In 1424, at a time when such banishments were common, the German city of Cologne expelled its Jewish population, which had been there since at least the 4th century CE. Looking back on her research into the city’s Jews, which formed the basis of her first book, the historian Shulamit Magnus explains the anomalous history that followed:

Cologne, unlike most places, rigidly excluded Jews [after the expulsion, rather than] letting some back in only to re-expel and readmit, as happened in many Central European locales. In Cologne, there was no ghetto, no Jewish street—no Jews at all. In the rare event that political pressures forced permission for a (very wealthy) Jew to traverse the city en route elsewhere, he (I don’t recall reading any were women) had to be accompanied in the streets by a red-cloaked guard, proclaiming, “Jew! Jew!”

Then, in 1789, the French Revolution took place, and shortly thereafter was carried across the map of Europe by armies of the Revolution. Cologne, on the left bank of the Rhine, near France, was not just conquered, but annexed. . . . It is well known that the French Revolution emancipated French Jews and that Revolutionary armies then razed ghettos and imposed emancipation wherever they went. . . . It is less well known that Napoleon [who seized power from the Revolutionary government] was profoundly Judeophobic and that, as emperor, he severely compromised the emancipation the Revolution had extended and instituted discriminatory legislation that harked back to that of the ancien régime.

Under Napoleonic legislation, Jews were guilty until proved innocent. For Jews to engage in business, they first had to obtain a special “Jew-license” in addition to any regular license needed to conduct business. To qualify for this license, Jews had to prove that they had not engaged in usury or fraud and to bring a character testimonial from the local synagogue, implicating the organized community in systematic discrimination. . . . Napoleon’s anti-Jewish legislation remained on the books on the left bank of the Rhine until 1847.

Two extraordinary events demonstrate something important about Israel’s most fervent adversaries. One was a speech given at something called The People’s Forum (funded generously by Goldman Sachs), which stated, “When the state of Israel is finally destroyed and erased from history, that will be the single most important blow we can give to destroying capitalism and imperialism.”

The suggestion that this tiny state is the linchpin of a global, centuries-old phenomenon like capitalism goes well beyond anything resembling rational criticism. Even if Israel were guilty of genocide, apartheid, and oppression—which of course it is not—it would not follow that its destruction would help end capitalism or imperialism.

The other was an anti-Israel protest that took place in front of New York City’s Memorial Sloan Kettering Cancer Center, deemed “complicit” in Israel’s evils. At organizers’ urging, participants shouted their slogans at kids in the cancer ward, who were watching from the windows. Given Hamas’s indifference toward the lives of Gazan children, such callousness toward non-Palestinian children from Hamas’s Western allies shouldn’t be surprising. The protest—like the abovementioned speech—deliberately conveyed the message that Israel is the ultimate evil and its destruction the ultimate good, cancer patients be damned.

The fact that Israel’s adversaries are almost comically perverse does not mean that they can be dismissed. If its allies fail to understand the obsessive and irrational hatred that it faces, they cannot effectively help it defend itself.