Whether a sophist like Milo Yiannopoulos may speak at a public university like Berkeley is less a question of what the law is than of what the law should be. The Supreme Court has been consistent, during the past half century or so, in its broad interpretation of the First Amendment. “Speech can’t be prevented simply because it’s offensive, even if it’s very deeply offensive,” Erwin Chemerinsky, the dean of the U.C. Berkeley School of Law and the co-author of a book called “Free Speech on Campus,” told me one morning in his office. He grimaced sympathetically as he talked, like a doctor delivering bad news. “I would argue that it’s generally a good idea to protect speech we don’t like, even when we’re not legally obligated to do so, but in this case we are.”

Voltaire, anti-Semite and sage of the Enlightenment, is credited with the aphorism “I disapprove of what you say, but I will defend to the death your right to say it.” Chemerinsky, arguably the foremost First Amendment scholar in the country, believes, in the Voltairean tradition, that free speech is the bedrock of a free society. I asked him about the Antifa activists who had vowed to shut down Yiannopoulos’s events by any means necessary. “Violence is never protected by the Constitution,” he said. “And preventing the speech of others, even by using one’s own speech, is called the heckler’s veto, and it is not protected, either.”

On talk radio and social media, many free-speech advocates lack Chemerinsky’s judiciousness. Some answer every challenge with a recitation of the First Amendment, as if its forty-five words were a magic spell that could settle any debate. Free-speech skeptics on the left can be equally predisposed to bad-faith arguments—misreading or ignoring the Constitution, dismissing the concept of free speech as inherently racist, or simply bypassing discourse and setting public property on fire.

There are better arguments. “No one is disputing how the courts have ruled on this,” john a. powell, a Berkeley law professor with joint appointments in the departments of African-American Studies and Ethnic Studies, told me. “What I’m saying is that courts are often wrong.” Powell is tall, with a relaxed sartorial style, and his manner of speaking is soft and serenely confident. Before he became an academic, he was the national legal director of the A.C.L.U. “I represented the Ku Klux Klan when I was in that job,” he said. “My family was not pleased with me, but I said, ‘Look, they have First Amendment rights, too.’ So it’s not that I don’t understand or care deeply about free speech. But what would it look like if we cared just as deeply about equality? What if we weighed the two as conflicting values, instead of this false formalism where the right to speech is recognized but the harm caused by that speech is not?”

Yiannopoulos and many of his defenders like to call themselves free-speech absolutists, but this is hyperbole. No one actually believes that all forms of expression are protected by the First Amendment. False advertising, child pornography, blackmail—all are speech, all are illegal. You’re not allowed to shout “Fire!” in a crowded theatre, make a “true threat,” or incite imminent violence. These are all exceptions to the First Amendment that the Supreme Court has made—made up, really—over time. The boundaries can and do shift. In 1940, a New Hampshire man was jailed for calling a city marshal “a damned Fascist.” The Supreme Court upheld the conviction, ruling that the words were not protected by the First Amendment, because they were “fighting words,” which “by their very utterance inflict injury or tend to incite an immediate breach of the peace.”

Are some of Yiannopoulos’s antics—say, his attempts to intimidate undocumented and transgender students—closer to fighting words than to intellectual discourse? Maybe. But the fighting-words doctrine has fallen out of favor with the courts. In 2006, the Westboro Baptist Church picketed a soldier’s funeral, carrying signs that read “Thank God for dead soldiers” and “You’re going to Hell.” Even factoring in almost seven decades of epithet inflation, this would seem more injurious than “damned Fascist.” And yet the Supreme Court ruled that the signs were protected by the First Amendment.

In the nineteen-seventies, when women entered the workplace in large numbers, some male bosses made salacious comments, or hung pornographic images on the walls. “These days, we’d say, ‘That’s a hostile workplace, that’s sexual harassment,’ ” powell said. “But those weren’t recognized legal concepts yet. So the courts’ response was ‘Sorry, nothing we can do. Pornographic posters are speech. If women don’t like it, they can put up their own posters.’ ” He drew an analogy to today’s trolls and white supremacists. “The knee-jerk response is ‘Nothing we can do, it’s speech.’ ‘Well, hold on, what about the harm they’re causing?’ ‘What harm? It’s just words.’ That might sound intuitive to us now. But, if you know the history, you can imagine how our intuitions might look foolish, even immoral, a generation later.”

In the media, and on his Facebook and Instagram feeds, Yiannopoulos tirelessly promoted his return to Berkeley. Instead of a mere lecture, he envisioned “a huge, multi-day event” called Milo’s Free Speech Week. A video had recently come to light in which he’d made some deeply ill-advised comments about pederasty. Afterward, he’d been widely condemned on both the left and the right. He seemed to hope that his Berkeley appearance would restore him to mainstream relevance, and perhaps marketability.

He posted a schedule, at FreeSpeechWeek.com, that culminated in the presentation of the first annual Mario Savio Award for Free Speech. (Savio died in 1996; his son Daniel told the Guardian that Yiannopoulos’s appropriation of his father’s legacy was “some kind of sick joke.”) When Yiannopoulos spoke privately to his influential friends on the far right, he often said, “This will be our Woodstock.” He released a list of more than twenty speakers, which included many of the usual free-speech warriors and also some surprising names, such as the secretive military-security magnate Erik Prince. In addition to Yiannopoulos, the four headliners would be Ann Coulter; Pamela Geller, a virulently Islamophobic blogger from Long Island; Mike Cernovich, a conspiracy theorist and vigilante journalist; and Steve Bannon, newly fired from his job as Trump’s chief strategist. To build anticipation, Yiannopoulos’s team made promotional videos about each headliner, in the style of an action-movie trailer. “Bannon Infiltrates Berkeley,” less than thirty seconds long, has been viewed more than thirty thousand times.

Mindful of the potential for violence, some students requested a robust police presence; others suggested that more police on campus would make them feel less safe, not more; still others demanded that the university cancel Free Speech Week. More than a hundred and fifty Berkeley faculty members and graduate students signed an open letter calling for a campus-wide boycott. Christ told me that she never considered cancelling the event. “The reputational cost would simply be too high,” she said. Reputational cost is impossible to quantify, but the literal cost to U.C. Berkeley, in security fees alone, was likely to exceed a million dollars. The university had a budget deficit of more than a hundred million dollars, with less funding coming from the state in recent years. “Would I rather devote our precious resources to more class sections, overdue building repairs, or many other things we badly need?” Christ continued. “Absolutely. But we have to make this work.” Others on campus speculated that Yiannopoulos’s real goal was to force a government-subsidized institution to expend as many resources as possible. On FreeSpeechWeek.com, there were T-shirts for sale reading “Defund Berkeley.”