This is what was on Thomas Chatterton Williams’s mind when he decided to write a short letter on the risks to liberalism and open discourse and get some like-minded thinkers to sign on.

He was thinking of the Poetry Foundation, whose leaders resigned after their four-sentence statement in support of Black Lives Matter was deemed too tepid by 1,800-plus petition-signers. And the National Book Critics Circle, whose board imploded over its own attempt at such a statement.

He was thinking of David Shor, a political scientist who was fired after tweeting about a study suggesting that violent street protests helped tip the 1968 election to the GOP; and Colin Kaepernick, a quarterback who was shunned from the NFL after his anti-racism activism ran afoul of conservative fans.

“You had people calling for greater control and less permissiveness in expression all across the political spectrum,” said Williams, a cultural critic who has written extensively about race.

So he and four other writers penned “A Letter on Justice and Open Debate” — warning that “the free exchange of information and ideas” was being compromised by “an intolerance of opposing views, a vogue for public shaming” and “the tendency to dissolve complex policy issues in a blinding moral certainty.” Published July 7 by Harper’s, it was signed by 153 notable figures from academia, media and culture, including Noam Chomsky, Gloria Steinem, Margaret Atwood, Salman Rushdie and Wynton Marsalis.

The response was swift, bitter — and, for many of them, unexpected.

Far from being embraced as a high-minded salute to free speech and the bracing effects of political discourse, the letter was blasted for messages its authors swear were never intended. Some saw in it a sinister attempt to push back against a national conversation about racial justice. Transgender activists saw in it a veiled assault on their community. Liberals sensed a tired anti-PC complaint. A couple signers asked to have their names removed after they found themselves sharing space with ideological enemies.

But most withering of all were the cynics who scoffed that the letter reflected no more than the petty, wounded feelings of its celebrated signatories — suddenly forced by social media to contend with criticism from the little people and perceiving it as a threat to their own free speech.

Well, at least they got everyone’s attention, Williams reasoned. “Three paragraphs don’t resonate around the world like that if they’re just a straw man,” he said.

Some saw the backlash coming from miles away. Bari Weiss almost certainly did — though it's doubtful that would have ever stopped her from signing it.

When the letter appeared, the New York Times opinion writer was one week away from dramatically quitting her job, with an open letter of her own, blasting Times editors whom she saw as caving to Twitter critics insistent on a certain left-wing orthodoxy and Times colleagues she claimed bullied her for her self-described centrist views.

But then again, Weiss has always seemed to relish the fight. Lamenting “cancel culture” was part of her brand at the Times. She championed the work of the “intellectual dark web,” whom she believed had been shunned by mainstream media for their views. And after online critics called her out for errors in her work, she portrayed it as an assault from a left-wing “mob.”

Lately, she has been organizing secret dinners at Manhattan’s Comedy Cellar for like-minded personalities to hash out their disagreements in private. One such gathering ended up at the Brooklyn home of writer Katie Roiphe, merrily dubbed a “Thought Crimes” party, where everything that was discussed, as well as the list of attendees, was off the record. The party went to 2 a.m., Roiphe said, and everyone had a great time.

Yet some others who agree with Williams’s message were far less inclined to Weiss’s combative approach.

“The timing is wrong,” explained Robert Reich, the economist and former labor secretary, who appreciated the letter’s spirit but declined to sign it.

The letter landed amid several controversies raising questions about the boundaries of acceptable political disagreement. There was the June 7 resignation of New York Times editorial page editor James Bennet after a staff uproar over an op-ed in which Sen. Tom Cotton (R-Ark.) advocated sending the military into cities where protests had turned violent, which Bennet later acknowledged he hadn’t read before publication and said did not meet the paper’s standards.

And the same day as Weiss’s resignation, the semi-conservative writer Andrew Sullivan created almost as much of a tizzy when he said he was leaving New York magazine because the staff “no longer want to associate with me.” (The magazine’s editor, David Haskell, explained it more dryly: “Publishing conservative commentary . . . in 2020 is difficult to get right.”)

