Of all the memes circulating in the weeks since the October 7 massacre in Israel, the most startling one was sent to me by A., an attorney in the Los Angeles County Public Defender’s Office. The cartoon, which A. came across in the Instagram feed of a deputy attorney at a neighboring office, depicts a group of black-clad soldiers, perched on the rim of a barrel-shaped structure, aiming into the opening below. A Palestinian flag and a ball of fire rise from the center of the barrel, while a pool of blood seeps from its base. The word “GAZA” looms in the background in all caps, but it’s the symbol adorning the cylinder that is most eye-catching: a Star of David interlaced with a swastika.

“She actually posted a swastika with a Jewish star,” says A., who asked to remain anonymous for fear of professional retribution.

Like most public defenders, A. considered herself politically progressive. Progressives make up a relatively small percentage of the population, but they have had an outsize influence on public debate in recent years, partly because of their shared sense of conviction and moral superiority. From gay marriage to civil rights to climate change, being on the right side of history is understood by devout lefties to be not just easy but simple, so much so that it can be expressed in one of the three-to-five-word slogans on those ubiquitous IN THIS HOUSE, WE BELIEVE signs: BLACK LIVES MATTER, women’s rights are human rights, love is love, no human is illegal, and so on.

Notably, these signs never explicitly mention Jews, but surely a political ideology founded on compassion for the oppressed would accommodate a minority that has been persecuted for millennia. And in a world where making a statement on the current thing is increasingly considered non-optional—as the slogan says, Silence is violence—many progressives expected that the events of October 7, in which Hamas terrorists killed more than 1,400 Israeli civilians and kidnapped at least 230 more as hostages, would precipitate an outpouring of sympathetic postings on par with those following the killing of George Floyd or Russia’s invasion of Ukraine.

Instead, they got a wake-up call.

“People I thought I got along with, I’m seeing them post things that are horrible and ignorant,” says A., who now describes herself as “politically homeless.” “And maybe they don’t know, and that’s fine, but how do you explain this to everybody?”

She’s not alone in her bewilderment. The conflict in Israel has become perhaps the first major wedge issue among millennial and Gen Z progressives, causing rifts in institutions, social groups, even individual households.

Being on the right side of history is understood by devout lefties to be not just easy but simple, so much so that it can be expressed in one of the three-to-five-word slogans on those ubiquitous IN THIS HOUSE, WE BELIEVE signs.

K., a 41-year-old lawyer who was born in Iran to a Jewish mother and a Muslim father, was shocked to find himself at odds with his wife, a daughter of Afghan immigrants, in his sympathies for Israel.

“I am firmly in the camp that Islamic Fundamentalism is a cancer that needs to be eradicated. She thinks Israel is committing war crimes in Gaza. And it’s clear to me that her social media feed is giving her vastly different information than what my feed is showing me,” he writes via e-mail. “I know she loves my family and has a lot of Jewish friends. But it’s clear that a lifetime of hearing tropes about Jews has affected how she feels about this conflict.”

Those Jewish tropes have become a central point of contention in this debate, fueled by a messy discourse that tends to conflate the Israeli government with its citizens, and sometimes with Jews worldwide. Jewish members of the Los Angeles Public Defender’s Office who tried to organize a D.E.I. training focused on American anti-Semitism in 2021 were shut down by colleagues who demanded the presentation be expanded to address the issue of Palestine. When Senator Bernie Sanders posted last week in observation of the anniversary of the Pittsburgh massacre at the Tree of Life synagogue, in which 11 congregants were murdered by a gunman shouting, “All Jews must die,” he was inundated with “Read the room” replies from Palestine supporters who felt he was snubbing the situation in Gaza.

One can certainly be a critic of Israel without being an anti-Semite. But given that the perpetrators of the October 7 massacre weren’t exactly at pains to make this distinction—footage from the day of the attack included one Hamas fighter calling his parents and proudly announcing, “I killed 10 Jews with my own hands!”—the progressive response has been strikingly muted. Many institutions have chosen to release statements that not only decline to express sympathy for murdered Israelis but suggest that the violence was an understandable if not justifiable outburst against oppression, a position aggressively taken up on social media by many individuals for whom Palestine is their new pet cause.

Randie Shapiro, a registered nurse who describes her Jewish identity as something “worn on the outside,” says she felt rattled when a friend’s teenage daughter began posting pro-Hamas memes on Instagram in the wake of the attacks. “I would never say anything about it. I’m a grown-up,” she says. But Shapiro’s own kids were posting in support of Israel, and soon the families were in conflict. “This child started reaching out to my older child, saying, Are you a Zionist like your sister?”

Shapiro contacted the girl’s mom, a longtime friend, to smooth things over. Instead, the situation exploded. Shapiro and her friend had a falling out (“Enjoy the war,” the friend said via text), while the friend’s daughter, who once attended Passover dinners at the Shapiros’ home, began inundating Shapiro with pro-Palestinian messages on Instagram before blocking her. The loss of her friend, Shapiro says, was painful—but this was infuriating. “The audacity of this child,” she says.

When Senator Bernie Sanders posted last week in observation of the anniversary of the Pittsburgh massacre at the Tree of Life synagogue, he was inundated with “Read the room” replies from Palestine supporters who felt he was snubbing the situation in Gaza.

