I covered this in my book The Philosopher in the City (Princeton, 1981). The heckler’s veto is the device that the ACLU is pleased to offer precisely because they don’t want to judge the content of the speech. They have preferred to wait for the violence to break out, and in that way they do create the heckler’s veto. They enfranchise the violent to end the freedom of the speaker. One paradigm might be Lou Costello looking for Bagel Street: He stops people to ask for directions, and each time he triggers an idiosyncratic response–and gets beaten up. (“My husband died on Bagel Street!”) Costello had no way of knowing that his innocent asking of directions would set off these effects. If some people are holding a peaceful demonstration, their right to engage in a peaceful demonstration cannot be revoked merely because the lawless and intolerant are willing to act our their character with violence.
Justice Jackson, in the famous Terminiello case, thought it was quite different when Terminiello, in the presence of a hostile crowd, just egged them on with attacks on Jews and others. Just as we know the difference between a burning box and a burning cross, we know the words and symbols that are established in the language as terms of assault. The moral reflexes of commending and condemning, praising and attacking are built into our nature. The words or symbols will be found then to carry those functions. The meaning of words will shift over time, but at any given time people will have a sense of the words that are clearly established in the language as terms of assault and denigration. As I pointed out in my piece, we could easily give juries the instruction that they should convict only when the words, arrayed in the context, were clearly terms of insult or assault. And so we can tell the difference between Nazis dancing on the stage in The Producers and “Springtime for Hitler,” and a band of self-styled Nazis marching in a community containing survivors of the Holocaust, in Skokie, Ill.,
There is a world of difference between saying that we can restrain or punish people who burn crosses outside the homes of black families, and saying that we can restrain, with comparable justification, the man who recites Shakespeare’s Sonnets in the park and just happens to set off a violent reaction. In the first case, the meaning of burning cross, in that setting, is clearly fixed in our experience and understanding. But in contrast, the person reading the Sonnets has no way of anticipating that he is doing something that will have the sting of an assault. The willingness of the violent to act simply cannot supply, in itself, a justification for restraining that speech. The question must always involve a test of the words and symbols themselves in the context in which they are used. To say that we are incapable of making those discriminations is to back into Justice Harlan’s relativism: “One man’s vulgarity is another’s lyric.”
The fuller argument here is contained, as I say, in The Philosopher in the City. I don’t know what Justice Breyer said, but I’d post a caution to Nina–whose judgment is usually impeccable: There is a serious argument to be made here, and it is just not true that if we take seriously the understanding that there are indeed, in this world, words of “assault” and “insult,” that we committed then to honoring a “heckler’s veto.”