The primary benefit of the University of North Carolina system’s new free-speech policy will be to protect the freedom of professors, students, and other North Carolinians to listen to whatever speakers they wish to hear without having their rights trampled by violent or abusive protestors.

That’s more than enough to justify UNC’s adoption of the policy, which was required by a free-speech law the General Assembly enacted earlier this year. But it turns out that there has been a side benefit: outing the illiberal views of two organizations, the American Civil Liberties Union and the American Association of University Professors, that tried to convince the UNC Board of Governors not to adopt its free-speech protections.

I’ve long believed that the American Right should try to reclaim the term “liberal” from the American Left, which misappropriated it nearly a century ago to describe what is really progressivism — a philosophy that elevates political power over constitutional constraints, government institutions over private ones, and the rule of experts over the freedom of individuals to make their own decisions.

Now that left-wingers seem to prefer the term “progressive,” anyway, there may be a chance, however fleeting, to recover the original, classical meaning of liberalism.

John Locke, the 17th-century philosopher often viewed as the founder of political liberalism, would today be called a libertarian or a limited-government conservative. Locke argued that governments were necessary to secure the rights of individuals. His successors, from Adam Smith in the 18th century to Friedrich Hayek in the 20th century, extended liberalism’s logic a bit further to encompass certain public goods that might require a governmental role, as financier if not necessarily as provider.

One of the core concepts of true liberalism is that people should be as free as possible to live according to their own principles, which includes the right to form or join voluntary associations.

If you want to create a pressure group to convince others to become vegans, because it will spare animals or save the planet or whatever, liberalism requires that I respect your freedom to do so. Liberalism also requires, however, that you respect my rights to stay out of your group and to speak against it if I like.

On a public university campus, in particular, a basic liberal understanding of the rights of free expression and free association would lead inevitably to the kind of policy that the UNC system just adopted. If a student group or professor invites a speaker to campus, you and I have the right to attend or not attend as we see fit. If I attend and you show up at the auditorium with your comrades to shout down the speaker, so that I and other audience members can’t hear her, you aren’t exercising free expression or free association. You are suppressing the freedom of others. There is no “heckler’s veto.”

The ACLU and AAUP apparently think otherwise. In its statement against the UNC policy, the ACLU speculated that “peaceful protesters chanting outside an event being held in a campus building could be shut down and face harsh consequences, not for blocking an entrance or shouting violent threats, but for simply chanting loudly outside.” The AAUP blithely asserted that the policy showed “a preference for speech over counter-speech, which is contrary to First Amendment law.”

This is pretty simple, really. If protestors are shouting so loudly outside the door that the audience can’t hear the speaker, the protestors aren’t engaging in “counter speech.” They are trying to suppress other people’s rights. The precise location of the protest can’t possibly be a sufficient defense. Would the ACLU or AAUP think it acceptable for outside protestors to employ bullhorns, sirens, or loudspeakers? If not, why not? If so, describing such behavior as “counter speech” protected by the First Amendment would be idiotic and appalling.

We all know from recent experience what the game is here. Left-wing groups want to shut down campus speakers they don’t like. Real liberals will always say no to that.

John Hood is chairman of the John Locke Foundation and appears on the talk show “NC SPIN.” You can follow him @JohnHoodNC.