Yesterday I checked my Twitter feed and learned that Roseanne Barr had finally blown herself up.

Up all night tweeting about Soros and Clinton conspiracy theories (including a bizarre exchange with the cool-headed Chelsea Clinton about whether her husband is a member of the Soros family), Barr capped off her literary output with a tweet aimed at Chicago businesswoman and former senior Obama advisor Valerie Jarrett: “Muslim brotherhood & planet of the apes had a baby=vj.” By two o’clock, Eastern Standard Time, she and several hundred other people working on her television show, Roseanne, were unemployed.

Shocking? Yes. Unexpected? No — not for anyone who has followed Barr for the last 30 years, and watched her slowly unravel since 2013. I’m not talking about her outspoken support for Donald Trump, which makes her unusual in the film and television industry, but not unique. It is her undiluted rage and attachment to the President’s fringiest partisans, their conspiracy theories, and their racism that has been a train wreck happening in slo-mo. A woman who, in 1990, broke about a million stereotypes about femininity by grabbing her crotch and spitting in front of a national audience, following one of the most tuneless renditions of the National Anthem ever, Barr’s views and social media persona have become indistinguishable from those of the average alt-right Internet troll.

The Jarrett tweet is not unprecedented either. On December 22, 2013, Barr tweeted that Obama National Security Advisor Susan Rice “is a man with big swinging ape balls.” She has spread and amplified some of the most noxious far-right conspiracy theories and memes in existence, including QAnon, a fictional government insider born on the 4chan message board; the Clinton family’s invented links to child sex trafficking and a “deep state” conspiracy to depose Trump; and an elaborate slander that George Soros, as an 11 year-old in Nazi-occupied Hungary, assisted in the murder of Jews and founded his fortune on their stolen wealth.

For whatever reason — and let me emphasize, Roseanne Barr was this person before ABC rebooted the show and has been posting weird tweets throughout the 2017-18 season — all hell broke loose in Hollywood yesterday. Perhaps it was because the writers were scheduled to return that day to begin Season 2 and this was the time to pull the plug if it was going to be pulled; or perhaps it was that key figures on the show were already unhappy with the star’s erratic behavior. Almost immediately after the Jarrett tweet, as ABC execs were in emergency meetings, consulting producer Wanda Sykes, an African American woman, announced on Twitter that she would “not be returning to @RoseanneOnABC.” Co-star Sarah Gilbert, who plays Barr’s daughter, tweeted that the views Barr had expressed that morning were “abhorrent and do not reflect the beliefs of our cast and crew or anyone associated with our show. I am disappointed in her actions to say the least.”

The famous and the non-famous jumped in, making it almost impossible for ABC to not act. British journalist Piers Morgan tweeted that Barr is “a vile racist imbecile.” Joe Scarborough, host of MSNBC’s Morning Joe, announced that there was no apology sincere enough to justify ABC “turning a blind eye to this bigotry and airing another second of her show.” And in a bizarre twist, only possible on social media, an old  image of Roseanne Barr in a Hitler mustache taking “burnt `Jew cookies'” out of a large oven, acquired a new life as trolls from the left went on the attack. “These are not unfortunate misunderstandings,” one tweeter admonished. “This is who #RosanneBarr is.”

There’s nothing like fighting hate by recirculating hate, is there? Welcome to the Internet.

At 11 a.m. Pacific Time, ABC announced that Roseanne would be canceled: soon after, the first nine seasons of the show that were being re-run on other networks had also been pulled. This triggered predictable outrage on the part of Barr’s fans, Trump supporters in the main, who saw the cancellation as yet another example of political correctness run amok,  and a new chapter in the repression of conservative free speech. In response to one of Barr’s jumbled and contrary apologies, this one an admission that her out-of-control behavior had cost other people their jobs, one Trump supporter asserted that it served the cast and crew of the rebooted Roseanne right for abandoning the star. “I don’t feel bad for them at all,” @PROtruth (whose banner asserts that “Truth is the new hate speech”) tweeted. “They’ve known her for long enough to know she is no racist and they threw her under the bus instead of having their non-racists’ co-stars back! #NoRespect”

As of today, Roseanne has removed the offending tweet, apologized, and issued a series of increasingly angry and irritable explanations.  In one of them, she claims to have been up all night under the influence of the sleeping pill Ambien:

This is, I think, what is called “taking responsibility.” And yet — not? Because simultaneously, Barr has been rewarding her angry supporters by retweeting their defenses of her. Bill Mitchell, a North Carolina businessman who seems to spend an outsized amount of time using Twitter to promote Trump’s policies, argued that not only was Barr’s tweet insignificant — it wasn’t even racist, according to liberal and left ideology (as caricatured by the right!) “I thought Muslim Brotherhood’ was supposed to be a `good’ thing,” he tweeted, using Trumpian scare quotes, “and Liberals say we are descended from apes. What am I missing here?”

I have to admit that I did not have a dog in the fight over whether Roseanne ought to have been revived as a working-class sitcom newly relevant to the age of Trump, or whether ABC ought to have given Barr a new platform, given her shift from iconoclast to third-party populist gadfly to full-out wacko. But it was a good gamble, and one that was paying off, if the ratings are any evidence. I never watched the original Roseanne until long after its nine year run, beginning on October 18, 1988, and ending on May 20, 1997, but when I did, it was clear to me that it had taken television comedy to to a new level in tackling the controversies that were accompanying a rapidly changing society.

Roseanne was always a very political show, in a genre — humor — that is highly political by its very nature. American Studies scholar Allison Kibler has pointed out that resisting “racial ridicule”  has been part of how ethnic minorities in the United States resisted exploitation and discrimination and made claims to full citizenship. Comedy is also an offensive weapon, particularly when it is — well, offensive.  As historian Joyce Antler notes:”Women and minorities used humor to break taboos, challenging authority and subverting role norms. `Comedy is power,'” Antler explained, quoting the legendary standup comedienne Joan Rivers. “`The only weapon more formidable than humor is a gun.'” Sascha Cohen, who is writing a book about American comedy, agrees, but emphasizes that humor does not always work in service to justice. “Marginalized groups have weaponized humor as a form of resistance and retaliation towards dominant groups, powerful institutions, and the status quo,” she said. “At the same time, it has also been used to `punch down’ at cultural scapegoats and underdogs, as a way for the privileged to shore up their status and identity.”

These explanations highlight why sitcoms are so important at moments of social change in the United States, and were particularly effective at the end of the twentieth century, when the sexual, racial and cultural revolutions of the 1960s and 70s were transforming citizenship. In the 1970s, the great James L. Brooks and Allan Burns (The Mary Tyler Moore Show), Norman Lear (All in the Family and Maude), and Larry Gelbart (Mash) remade the genre of the sitcom itself around resistance to, and the awkwardness of, new social rules and expectations. An interesting feature of these shows was that intolerance often was the whole joke, but to make that clear, the audience had to be cued when to laugh and who to laugh at. For example, Archie Bunker’s rants against “fags,” “the colored,” immigrants, and hippies, were accompanied by a laugh track. Each epithet coming out of Archie’s mouth was followed by a burst of laughter, which then crested in prolonged mockery at the end of his rant, as the camera panned out to show the rest of the cast staring at him wordlessly. We, the audience, were not laughing with Archie, we are laughing at him — as his relatives would too, if they dared.

Serious topics like women’s liberation, abortion, affirmative action and racial integration, divorce, heterosexual sex outside of marriage, and homosexuality became increasingly normal fare for comedy by the 1970s and 80s, often with a single character who would represent the appropriate attitude towards these seismic cultural changes. The Mary Tyler Moore Show was not only one of the first shows to feature an unmarried career woman, but Mary herself was also often a self appointed Equal Employment Opportunity Commission officer, lecturing the men around her about their sexism, inappropriate behavior, and outdated belief systems. In the clip below, Mary explodes in outrage at her boss, Lou, because of his antiquated views about female sexual virtue. But the laugh track encourages us to take both characters seriously by punctuating both their lectures with hilarity. Here, it is not the ideological position of either Mary or Lou that is exclusively funny, but the yawning gap between Lou’s sexist views about female sexual morality, and Mary’s defense of women’s sexual freedom, their inability to hear each other, that is the stuff of the joke.