But it also hit amid the racial justice protests flooding America’s streets — a movement initially focused on police brutality that ignited a larger reckoning in cultural and media organizations, where long-simmering complaints about insensitivities and pay disparities have spilled into public view.

It’s what Reich considers “an incipient movement of people of color [who are] teaching the rest of America about systemic racism, and women [who] are courageously opposing systemic harassment.” And so he feared that the letter would “run the risk of suggesting, even indirectly, that they are wrong-headed or overly sensitive.”

In fact, many readers perceived that very suggestion in the letter’s third sentence. It argued that “this needed reckoning” (and truly, it is indeed needed, the authors hastened to add) has “intensified a new set of moral attitudes . . . that tend to weaken our norms of open debate and toleration of differences in favor of ideological conformity.”

Jill Abramson’s reason for not signing? “I thought it was part of an anti-wokeness campaign, backlash clothed as free speech,” the former New York Times executive editor said bluntly.

“Fatuous, self-important drivel,” wrote HuffPost editorial director Richard Kim, who also declined to sign, “that would only troll the people it allegedly was trying to reach.”

Part of the letter’s problem was its vagueness — its failure to cite by name the people its signatories felt had been wrongly stifled, shamed or silenced:

“Editors are fired for running controversial pieces; books are withdrawn for alleged inauthenticity; journalists are barred from writing on certain topics; professors are investigated for quoting works of literature in class; a researcher is fired for circulating a peer-reviewed academic study; and the heads of organizations are ousted for what are sometimes just clumsy mistakes.”

Which cases, exactly, were they referring to? Those who knew, knew. Or at least they thought they did. Everyone else was left to find meaning in the names of the 153 people who signed the letter — some of whom had already waded deep into the more controversial waters of the current political discourse and made a few enemies in the process.

Such as: J.K. Rowling, best known as the author of the Harry Potter books but who has lately raised concerns about the increasing number of children seeking gender-affirming care and recently griped that the phrase “people who menstruate” (to describe women as well as transgender men) was demeaning to women — drawing outrage from some trans activists, who then assumed, because of her signature, that the entire letter was a broadside against them.

Or signatory Steven Pinker, a Harvard psychologist whose provocative comments on the biological differences between men and women, and their effect on intelligence, has drawn an intense backlash. There was also a petition signed by 550 academics to oust him from the Linguistic Society of America’s roster of distinguished fellows because of his tweets arguing that race is not a significant factor in police shootings, plus a handful of others they saw as “drowning out the voices of people suffering from racist and sexist violence.”

And then, of course, there was Weiss herself, who had agitated many on the left with columns cheering cultural appropriation and mocking what she saw as a progressive “caste system” based on which identity groups can claim to have been most oppressed.

As it turned out, even the letter's authors had been moved by different things when they wrote it. If the Poetry Foundation was on Williams's mind, George Packer was thinking about Bennet.

His resignation under fire “and the way in which it cast a chill at the New York Times, worried us,” Packer said.

He also mentioned the case of Alexis Johnson, one of the Pittsburgh Post-Gazette’s few black reporters, who was barred by editors from covering racial-justice protests for a wry tweet they said showed bias (she had posted a photo of a debris field left behind after a country-music show with a joking comparison to the recent hype about looting).

A writer for the Atlantic, Packer wants to make clear that the point was to stand up for other people facing intolerance: “There was nothing personal about this letter or about the experience any of the five writers had had.”

Packer said they intentionally set out to get signatures from an eclectic group of intellectuals — “a list that would be so diverse in both identities and political views that no single name could define it, and no one could dismiss it as a clique of the usual suspects,” he said. “I wanted a list that would make people stop and ask, ‘What are all these people doing together? What belief do they all share?’ ”

Williams asked conservative economist Glenn Loury, a professor at Brown University, who was flattered but declined: As a conservative, he felt that the debate was “kind of inside the club” — a club for liberals, that is — “and I’m not really a member of the club.”

The authors, Packer said, didn’t want to appear to be critiquing the protests against police brutality. But “you couldn’t wait until someone would not mistake your purpose, because someone will always mistake your purpose.”

