Now, though, we’re doing something like the opposite. Even as mainstream media outlets scramble to cover hate movements they’d previously ignored, the guardians of the 21st century’s de facto public forum — companies like Facebook and Twitter — are shutting the radicals out.

Twenty years ago, when the Ku Klux Klan came to town, everyone knew what to do: Give the imperial wizard a permit to march, but don’t put him on the front page of the local newspaper. Free speech in the public square, but no megaphone.

A sign held outside a debate for Louisiana candidates for the US Senate, at Dillard University in New Orleans on Nov. 2. The protesters were rallying against the presence of former Ku Klux Klan leader David Duke, who participated in the debate at the historically black university.

It is a remarkable shift, one that runs afoul of centuries-old traditions of civil liberties and civil discourse. But in this vertiginous moment for the West — of fake news, far-right unrest, and ISIS-inspired slaughter — it’s gaining currency with a surprising number of legal scholars and people who study hate movements. Our liberal democracy, they seem to suggest, may be in need of an illiberal defense.

The basic argument for free speech is that, in the marketplace of ideas, the worst ideas will wither. But that model depends on old mechanisms for discarding abhorrent ideologies — newspapers ignoring the Klan march or booksellers refusing to stock Aryan Nation screeds.


On the Internet, ugly ideas aren’t discarded, they’re supercharged; one recent report found a 600 percent increase in Twitter followers of major white nationalist movements since 2012. J.M. Berger, a fellow with the International Centre for Counter-Terrorism in The Hague who wrote the report, says social media give extremists some powerful tools for growth: anonymity and an easy way to seek out people with similar interests.

“That’s the real danger,” he said in a recent interview. “If you were a radical Druid in 1950 living in Peoria, Illinois, you could go your whole life without ever meeting anybody who shared your views. Now if you’re that same person, you get online, and within an hour you can be following a hundred other radical Druids. And in two or three weeks, you can all be getting together to plant trees.”


In an essay titled “The Social Apocalypse: A Forecast,” Berger notes that ISIS, also known as the Islamic State, has become a globally disruptive force even though its members number only in the tens of thousands. He warns that a network of 1 million, a tiny sliver of the world’s population, could “wreak unimaginable havoc.”

“Without meaningful controls,” he adds, “we will see millions of people organize themselves according to racial, class, or religious identity in defiance of a generation of progress toward pluralism.”

The bulk of the radicalization happens offline. But there is mounting evidence that the Internet’s echo chambers help steer the bored and troubled toward the gruesome and violent. Dylann Roof, who is charged with massacring nine black parishioners at a church in Charleston, S.C., wrote in an online manifesto that he typed “the words ‘black on White crime’ into Google” after the Trayvon Martin case and was “never . . . the same.” The Islamic State has proven effective at luring online recruits with a graduated radicalism — building a rapport with targets, slowly introducing extreme ideas, and then urging real-world action.

“For the first time, I felt I was not only being taken seriously about very important and weighty topics, but was actually being asked for guidance,” wrote Ali Amin, a lonely Virginia teenager drawn in by ISIS sympathizers, in a letter to the judge who sentenced him to 11 years in prison for abetting terrorists.


Legally, stifling the expression of radical groups is a nonissue when today’s public squares are privately owned. Facebook and Twitter can block child pornographers, white supremacists, and jihadists as they see fit. Lately, they’ve made a concerted effort to crack down on ISIS’s online activity.

In August, Twitter said it had suspended 360,000 accounts promoting terrorism since the middle of 2015. And just this month, Twitter, Facebook, YouTube, and Microsoft announced a joint database that will help them track and take down “violent terrorist imagery or terrorist recruitment videos.”

Censoring one of the world’s most reviled groups isn’t a tough sell. As University of Chicago law professor Eric Posner argues, in a Slate essay calling for a law against accessing websites that glorify or promote ISIS, the terrorist organization isn’t adding much to the marketplace of ideas. “Just what is it that we can learn from ISIS?” he writes. “The social value of beheading apostates? The finer points of crucifixion?”

