Last week, author and conservative scholar Charles Murray was surrounded by an angry mob after trying to give a lecture about his most recent book at Middlebury College.

Hundreds of protesters, including masked demonstrators who climbed on the hood of the car and pounded on windows as he tried to leave, objected vehemently to a book he co-wrote in the 1990s, “The Bell Curve,” calling it racist. 

Robert Shibley, executive director of the Foundation for Individual Rights in Education and a graduate of Duke University and its law school, writes his opinion that something fundamental is at stake when a controversial speaker is forced to flee campus. — Susan Svrluga

Free speech on campus is facing a profound threat.

Not at the hands of President Trump, nor even at the hands of the administrators and lawyers who have done so much to erode academia’s respect for freedom of expression.

No, as highlighted by the violent disruption and end of Charles Murray’s visit to Middlebury College in Vermont last week, the immediate crisis comes from one of freedom’s most ancient enemies: the angry mob.

It’s time for college leaders and law enforcement to take a stand: In our nation, this is not what democracy looks like.

While Americans rightly tend to focus on threats to freedom of speech from the authorities, we cannot overlook the danger of allowing people to be silenced by groups prepared to be violent.

History is littered with such warnings, from Diogenes to Robert F. Kennedy, who, on the day after the Rev.  Martin Luther King’s assassination, said, “A sniper is only a coward, not a hero; and an uncontrolled, uncontrollable mob is only the voice of madness, not the voice of the people.”

That voice of madness led to  Murray being forced to give his talk on social stratification in America by videolink after disruptive protesters made Murray’s actual presence before the audience impossible.

It caused masked protesters to hurl a stop sign at the car in which  Murray was attempting to leave, and sent his discussion partner, Prof. Allison Stanger, to the hospital with a neck injury after a protester grabbed her hair.

And it led Murray and Stanger to flee a post-event dinner after being warned that demonstrators were coming, after which, in Stanger’s words, she and Murray decided “it was probably best to leave town.”

That voice of madness also famously left the University of California, Berkeley, aflame in February, with masked vigilantes setting fires, smashing windows  and attacking would-be speechgoers. And, as further violent attacks on marchers in the city of Berkeley this weekend demonstrate, the disease is not only confined to campus, though it’s perhaps at its most obvious in the very places that are supposed to be dedicated to the exchange of ideas.

While peaceful protesters must be accommodated and protected, there can be no excuse for violence in response to mere speech, and the authorities must ensure that attempts to shut down speakers do not succeed.

UC-Berkeley’s February approach, with only three reported arrests and with dozens of police barricaded inside a building while attacks on people and property took place just yards away, has to be counted as a failure.

Those persuaded to write off the Berkeley mob’s violent response to provocateur Milo Yiannopoulos as understandable should realize that the well-publicized lack of consequences undoubtedly encouraged the use of similar tactics to silence a sober academic in small-town Vermont.

Middlebury College may be charting a different course.

President Laurie Patton directly apologized to  Murray and  Stanger on behalf of Middlebury in an official statement, visited Stanger in the hospital, and promised that the college “will be responding in the very near future to the clear violations of Middlebury College policy.”

Some Middlebury students even reached out on their own to the Foundation for Individual Rights in Education (FIRE), where I work, to tell us that they believe that  Patton will do the right thing.

Yet the same students also begged FIRE for anonymity, saying, “we are currently terrified to express any opinions that do not fall in line with the culture of moral authoritarianism that is permeating this campus.”

FIRE has heard versions of this statement from students on hundreds of other campuses.

Were students this widely uncomfortable about any other matter, college leaders would rush to address it.

Instead, campuses continue to shore up this authoritarianism through efforts such as the more than 230 “bias response teams” nationwide that summon students and professors for lectures (or worse) on how their use of language might violate campus rules or hurt the feelings of some protected class of people.

This only encourages the vigilante censors to believe that silencing opponents is what good and moral people do. It’s not.

Even if academia does nothing to address the immediate problem, law enforcement has a role to play. Local police can and should aggressively investigate reports of violence against speakers or their audiences. Smartphone pictures and video footage should give detectives plenty to go on, enhanced by their ability to legally request text messages and social media updates that may shed light on the identities of perpetrators.

While police forces may understandably prefer to spend their time pursuing major crimes, it would be a mistake to allow our democracy to be undermined simply because dissenters are being beaten and not murdered.

Let’s face it: Right now, when it comes to violent censorship, crime pays.

Until that changes, we must expect more of the same — and as ground zero for mob attacks on free speech, it’s time for colleges to lead the way.