Youthful audacity has been something of a hallmark of the Israel discourse. Americans under 25 have only ever known Israel as the seat of Netanyahu’s increasingly far-right regime, and their reflexive sympathy for Palestinians often betrays a lack of basic knowledge of the history and cultural issues into which they’re wading. At its most absurd, this translates to mockable spectacles such as the “Queers for Palestine” movement. (Homosexuality is illegal in Gaza, and many gay Palestinians even seek refuge in Israel.) A sizable contingent of the young people posting “from the river to the sea” memes on Instagram would probably struggle to identify said river on a map, or even to name it.

But even the best educated young activists are committed to understanding the conflict through the left-wing framework of power, privilege, and decolonization, which casts Israel as a racist aggressor against its poorer, browner neighbors in Gaza. M., a 23-year-old Yale graduate who works in publishing, sees the plight of Palestinians as morally and thematically entangled with Black Lives Matter. “Those movements are all part of a similar eco-system of global racism and settler colonialism,” she says.

So, it seems, does Black Lives Matter itself, whose Chicago chapter approvingly tweeted an image of a Hamas paraglider just days after the October 7 massacre. The tweet was subsequently deleted, but the organization reaffirmed its solidarity “with Palestine [and] the people who will do what they must.”

Patrick Smith, a 37-year-old Lebanese-American artist, was horrified to see images of the paraglider circulating among his friends and fellow artists on social media. “I can’t think of anything more antithetical to art than Hamas,” he says. Artists and Islamic fundamentalists do make for strange bedfellows, given the latter’s penchant for destroying artifacts and assassinating artists who offend their sensibilities.

“I think a lot of people, myself included, were in denial about how bad the anti-Semitism problem was on the left. Once the paraglider memes came out, it was pretty hard to deny. If I know someone who thinks that was a good thing or some form of resistance, then we’re clearly living in totally different moral universes.”

Smith is also worried that the barrier between those universes is becoming less permeable as stridency becomes more fashionable. As a younger person, he says, “I was 100 percent indoctrinated into hating Israel.” But he had Jewish friends in his life whose views he eventually came to find persuasive. He fears the current vogue for radicalism is making it infinitely harder for its adherents to ever revisit their views. “If I was wearing an Arafat headscarf and screaming, ‘River to the sea,’ I would alienate the very people who helped me see this situation clearly. That’s a different level of indoctrination, and it’s what I’m seeing right now with people in my social circle. I have no idea how someone gets out of that.”

I don’t know, either. What I do know is that this kind of escalating radicalization is a frequent by-product of societies in which the older and more experienced abdicate their authority to the young, a recurrent phenomenon in times of political turmoil. It was 1968 when the movie critic Pauline Kael observed that “so many people are beginning to treat ‘youth’ as the ultimate judge—as a collective Tolstoyan clean old peasant. They want to be on the side of youth; they’re afraid of youth.” And we’re afraid of it, too, aren’t we? The kids have the power to cancel us, and the tools with which to do it.

“I think a lot of people, myself included, were in denial about how bad the anti-Semitism problem was on the left. Once the paraglider memes came out, it was pretty hard to deny.”

“Everything is fandom and anti-fandom,” says Leigh Stein, an expert on digital culture in general and TikTok in particular. TikTok is perhaps the purest distillation of human tribalism as filtered through the cheesecloth of the Internet, and viral posts there tend to follow a particular pattern: they’re short, they use trending audio clips, and they indulge in what Stein calls “merry mischief-making,” which is to say, they mock the members of the opposing side.

That format doesn’t change with the seriousness of the subject matter. Consider the platform’s most popular Israel posts: in one video addressed to Israel supporters, a middle-aged British fashion influencer lip-synchs a line sung by Jennifer Coolidge in A Cinderella Story—“You’re not very pretty, and you’re not very bright”—before wrapping herself in a kaffiyeh. In another, an explainer video about how Israel pulled out of Gaza in 2005 is interrupted by Andrea Delaney, a mom of three from Iowa who otherwise mainly posts content about how to shop for dye-free foods. “I know who else should have pulled out: your dad,” she says. This latter video has been viewed 1.6 million times.

This is the power of fandom as a medium for communication; it is also why the people who are most engaged on social media may be the least informed about the topics they engage with. Nobody cares that Israel did, in fact, pull out of Gaza in 2005. This isn’t about accuracy, it’s about seeing your team win—or, more importantly, seeing your rival humiliated.

And if the influence of decolonization theory is one reason why Israel has become such a wedge issue, the emergence of an information landscape driven as much by social media as by old-fashioned reporting is surely another. Members of Gen Z don’t just post on TikTok; they use it as a search engine, a place to think out loud as well as to be told what to think. Imagine trying to understand one of the most complex geopolitical issues in all of human history through such a warped lens. On TikTok—and increasingly, on social media in general—nuance is boring, empathy is weaponized, cruelty is applauded, and truth is irrelevant. It’s no wonder that friendships, marriages, professional collaborations, and political alliances alike are cracking under the pressure.

Kat Rosenfield is the author of several books, including No One Will Miss Her