In 1391, a horrifying wave of pogroms swept through Spain, leaving tens of thousands of Jews dead, and many others forcibly converted to Christianity. Among the latter was Profayt Duran of Perpignan, who took the name Honoratus de Bonafide and embarked on a successful career as court astrologer to the king of Aragon. But Duran—an accomplished rabbinic scholar, polymath, and author of a commentary on Maimonides’ Guide of the Perplexed—continued to write in Hebrew under the pseudonym Efod, and produced a number of works on Jewish theology, Hebrew grammar, and biblical exegesis, as well as two anti-Christian polemics. Duran’s life and work are the subject of Maud Kozodoy’s The Secret Faith of Maestre Honoratus. Eric Lawee writes in his review:

Kozodoy rightly lays stress on Duran’s rationalism as a key not only to his intellectual personality but religious identity. . . . [She] suggests, on the evidence of his writings, that Duran’s rationalism buttressed his Jewish pride and fortified his ongoing allegiance to Judaism after his conversion. Indeed, he seems to have identified rationality with Judaism, and Kozodoy shows how this conviction informed what are by far Duran’s most daring works: two brilliant and innovative polemics in which he subjected Christianity to theological ridicule and an exacting historical critique.

Duran wrote the first of his anti-Christian books about three years after his conversion. It takes the form of an epistle addressed to one of his contemporaries who was a genuine Jewish convert to Christianity. Here the innovation lies not so much in the work’s contents but in its form, especially the “barbed biblical allusion[s]” with which Duran pointed out the folly of an educated Sephardi Jew abandoning a faith in harmony with reason to embrace one at odds with it.

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.