Despite official inquiries, public scandals, and the formal censure of several party activists, anti-Semitism is very much alive and well in the British Labor party; indeed, at its most recent conference, a motion was proposed to question the historicity of the Holocaust. The novelist Howard Jacobson comments on the feeble efforts of Jeremy Corbyn, the party’s leader, to deny anti-Semitism’s presence while insisting that it has nothing to do with “anti-Zionism.”

By way of a sop to critics, a rule warning against such conduct as might be deemed detrimental to the party—such as hostility to disability, gender reassignment, civil partnership, pregnancy and maternity, oh, and anti-Semitism—was adopted. But condemnation of Zionism was as febrile as ever and any Jew—particularly any Israeli Jew—willing to join in could count on a standing ovation. No man is a prophet in his own land, but an anti-Zionist Israeli is a hero in this one. . . .

To this, Jeremy Corbyn and those closest to him are tetchily indifferent. Mr. Corbyn goes out of his way not to use the word “anti-Semitism,” and when he is forced into condemnation of it he invokes the platitude that Labor opposes all racism and discrimination. The “all” is important. Burying anti-Semitism among offenses such as bullying and sexual harassment is a dodge to equalize things that are not equal and in the process ensure that anti-Semitism is rarely privileged with a mention of its own.

There is method in this evasiveness. To implicitly deny the existence of anti-Semitism—as some continue to deny the Holocaust—is to render it as a sick fantasy of the Jews’ own making, a pathology whose function is to blunt the edge of the anti-Zionist critique. That Jews invoke anti-Semitism primarily to silence critics of Israel is a tired canard, but it continues to be pressed into service. It serves a purpose: it libels the Jews as liars in the act of protesting innocence of any such offense. And if anti-Semitism is a chimera, then anti-Zionism, so often conflated with it, has nothing after all to apologize for. . . .

What needs to be insisted on is that Zionism—the idea not the political events to which it has given rise—is integral to the Jewish mind and imagination. Those who say they are against Zionism but not Jews are speaking in riddles. It is not the Jew who needs to see himself apart from anti-Zionism; it is the anti-Zionist who needs to ask himself what feeds his fervor.

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.