It often said that "free speech does not mean freedom from consequences of speech". The idea is that only a government restriction on your ability to speak counts as a violation of free speech. I want to challenge this piece of conventional wisdom, which I have in fact deployed in my own writing in the past. Here's how I put it when discussing some aftershocks of the Cartoon Crisis in Denmark:
freedom of speech is threatened when the state prevents people from speaking freely. When your neighbour punches you in the mouth for saying something he finds offensive your freedom of speech has not been threatened.
I still stand by that. But there's a corollary that I think we too often forget. If my neighbor punches me in the mouth because I offend him, he is still guilty of assault. If the state considers my "offensive" remark to be a mitigating circumstance and therefore does not prosecute the assault charge as it would otherwise do, then my free speech rights have in fact been violated by the state, since it is essentially declaring me fair game for violent reprisals. Similarly, I would argue, if the state does not help me secure the site of a peaceful assembly, minimally by threatening to enforce trespassing laws against disruptive protesters, then my right to free speech has been violated.
Alice MacLachlan says she teaches John Stuart Mill's conception of free speech. As I pointed out in another context, Mill made the important point that free speech isn't just the right of a person to speak; it's also the right of an audience to hear. Accordingly, if a state, or a university, values free speech, it must enforce rules of decorum. It must protect what Mill called, not just "free speech", but "the liberty of thought and discussion".
That is, the state must not take a characterization of a speaker's ideas (whether as "false" or as "drivel" or as "hurtful") as a good reason to prevent that speaker from speaking. It is especially the right to express false notions that Mill would have wanted us to protect. How else could they be corrected?
One last point. While it is true that constitutionally protected speech is only respected or violated by the state, there's nothing to prevent a university from declaring itself a "free speech zone", meaning that it refrains from punishing its students and faculty for speaking their minds and enforces the rules of decorum that make rational debate possible. Even a bold corporation could guarantee its employees free speech rights, meaning simply that it would levy no consequences against people merely on the basis of what they say in public, even about the company. In that sense, "free speech" is actually freedom from (and protection against) at least some of the consequences of speaking. It is also, implicitly, a promise of the maintenance of order.
Update: one could probably always footnote a post on this issue with a post by Ken White at Popehat.