American Enterprise Institute scholar Charles Murray wrote a fierce rebuttal this weekend to the left-wing demonstrators who attacked him and a Middlebury College professor last Thursday during an appearance on the Vermont-based campus.

Murray was scheduled to speak at Middlebury on the subject of his 2012 book, “Coming Apart,” and how its analysis of the white-working class explains the 2016 election. Demonstrators, however, forced him to deliver his address via livestream video and attacked him and Professor Allison Stanger as they were leaving campus.

Stanger suffered neck injuries and is now having to wear a neck brace following the assault. (RELATED: Leftist Students Physically Assault Conservative Scholar, Professor Over Speech)

Demonstrators justified their violence over the allegation Murray is a “white supremacist” because his 1994 book, “The Bell Curve,” connected genetics with socioeconomic outcomes.

Murray recalled the disruptions and assault in his letter published on AEI’s website Sunday.

“[M]any looked like they had come straight out of casting for a film of brownshirt rallies,” the conservative scholar recalled of some of the demonstrators who wished to attack him. “In some cases, I can only describe their eyes as crazed and their expressions as snarls. Melodramatic, I know. But that’s what they looked like.”

He also recalled that many of the members of the mob that attacked him and Stanger were wearing ski masks. “That was disquieting.”

He narrates the harrowing escape from the angry mob that surrounded his car and jumped on its hood, and how the protesters forced the scholar and his dinner party to choose a restaurant several miles away from campus to avoid any further attacks.

“Absent an adequate disciplinary response, I fear that the Middlebury episode could become an inflection point,” Murray wrote of his thoughts on the larger meaning of the protests.

“If this becomes the new normal, the number of colleges willing to let themselves in for an experience like Middlebury’s will plunge to near zero. Academia is already largely sequestered in an ideological bubble, but at least it’s translucent. That bubble will become opaque,” he added. “Worse yet, the intellectual thugs will take over many campuses.”

According to Murray, things have gotten much worse on college campuses since the release of his most controversial book, “The Bell Curve.”

“In the mid-1990s, I could count on students who had wanted to listen to start yelling at the protesters after a certain point, ‘Sit down and shut up, we want to hear what he has to say,'” he said. “That kind of pushback had an effect. It reminded the protesters that they were a minority. I am assured by people at Middlebury that their protesters are a minority as well. But they are a minority that has intimidated the majority. The people in the audience who wanted to hear me speak were completely cowed.”

In Murray’s opinion, that’s a win for the “intellectual thugs.”

“That cannot be allowed to stand,” he argues. “A campus where a majority of students are fearful to speak openly because they know a minority will jump on them is no longer an intellectually free campus in any meaningful sense.”

He puts believes college professors have the power to effectively push back against this illiberal behavior and set an example for free speech defense. But Murray questions whether there are enough faculty in America to openly express such sentiments and thinks “a minority of faculty are cowing a majority in the same way that a minority of students are cowing the majority.”

While the AEI scholar hopes severe penalties will be imposed on the offending students, he believes Middlebury’s reaction “will fall short” due to the potential for intense backlash toward tough consequences from parents and other universities.

Overall, he’s pessimistic about higher education’s treatment of free speech and views last week’s event as part of a larger trend.

“What happened last Thursday has the potential to be a disaster for American liberal education,” Murray concluded his letter.

Follow Scott on Twitter and purchase his new book, “No Campus for White Men,” on Amazon