneth L. Marcus, the founder of the Brandeis Center in Washington, D.C., said that many Jewish students during the past two decades had “simply been warned to avoid the program altogether.”

It may be debatable whether academic receivership is the answer, Mr. Marcus said. Still, he called it a milestone for federal officials to recognize “that the campus problem cannot be solved without a faculty solution.”

The chair of the Columbia department, Gil Hochberg, did not respond to requests for comment.

It remains unclear what an academic receivership might entail. Several advocates of academic freedom raised concerns in interviews that the government might seek to influence the selection of a new department chair, who could have broad leeway to reshape course content or pursue the dismissal of tenured faculty members.

Others worried that the move could set a precedent for the Trump administration to make threats to federal funding at other universities over scholarship that it finds unfavorable. One professor wondered whether history departments could come under fire for courses that federal officials believed portray slavery and segregation too negatively.

Radhika Sainath, a senior staff attorney at Palestine Legal, which is representing Palestinian students in a civil rights case against Columbia, said that Middle Eastern studies departments had often been targeted for punishment or defunding because they challenged dominant narratives about Israel.

Ms. Sainath called the receivership demand “straight out of an authoritarian playbook where attacking universities is the first step,” and “any institution that represents opposition to Trump’s agenda” could be next.

It would not be Columbia’s first experiment with academic receivership. Some two decades ago, school administrators placed the Middle Eastern studies department under a one-year receivership and appointed an interim chair in part because of struggles to find a new leader, Dr. Pollock, the former chair, said.

And amid internal disputes over cultural shifts in the study of literature, Columbia leaders appointed a scholar from a Pennsylvania university to lead the English department in the early 2000s. A weekly newspaper in New York described the stakes in now familiar terms: “Crisis at Columbia.”

David Damrosch, a Harvard professor of comparative literature who was a member of Columbia’s English department at the time, said the move helped mend divisions. But he added that a receivership “might be the single most dangerous thing the administration has demanded out of everything.”

To Dr. Damrosch, who has studied academic culture at colleges, the current turmoil was vaguely reminiscent of a 1940s episode at the school now known as Iowa State University.

The school’s economics department — in a paper on economic policy for wartime food production — had proposed replacing butter with margarine, said Dr. Damrosch. The dairy industry and its supporters in the state legislature “went ballistic,” he said, pressuring the school’s president to place the department under receivership.

The move triggered an immediate backlash and mass departure of faculty members.

It might have also played a small role in the reshaping of the higher education landscape: At least six professors fled to Chicago, where they helped build one of the most renowned economics departments in the world.