American Jews of my generation got one of history’s longest respites from antisemitism.

Hitler’s extermination of six million Jews shamed the world’s leaders and publics. Country-club antisemitism and admission quotas at the Ivies persisted; but this was a far cry from pogroms.

The catastrophe of the Holocaust also protected Israel. If you took a close look at Israel’s founding, as respected Israeli writers like Benny Morris (in his book 1948, published in 2009) and Ari Shavit (in My Promised Land, published in 2013) did two generations later, you noticed that about 700,000 Palestinians were brutally evicted.

But in 1948, most of the enlightened world gave Israel a moral free pass, earned by the extermination of the six million and the failure of the West to admit more than token numbers of Jewish refugees from Hitler. At the time, Israel was a heroic nation, not just of Jewish pioneers, but of social democratic labor Zionism.

So antisemitism went into one of its intermittent slumbers. Several factors caused antisemitism to revive, and in new, virulent forms.

Donald Trump valorized violence, dog-whistle threats of violence, and demonization of the Other. And while Trump has not (yet) explicitly attacked "the Jews," when thuggery is celebrated, antisemitism is not far behind.

At Charlottesville, Trump gave a pass to people who were chanting, "Jews will not replace us." He has taken to using the term "vermin" to describe his enemies—one of Hitler’s favorite words to describe Jews. And while Trump has a Jewish son-in-law, Trump’s former lawyers and accountants, nearly all Jews, are turning against him to save their own skins. These people are expendable.

Sharing dishonors with Trump is Bibi Netanyahu, who has managed to turn world public opinion against Israel. By cynically equating criticism of Israel’s policies with denial of Israel’s right to exist and thus with antisemitism, Netanyahu is among the all-time perverse self-fulfilling prophets.

All this creates a horrible blowback to the United States, where diaspora Jews, resented by many Israelis for being armchair critics of Israel’s excruciating security dilemma, had the temerity to feel safe. Haaretz, Israel’s left-of-center daily, recently ran an op-ed grotesquely titled "The Jews Who Join the Jew-Baiters," conflating criticism of Israel’s behavior with support for exterminating Israel and disloyalty to the tribe. Et tu, Haaretz?

By reducing complex issues to tribal loyalties, such rhetoric not only energizes antisemitism but destroys a capacity for which Jews have long been famous, as ancient as the biblical sages and as modern as a discussion over any Seder dinner table: complex ethical disputation. This is another annihilation of what’s precious in Judaism.

I am writing this from the Brandeis campus, where today’s peaceful demonstration is a protest against the arrests at Friday’s demonstration, which in turn was a protest against the ban of a pro-Palestinian group. Today’s vigil, mercifully, did not take sides. But as argument becomes uglier, more personalized and more menacing, the mantle of leadership passes to nihilists who don’t mind intimidating Jewish kids who came to Brandeis (along with those from dozens of other ethnic groups) to study and to feel safe. When Israel is murdering babies in Gaza, goes the militant thinking, why should Jews be allowed to feel safe anywhere?

I recently wrote, in the spirit of Justice Brandeis, that there should be a clear line between speech and illegal threats of violence: tolerate the former, prosecute the latter. But when explicit threats appear anonymously on Instagram, it’s not so easy. Universities are supposed to be oases for inquiry and dialogue. That whole premise is obliterated when everything becomes binary and tribal.

Netanyahu is treating Palestinian civilians as collateral damage. Two other pieces of collateral damage are reasoned dialogue and the resurgence of antisemitism, which once loosed is very hard to contain.