Just a few years ago, university statements on the day’s social and political issues abounded.

When Russia attacked Ukraine in 2022, Harvard’s president at the time called it “senseless” and “deplorable,” and flew the invaded country’s flag in Harvard Yard. After George Floyd died under the knee of a white police officer, Cornell’s president said she was “sickened.” The University of Michigan’s president described the Oct. 7, 2023, violence against Israel as a “horrific attack by Hamas terrorists.”

But over the last year, each of those universities has adopted policies that limit official statements on current issues.

According to a new report released on Tuesday from the Heterodox Academy, a group that has been critical of progressive orthodoxy on college campuses, 148 colleges had adopted “institutional neutrality” policies by the end of 2024, a trend that underscores the scorching political scrutiny they are under. All but eight of those policies were adopted after the Hamas attack.

“We must open the way for our individual faculty’s expertise, intelligence, scholarship and wisdom to inform our state and society in their own voice, free from institutional interference,” said Mark Bernstein, a regent at Michigan, after adopting the policy in October.

He said the university had historically refrained from issuing statements on momentous events, like the assassinations of Abraham Lincoln and John F. Kennedy or during the two world wars.

“So institutional statements are a modern phenomenon and a misguided venture that betrays our public mission,” he said.

The universities are adopting such policies at a time when the Trump administration has moved aggressively to punish them for not doing enough to crack down on antisemitism and for embracing diversity, equity and inclusion policies.

On Friday, the administration announced that it was pulling $400 million from Columbia, a move that sent shock waves across higher education. The administration has already said it is looking to target other universities.

Universities ramped up issuing statements on hot-button issues about a decade ago, after the rise of the Black Lives Matter movement and the police shootings of Black people in places like Ferguson, Mo., said Alex Arnold, director of research at the Heterodox Academy.

Some conservatives had long lamented such statements and believed they veered too leftward. Speech groups like the Foundation for Individual Rights and Expression worried that they discouraged dissent. For a while, the statements were hardly the subject of widespread controversy.

The Hamas attack and the war that followed changed the equation.

The Israeli-Palestinian conflict has always split the left, but the attack on Oct. 7 and the war that followed sharpened those divisions. The statements that universities issued on the attack and Israel’s bombing of Gaza came under scrutiny, and were often criticized for being too late, too weak, too biased — or all three.

University leaders, under pressure from donors, lawmakers and the public, began to ask: Why put out statements at all?

About four out of five colleges that adopted neutrality policies are public and face scrutiny from state lawmakers. Several states, including Texas and Utah and North Carolina, forced their public universities to adopt such policies. Others, like Tennessee, are considering it.

Most of the new policies apply to senior administrators, like college presidents and provosts. Others also encompass units like academic departments. And many apply to faculty members when they are speaking in an official capacity, but often make clear that faculty are free to express personal views, according to the Heterodox Academy.

“The whole experience of coping with the campus controversy triggered by the Hamas attack has really gotten institutional leaders to think carefully and to reflect on what the function of our institutions of higher education is,” Mr. Arnold said. “I do think this is probably going to be a pretty durable change.”

Critics of the neutrality trend have argued that administrators are merely sidestepping difficult debates on the Middle East conflict, and scared of angering donors and lawmakers.

After Clark University, in Massachusetts, said it would shy away from taking positions, the school newspaper’s opinion editor called the move a “fake policy” designed to curb discussion of the conflict.

But even universities that adopted such a policy have not gone totally silent on contested political issues.

At an Anti-Defamation League event in New York City last week, Michigan’s president, Santa Ono, called the effort to boycott, divest and sanction Israel antisemitic, and said his response had been to invest even more in those partnerships.

In an email, the university said the new neutrality policy adopted a “heavy presumption” against issuing statements “not directly connected to internal university functions.”

“Combating antisemitism and making sure we have an environment where all students can thrive and succeed is part of our moral and legal obligation, and absolutely connected to our internal functions as an institution of higher education,” said Colleen Mastony, a Michigan spokeswoman.

Presidents are often stumbling over their new policies. During an October interview with the school newspaper, Harvard’s president, Alan Garber, called a statement by pro-Palestinian students “offensive,” prompting the editorial board to tell him to “follow your own policy.”

Last month, the American Association of University Professors, a faculty rights group, issued a statement on neutrality that was, more or less, neutral. It stated that the idea “is neither a necessary condition for academic freedom nor categorically incompatible with it.”

The re-election of Donald Trump is now testing those policies.

As the new administration, which has described universities as “the enemy,” ratchets up its attack on higher education, colleges are under greater pressure to be voices of resistance.

But many college presidents have been spooked into silence, said Patricia McGuire, president of Trinity Washington University, a small Catholic institution three miles from the White House.

“They look at what happened to Claudine Gay, and some of the other presidents,” she said, referring to the former Harvard president who resigned last year after a congressional hearing on antisemitism. “And they’re like: ‘I don’t want that to happen to me. So I’ll just shut up and hunker down, and hope this cloud passes.’”

No university is more associated with neutrality than the University of Chicago, where incoming students are furnished with the Kalven Report, the 1967 document that made the case for neutrality. The report, penned as violence upended college campuses during the Vietnam War, said the university “is the home and sponsor of critics; it is not itself the critic.”

Tom Ginsburg, director of the Forum for Free Inquiry and Expression at Chicago, says adopting neutrality signals to lawmakers that colleges are committed to welcoming diverse viewpoints.

“Because the statements tended to reflect the majority views on campuses, which are overwhelmingly left-leaning,” he said, “you can see how adopting it would be a way of saying to lawmakers: ‘This isn’t who we really are. We’re not indoctrinating people with contested positions.’”

But even the Kalven Report included a caveat that doesn’t settle precisely when universities should issue statements. Neutrality, the report says, still allows colleges to speak out when “the very mission of the university and its values of free inquiry” are threatened.

That moment is now, said Ms. McGuire of Trinity Washington University. “The erosion of knowledge and expertise that this administration has embraced is very, very scary,” she said, “and higher ed should be calling it out at every turn.”