Three days later, a group of more than 150 journalists, academics and writers signed a response letter arguing that the Harper’s manifesto didn’t address the power dynamics at play and “how marginalized voices have been silenced for generations in journalism, academia, and publishing.”

“Black, brown, and LGBTQ+ people — particularly Black and trans people — can now critique elites publicly and hold them accountable socially,” reads the response. “This seems to be the letter’s greatest concern.”

“I’m kind of confused by that criticism,” said Williams, who is biracial. He called the list of signatories “extraordinarily diverse,” including Reginald Betts, an African American poet and memoirist who spent eight years in prison for stealing a car at age 16; Orlando Patterson, a Jamaican-born Harvard sociologist known for his work on issues of race; and Kian Tajbakhsh, an Iranian American professor of urban studies at Columbia, who was held for years in an Iranian prison before returning to the United States.

“The idea that it’s a bunch of white elites has become a rhetorical talking point that’s just not an honest reading of what we put together,” said Williams.

While the Harper's letter doesn't explicitly blame "cancel culture," many readers saw it as the subtext — a big part of the debate roiling elite cultural institutions.

For some, “cancel culture” is the specter of online mobs advocating for someone to get fired over anything from an old tweet to an innocuous statement that doesn’t conform to some emerging progressive ethos. Others argue there’s no such thing — that the phrase itself is an attempt to dismiss the young or minority or LGBTQ groups using social media to hold the powerful accountable.

In some liberal circles, the mere mention of “cancel culture” will set teeth on edge, especially now that conservatives are quick to lob the accusation. When 80 Pittsburgh Post-Gazette staffers were also barred from protest reporting because they had tweeted in support of Jones, the saga became national news, and their editor went on Fox News blaming “the Twitter mob” — a classic “cancel culture” euphemism — for portraying him as racist.

Liberal New York Times columnist Michelle Goldberg signed the letter after a mention of “cancel culture” was taken out of it. The specific problem, she wrote, are the cases where activists don’t just challenge a person’s faulty argument but push for their firing. “It’s the involvement of human resources departments in compelling adherence with rapidly changing new norms of speech and debate that worries me the most.”

New York magazine columnist Jonathan Chait didn’t sign the letter, but only because he has a policy against open letters. He agreed that the left “has been adopting these rules of discourse around identity questions that make it impossible to contest any charge of racism or sexism.” Those charged, he said, “have no choice but simply move on to the apology section of the conversation.”

Masha Gessen, author of several books on autocracy and totalitarianism, was not asked to sign the letter — perhaps because Gessen was already on record disputing the authors’ suggestion that quashing debate through social pressure is as ominous as government repression. “Totalitarian ideology had the power of the state behind it,” Gessen wrote in the New Yorker in June. By contrast, “protesters in the streets of American cities and the journalists who support them are not backed by state or institutional power, but just the opposite: In every instance, they are in confrontation with it.”

Yascha Mounk, who did sign the letter, endorses Gessen’s distinction, but he warns that the left should be worried about stifling free speech, because he’s seen how it can get worse. An expert in populism and illiberal democracy at the Johns Hopkins School for Advanced International Studies, he said his grandparents fought for a communist regime in Poland that turned against them and expelled them in anti-Semitic pogroms. He understands how noble-seeming movements can go bad. He sees President Trump’s authoritarian tendencies poisoning the discussions at the opposite end of the political spectrum.

Days before the Harper’s letter appeared, Mounk launched an online publication called Persuasion, dedicated to open debate. More than 25,000 people have signed onto the email list, far beyond his expectations. He wants it to be a haven for those who feel muzzled by what he sees as the stifling of speech among major mainstream publications.

Writers such as . . . Bari Weiss or Andrew Sullivan, perhaps?

Actually, both seem to have found safe spaces of their own already. Sullivan announced he is returning to an independent blogging platform to write. Weiss, in an email, said she is hopeful to find a way to help satisfy a “tremendous hunger for honest journalism and good-faith debates.” No specific destination yet, but friends say there are investors eager to back her next project.

A previous version of this story gave an incorrect last name for Alexis Johnson of the Pittsburgh Post-Gazette. The error has been corrected.