By the late 1980s, a new generation of shows, including Roseanne, took sitcom social change to the next level. Murphy Brown (which is said to be under contract for a revival next season), Will & Grace (already revived), Ellen, and Friends were among these shows, as was Larry David’s Seinfeld, a “show about nothing” that is also in a sort of revival as Curb Your Enthusiasm, a show that is also about, well, nothing — and that stars Larry David as himself.

Roseanne stands out as one of the few shows in this group to have looked at the late twentieth century culture wars, not from a cosmopolitan sensibility, but as a history from below. In its depiction of a struggling, working class family living in a post-industrial Midwestern town, Barr created a new platform where issues that were more or less banned from television — blue collar struggles, fatness, and homosexuality, — could be discussed openly, contentiously and crudely, the characters permitted to grow into a more complex present.

Like a number of the new stars that had emerged from the world of stand up comedy, Barr slipped back and forth between her real life and a character based in her own life and history as a white, working-class woman. Unlike Archie Bunker, however, Roseanne was the moral center of the show, one who often led the way by making mistakes, articulating her prejudices, and adapting to new realities with good humor. Over the course of the first few seasons, as the Conner family faced one economic setback after another, it was Roseanne’s courage, humor and fundamental decency that gave the audience confidence that she could change, no matter the challenge.  In the season 5 episode “Ladies Choice,” filmed during a 1992 presidential campaign in which Bill Clinton promised to allow lesbian and gay soldiers to serve openly and broadcast a week after election day, Roseanne and sister Jackie (Laurie Metcalf) navigated their friend Nancy (lesbian performance artist Sandra Bernhard) coming out, which Nancy only does as a final resort when they insist on setting her up with a man.

In a subsequent scene, Roseanne broaches the subject of lesbianism with her college-bound daughter Darlene (Sarah Gilbert), who responds with a snooty, “Mom, I already pretty much know about lesbians, and what I don’t know, you’d be too embarrassed to tell me.” When Roseanne tells her about Nancy, it is the sophisticated Darlene who is shocked. “Whoa! How’d you find out?” she blurts. “Did she tell you?”

Roseanne gets her revenge. “NO!” she says smiling cheerfully at her daughter. “We saw the`I’m a big old dyke’ bumper sticker on her car!” The outraged Darlene stalks off, leaving it unclear whether she is embarrassed by falling into her mother’s trap or enraged by Roseanne’s politically incorrect use of the word “dyke.” Significantly, Darlene’s retreat triggers the laugh track, leaving Roseanne in the kitchen to enjoy her victory. In All in the Family, the bigot himself is the joke; in Mary Tyler Moore it is the struggle over social change itself that it funny; but by Roseanne, it was turning the tables on the snobbery of supposedly educated people that was the joke, winning the audience’s sympathy for Roseanne’s practical approach to difficult problems.

Jokes are, of course, in the mind of the beholder: without a laugh track, “big old dyke” is just a mean put down, and even with a laugh track, an edgy line like that succeeds because we already believe Roseanne is a good person. But her behavior on Twitter in recent years makes that an increasingly difficult belief to sustain. One of the things I have noticed about Roseanne’s Twitter feed is that, in recent weeks, when she has been called out for some of her viler tweets, she identifies them as jokes that the critic clearly did not get.  This was part of her “apology” to Valerie Jarrett:

Did she really intend her attack on Jarrett to be a joke? Or was this the real Roseanne, her rage fueled (or not) by Ambien? I’m not sure we will ever know. As of this afternoon, buoyed by the number of supporters tweeting encouragement, Barr is walking back her contrition. If you were trying to decide whether to forgive her or not, you should probably wait.

But if the Valerie Jarrett tweet reflects who she really is, and I think it does, it may be the medium, not the message, that is the source of Barr’s calamity this week. How would we know that such an ugly, racist utterance was supposed to be a joke?Did she forget that life has no laugh track? Could a similar comment actually be funny if said in character, framed by the many devices television comedy has to offer? Could it provide an opening for a radically moral anti-racist plot line?

You’ll have to wait for next season for an answer to these questions: right now, the only channel Roseanne Barr has access to is Twitter.

In an earlier version of this essay, I referred to the Hitler image as Photoshopped: I stand corrected. It was a real photoshoot done for the satire magazine Heeb in 2009.

Claire Potter is professor of history at The New School, and Executive Editor of Public Seminar. You can follow her on Twitter