Antisemitism rose under Trump. Then it got worse.

The Anti-Defamation League last week released a report showing that, in 2021, there were more antisemitic incidents in America than in any year since the group started keeping track over 40 years ago. “We’ve never seen data like this before, ever,” Jonathan Greenblatt, national director of the ADL, told me.

The rapid growth of Jew hatred isn’t limited to the United States. According to a new report from the Center for the Study of Contemporary European Jewry at Tel Aviv University, antisemitic incidents were up last year in countries including Australia, Britain, Canada, France and Germany. Comparisons to 2020 might be misleading, because pandemic lockdowns likely reduced the numbers of antisemitic assaults and in-person harassment. But in several countries, including the United States, there were more antisemitic incidents in 2021 than in the pre-pandemic year 2019.

As the Tel Aviv University report pointed out, there are countless conferences, training programs and legislative proposals devoted to fighting antisemitism. “There is no shortage of organizations dedicated to the cause, which gained the commitment of world leaders,” it said. “The data presented in this report suggest that, despite all these efforts, something has gone terribly wrong.”

Something has obviously gone wrong. The question is, what?

Conservatives might be tempted to blame strident anti-Zionism, and that’s part of the story. Both the ADL and researchers in Tel Aviv use a definition of antisemitism that can conflate it with anti-Zionism, concepts I think should be kept separate. It’s clearly antisemitic, however, when Israel’s enemies blame all Jews for the country’s treatment of the Palestinians. According to the ADL report, of 2,717 antisemitic incidents in the United States last year, 345 involved references to Israel and Zionism. The examples detailed in the report aren’t ambiguous; they include Palestinian supporters pushing a man in a yarmulke into a glass window and yelling, “Die, Zionist!”

It’s a mistake to associate all of these 345 incidents with the left; 68 were “propaganda efforts by white supremacist groups to foment anti-Israel and antisemitic beliefs.” More broadly, right-wing extremism was behind 484 of all antisemitic incidents in the U.S. last year, 18% of the total.

The radicalization of the Republican Party has helped white nationalism flourish. Antisemitism started increasing in

2015, when Donald Trump came on the political scene and electrified the far right, then spiked during his administration.

Mr. Trump is now gone, but the Republican Party has grown more hospitable than ever to cranks and zealots. Two Republican members of Congress, Marjorie Taylor Greene and Paul Gosar, spoke at a white nationalist conference this year.

The antisemitism of the QAnon conspiracy theory — always latent in its fantasies of elite blood-drinking cabals — has also become much more open. As the ADL has reported, one of the most popular QAnon influencers, GhostEzra, “is an open Nazi who praises Hitler, admires the Third Reich, and decries the supposedly treacherous nature of Jews.”

But for a huge number of antisemitic episodes, the political motive, if there is one, is illegible. Much of the threat to Jews in America seems to come less from a distinct, particular ideology than from the broader cultural breakdown that’s leading to an increase in all manner of anti-social behavior, including shootings, airplane altercations, reckless driving and fights in school.

In 1899, Émile Durkheim, a French Jew and one of the fathers of modern sociology, wrote a short essay called “Antisemitism and Social Crisis.” It was an attempt to grapple with the explosion of antisemitism accompanying the conviction of Alfred Dreyfus, a French artillery officer falsely accused of treason. Durkheim described how Jews were blamed for defeats in the Franco-Prussian War of 1870, and how a burst of antisemitism in 1848 followed an economic crisis the previous year. Similarly, he wrote, “our current antisemitism is the consequence and the superficial symptom of a state of social malaise.”

For Durkheim, wrote sociologist Chad Alan Goldberg, “malaise” meant not just widespread unhappiness but social dissolution. “Durkheim understood France’s social malaise in terms of a pathological dearth of moral and social regulation, a condition that he termed ‘anomie,’ ” Mr. Goldberg wrote.

Anomie was a chronic condition of industrial society, which eroded traditional social bonds. But, according to Durkheim, when society was rent by “painful crisis” or “abrupt transitions,” anomie could become acute. At those moments, people turned on Jews, the classic scapegoats.

Our society, clearly, is not healthy. It was unwell before the pandemic and is in much worse shape now. The pandemic and the accompanying changes in the way people live, work and go to school were wrenching and destabilizing. Isolated people turned to social media, which, as the Tel Aviv University report pointed out, abounded with conspiracy theories blaming Jews for spreading the coronavirus so they could profit from vaccines.