Despite his name and ancestry, the British journalist Nick Cohen never considered himself a Jew; he was raised without religion, his mother was not Jewish, and he grew up without any sort of Jewish affinity. But after confronting the rising tide of anti-Semitism in the Labor party, he realized that his approach was wrong:

[U]nless I wanted to shame myself, I had to become a Jew. A rather odd Jew, no doubt: a militant atheist who had to phone a friend to ask what on earth mazel tov meant. But a Jew nonetheless.

As one of the finest liberal ambitions is to find the sympathy to imagine the lives of others, you should become a Jew, too. Declare that you have converted to Judaism or rediscovered your Jewish “heritage” and see the reaction. It’s not just that, if you are middle-class and fortunate, you might experience racism for the first time, which in itself would be a “learning experience” worth having. You might also learn the essential lesson that anti-Semitism is not about Jews. Like rape, it’s about power.

Whether the anti-Semitic conspiracy theory is deployed by German Nazis or Arab dictators, French anti-Dreyfusards or Saudi clerics, the argument is always the same. Democracy, an independent judiciary, equal human rights, freedom of speech and publication—all these “supposed” freedoms—are nothing but swindles that hide the machinations of the secret Jewish rulers of the world. . . .

Consider how many leftwing activists, institutions, or academics would agree with a politer version: Western governments are the main source of the ills of the world. The “Israel lobby” controls Western foreign policy. Israel itself is the “root cause” of all the terrors of the Middle East, from the Iraq war to Islamic State.

Polite racism turns the Jews, once again, into demons with the supernatural power to manipulate and destroy nations.

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.