Born in the German city of Mannheim in 1654, Johann Andreas Eisenmenger spent nearly two decades studying the Talmud and other rabbinic texts with members of the Jewish community of Amsterdam, to whom he presented himself as a prospective convert. Then, in 1700, he published one of the best researched, and most influential, works of anti-Jewish slander. Henry Abramson writes:

Spanning 2,000 pages over two brick-like volumes, Entdecktes Judenthum (“Judaism Unmasked”) is an exhaustive survey of every possible passage from the Talmud that could be distorted to reflect badly on Jews and Judaism. Its verbose subtitle thoroughly describes his intent, which was to prove how “the stubborn Jews frightfully blaspheme and dishonor the Holy Trinity . . . . and despise and curse to the uttermost extreme the whole of Christianity.” He also promised “ridiculous and amusing stories” to boot, “written for the honest information of all Christians.”

Eisenmenger’s purpose and even his methodology were hardly new. Jew-haters have been mining the Talmud for talking points since the 13th century, when the apostate Nicholas Donin first denounced it before Pope Innocent III. Few, however, were able to penetrate the depths of this massive, ancient text written in a mixture of highly coded Aramaic and Hebrew.

Eisenmenger began his lifelong deception in 1680 at the age of twenty-four. By the time he was ready to bring his malicious book to print, he could count many rabbis among his teachers, including the prolific David ben Aryeh Leyb of Lida [in modern-day Belarus]— then chief Ashkenazi rabbi of Amsterdam.

For the past three centuries, from John Peter Stehelin’s [1748 English-language abridgment] to the ugliest parts of the Internet, anti-Semites have relied on Eisenmenger’s [perverse] research to promote hatred. Eisenmenger strove for accuracy in citation and translation, but criminally distorted the meaning of the passages in context with unacceptably tendentious commentary to promote awful lies like the infamous blood libel.

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.