If you want to see a nearly perfect example of everything that's wrong with campus call-out culture these days, watch this video of Josh Blackman's attempt to deliver remarks at CUNY School of Law.

Blackman, an associate professor at the South Texas College of Law in Houston, supported Donald Trump's decision to rescind Deferred Action for Childhood Arrivals (DACA), agreeing that Barack Obama exceeded his legal authority when he set up the program, which allows some immigrants who came to the country illegally as children to avoid deportation. But Blackman supports the DREAM Act, which would grant residency status to many of these same people.

That distinction mattered little to the student activists who crashed Blackman's event last month, calling him a racist and white supremacist. Blackman was merely "gaslighting" them, they said. They accused CUNY of giving a platform to an oppressor. They tweeted, "My existence > your opinion." They heckled Blackman, making it impossible for him to deliver his prepared remarks. A productive conversation was possible only after the activists left the room, furious that the administration had threatened to discipline them.

That's according to video footage and Blackman's write-up of the event for National Review. The entire post is worth reading. Instead of attempting to recap it, I will note a few aspects of the episode that will be familiar to readers who follow the debate about political correctness on campus:

1. "Hate speech isn't free speech" was one of the activists' mantras. Ironically, Blackman had intended to discuss free speech and the law. It's a shame students who are confused on this topic—who wrongly believe that the First Amendment does not protect hate speech, or that it shouldn't—were unwilling to be educated by a legal scholar. But this is an attitude I encounter on college campuses all the time.

2. Activists thought CUNY should have prevented the event from taking place for reasons of safety. Never mind that the only person whose safety was threatened by Blackman's presence was Blackman himself, who prior to the event formulated an exit strategy at the urging of a public safety administrator. The student activists believed the airing of an opinion with which they disagreed was tantamount to physical violence against marginalized communities.

3. A student of color in the audience who disagreed with Blackman nevertheless wanted the event to proceed and was looking forward to asking tough questions. For saying that, the student was branded a traitor to the revolution. "Why are you here?" one activist asked him. "Why aren't you with us?" The same thing happened at the University of Michigan when Charles Murray attempted to speak there last October: Murray's presence was deemed an attack on marginalized persons, although some of the people in his audience were marginalized persons who didn't feel attacked by the speech and in fact wanted to hear it.

4. Students showed remarkable contempt for the thing they are ostensibly studying: the law. This exchange was noteworthy:

There were audible gasps in the room. "This might surprise you. I think the DREAM Act is a good piece of legislation." Someone yelled out "Gaslighting." I continued, "Were I a member of Congress…" Someone interrupted me. I said, "Let me speak, please." A number of students shouted out, "Nah." I continued, "Were I a member of Congress, I would vote for the DREAM Act. My position is that the policy itself was not consistent with the rule of law. Which teaches a lesson." Someone started snapping and booing. "The lesson is you can support something as a matter of policy." Someone shouted, "What about human rights?" I continued, "but find that the law does not permit it. And then the answer is to change the law." A student shouted out "F**k the law." This comment stunned me. I replied, "F**k the law? That's a very odd thing. You are all in law school. And it is a bizarre thing to say f**k the law when you are in law school." They all started to yell and shout over me.

There is an important distinction between thinking a particular law should be changed and thinking law itself is invalid. The latter seems to be the position of the student radicals studying law at CUNY. I am reminded of the activists at Pomona College who published a statement asserting that "objectivity" was a white supremacist construct and the "search for truth" was an attempt to silence minorities.

That Blackman was eventually able to speak to the students in the audience who were interested in an exchange of ideas is evidence that administrators can prevent radical students from shutting down students—and that they can do so peacefully, without arresting or punishing the hecklers. The tide began to turn against the activists only after a CUNY administrator stood up and said the following:

All right, listen. Everybody stop. Let me tell you something. The university rules are people get to speak. You may protest. You may protest. But you may not keep anyone from speaking. If you do, I have other things to do, I will be back. Or you can resolve this yourselves. Or you can have me resolve it.

"We're not children!" one of the activists fired back. "You can't talk to us like that!" But the balance of power had shifted, and a few minutes later, the hecklers gave up and left.

It turns out that reminding students of their obligations as members of a community that values free speech, and imploring them to cease their heckling, can work. Something similar happened at the Murray event after an administrator spoke up.

The activist students understand the dynamics at play. When they feel they have the power, and no one will try to stop them, they proceed to shut down events that offend them. When they perceive that power has shifted to the rest of the audience, to the administrators, or to the speaker, they leave. Confronting irate student protesters isn't easy, but it seems the best thing for professors and administrators to do in these situations.