Established in 1516, Venice’s walled-off Jewish quarter would give its name to, and provide a model for, scores of similar zones in cities throughout Italy and Germany that decided Jews simply couldn’t be allowed to live among Christians. The 500th anniversary of its founding has occasioned celebrations and commemorations in the city, including an elaborate exhibit that will be on display in the summer and fall. David Laskin writes:

When the ghetto was at its height in the 17th century, 5,000 Jews from Italy, Germany, France, Spain, and the Ottoman empire carved out tiny, distinct fiefs, each maintaining its own synagogue, all of them crammed into an acre-and-a-quarter of alleys and courtyards. Confinement was a burden, but it also provided an opportunity for cultural exchange unparalleled in the Diaspora. . . .

Jewish merchants and bankers were vital to the flow of commodities [through the city during its commercial golden age], but as Venice declined, the Jewish presence dwindled. By the outbreak of World War II, Jewish Venice had shrunk to 1,200 residents. Today, with the city’s total population hovering around 58,000 (down from 150,000 before the war), there are about 450 Venetian Jews left, only a handful of them residing in the [former] ghetto.

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.