Shabbetai Tsvi was one of Jewish history’s most notorious false messiahs. After the Ottoman sultan ordered him forcibly converted to Islam in 1666, a number of his followers, who came to be known as the Dönmeh, converted along with him, but clung to their heterodox Jewish faith in secret. Most of them lived either in Salonica or in what is now western Turkey; some have maintained their identity until today. William Armstrong reviews a recent book about their history:

[T]he Dönmeh became one of the most conspiracy-theory-prone subjects in modern Turkey. Some have painted the Dönmeh as a secret branch of world Jewry that undermined the Ottoman regime and played a central role in the demise of the empire in order to replace it with a secular Turkish republic. Some have even claimed that Mustafa Kemal Ataturk, hailing from the Dönme heartland of Salonica, was himself a crypto-Jew.

The Burden of Silence, by the historian Cengiz Şişman, is a detailed study of the Dönmeh from the 17th century to today. Other volumes have focused on the historical and sociological development of the Dönmeh, but while Şişman does not ignore these aspects, he focuses on the theological and sectarian side of the subject.

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.