In 1520s, a man named David Ha-Reuveni traveled through Europe purporting to be the son of a Jewish king in a distant land who ruled over three of the ten lost tribes of Israel. Reuveni was received in European courts, and his grandiose plans sparked messianic fervor among Jews, as well as the conversos of Iberia and their children—children like Solomon Molcho, who became Reuveni’s most devoted follower. Joel Davidi Weisberger writes:

[Reuveni] first made his appearance in Venice in 1523, claiming to be the commander-in-chief of his father’s army, and requested aid from the local Jewish community. Although most regarded him with suspicion and even derision, he did gain a measure of support among notable members of the community who helped him gain an audience with the Pope Clement VII at Rome. His proposition was nothing short of astonishing: an alliance between the forces under his command and those of Western Christendom—in other words, a joint Jewish-Christian Crusade to liberate the Holy Land from Islamic rule.

[In] 1525 Reuveni was in Portugal where King John III received him as an official ambassador. Reuveni’s appearance in the city spread like wildfire and fired the imagination of Jews and Christians alike. Particularly smitten by him were the so-called marranos, those Jews who had been forced to live outwardly as Christians but secretly held on to their Jewish heritage. One of them, Diogo Pires, met Reuveni and asked to be circumcised. Reuveni, probably fearing for the success of his mission, dissuaded the young man.

But Pires circumcised himself and took on the Hebrew name Solomon Molcho. Reuveni, aghast at the young man’s audacity, urged him to flee the country, which he did. Most scholars agree that he studied Kabbalah for a time in Salonika, [then part of the Ottoman empire], under the tutelage of Rabbi Joseph Taitazak. There . . . Molcho gathered a group of devotees and it was there that he published his first book of sermons.

Molcho later returned to Christian Europe and, in 1532, was burned at the stake in Mantua. While the rabbinic scholar Yosef Shlomo Delmedigo of Crete and the German Jewish communal leader Josel of Rosheim remembered Molcho as a dangerous crank, the greatest halakhist and mystic of their day, Rabbi Joseph Caro—who may have met Molcho in Salonika—viewed him as an inspiration and a model of righteous martyrdom,

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.