I was talking awhile ago to University of Wisconsin law professor Patricia Williams, author of the recently published "The Alchemy of Race and Rights." The subject was whether to punish offensive speech on campus, and I was grandly waving the First Amendment.

"There are people," she said, looking straight at me, "who act as if once they say, 'First Amendment,' the conversation should stop."

That stopped me. As it was meant to. The First Amendment should not be used as a bludgeon. Nor should those exercising it in ways that infuriate others in the community consider themselves immune to the offensive reactions of their targets.

A bookstore owner who sells the Protocols of the Elders of Zion -- as at least one does in Los Angeles -- may be angered by a picket line of indomitable Jews, some of them perhaps carrying a copy of Alan Dershowitz's "Chutzpah," which urges Jews to unfurl their identity. The bookseller might claim that his freedom of expression gives him the right not to lose business because of his views. Yet the picket line is protected speech.

But if members of the picket line successfully pressure the bookseller's landlord to throw him out on the street, then the bookseller has a point; and probably a Jewish civil liberties attorney representing the bookseller will try to make a case out of it even though there is no state action.

The contrapuntal nature of the First Amendment was the subject of two letters to The Post (July 24) claiming that I -- as one of them put it -- have "a cramped view of free expression."

At issue was the insistence of Brigit Kerrigan, a Harvard senior last semester, on flying a Confederate flag from her window. This did not endear her to many of the students and faculty. Almost as annoying, I suspect, was some of her public statements such as, "If they talk about diversity, they're gonna get it."

As diversity is defined these days on collegecampuses, it has its bristlingly correct limits -- a point that Kerrigan, a conservative, was making in about as provocative a way as she could.

The administration did not order her to take down the flag because of Harvard's commitment to free speech, even if that speech offends "the feelings of many members of the community." But the then-president, Derek Bok, did exercise his right to criticize the flying of the stars and bars as "insensitive and unwise."

Kerrigan took a lot of heat, and, says one of the letter writers, those responses -- which I described as protest marches, forums, editorials and most wounding of all, a letter circulated by faculty at the house where she lived -- were actually "an example of the ideal of free expression at work."

How, then, could I have criticized those responses as "an assault on freedom of expression?" I didn't. Moreover, a letter writer added, if Kerrigan caused discomfort or pain by showing that dreadful flag, those opposing views that caused her pain or discomfort were also part of the counterpoint of free expression.

That is indeed the nature of the free-expression fugue. My interest, however, was in the inability of so many students and faculty at this center of enlightenment to understand that Kerrigan did have a right to fly that flag. While the administration grumblingly let the flag stay up, much of the reaction by the rest of the Harvard community was venomous and was clearly intended to put so much pressure on Kerrigan that she would haul down the flag and then deliver a penitential oration in front of Kirkland House, where she lived.

The letters circulated by faculty members in Kirkland House explicitly ostracized her from that community. That, along with all the rest, is entirely within the bounds of free expression. It also reveals a hard smallness of spirit.

The other letter writer to The Post claimed that I "isolated" Brigit Kerrigan "from the responsible exercise of symbolic speech" rather than focusing on her "stubborn insensitivity." Thereby, I "demeaned free expression and ultimately put this right in greater jeopardy."

I recommend that he read both decisions by Justice William Brennan in the 1989 and 1990 flag-burning cases. And then he might donate those decisions to the library at Kirkland House.

But shouldn't Brigit Kerrigan have been much more sensitive to the views of decent people at Harvard and kept her flag in her trunk? But if she did so, that wouldn't have been Brigit Kerrigan. So she took her lumps and survived. And those on the other side expressed themselves freely too, but not as memorably. Nor with as much credit, ultimately, to Harvard.