Berger, of the International Centre for Counter-Terrorism, says white nationalism will pose a far stiffer test because it’s deeply embedded in Western culture. One study of 10,000 Donald Trump supporters on Twitter found more than one-third followed at least one of 10 white nationalists, including former KKK leader David Duke and Ann Kelly of the White Genocide Project.


Figures like Richard Spencer, a buttoned-down spokesman for the so-called alt-right, a white nationalist offshoot of conservatism, can make a stronger moral argument than ISIS against online censorship. In an online video posted shortly after Twitter took down his account and those of several other alt-right figures, Spencer complained that he hadn’t harassed anyone — unlike Milo Yiannopoulos, the conservative provocateur suspended from the service after directing a torrent of Internet hate at “Ghostbusters” actress Leslie Jones.

Analysts caution that suppressing an idea, making it taboo, can imbue it with a certain power. In Spencer’s video, titled “Knight of the Long Knives” — a reference to a Nazi purge that consolidated Hitler’s power — he moved to exploit the drama of a movement under siege. “I am alive physically,” he said, “but digitally speaking, there has been execution squads across the alt-right. . . . There is a great purge going on.”

Mike German, a former FBI agent who infiltrated neo-Nazi and antigovernment militia groups, says confining dangerous ideas to dank basements and grimy garages empowers the violent elements of extremist groups. “They can say. . . ‘See, that’s why we have to use these criminal methods, because the First Amendment doesn’t work for us,’ ” he says. “‘They’re afraid of our ideas.’ ”

On the Internet, though, blocked speech often pops up elsewhere. Spencer, in his video, suggested he might simply move from Twitter to another social media network called Gab. That sort of quick migration is often held up as an argument for the futility of online censorship.


But Gab is no Twitter. Pushing Spencer there means pushing him closer to the margins. And that may be the most compelling justification for suppressing hate speech in the Internet age. In the end, this is a soft censorship — a marginalization, but not a blotting out, of extreme views. And that is something the culture has long tolerated.

Is relegating the alt-right to Gab so different than relegating the Klan to page B3 of the newspaper?

Shortly after Trump’s election, Spencer and a small group of white nationalists gathered at a Washington hotel to bask in their newfound influence. There were panel discussions and after-dinner speeches. Reporters were there in force. And when the Los Angeles Times tweeted out its story on the confab — “Meet the new think tank in town: The ‘alt-right’ comes to Washington” — the Internet revolted. “Calling these white nationalists a ‘think tank’ is atrocious,” tweeted radio and television commentator Roland Martin.

But the actual article was more nuanced than the tweet implied, suggesting that “today’s nationalists [are] picking up where David Duke left off when the former Klan imperial wizard shed his robes to enter politics in the early 1980s.”

“This is how you sneak these ideas into the mainstream,” said Heidi Beirich, who tracks hate groups for the Southern Poverty Law Center, in the piece.

Beirich, speaking with the Globe a couple of weeks later, said there needs to be more — not less — mainstream media coverage of extremism in the age of Trump. “Given that Trump won, and won on a campaign of vilification . . . we’re probably going to see [other] candidates who are willing to make these arguments in an attempt to win election,” she said.

Editors and publishers have long feared that any publicity for radical movements would encourage their spread. But Beirich argues that social media’s amplification of hate speech and conspiracy theories only reinforces the need for traditional journalists to scrutinize the extremists.

Still, the traditional media’s influence extends only so far. Ultimately, reining in hate may require a public revolt against the social networks where it lives.

Twitter is already feeling a backlash. The service’s basket of deplorables doesn’t just include neo-Nazis. There are many other anonymous trolls, too — misogynists and garden-variety racists — and more and more of their targets are backing away from Twitter.

The loss of those voices is a speech suppression of its own.

David Scharfenberg can be reached at david.scharfenberg@globe.com. Follow him on Twitter @dscharfGlobe.