As revelation follows revelation of nasty comments by Labor politicians about Jews and the Jewish state, it has become increasingly evident, argues Nick Cohen, that the problem is not one of a few bad apples. Rather, he writes, anti-Semitism lies close to the very core of the party’s dominant ideology:

[The Labor parliamentarian] Naz Shah’s picture of Israel superimposed onto a map of the U.S. to show her “solution” for the Israel-Palestinian conflict was not a one-off but part of a race to the bottom. But Shah’s wider behavior as an MP—a “progressive” MP, mark you—gives you a better idea of how deep the rot has sunk. She ignored a Bradford imam who declared that the terrorist who murdered a liberal Pakistani politician was a “great hero of Islam” and concentrated her energies on expressing her “loathing” of liberal and feminist British Muslims instead.

Shah is not alone, which is why I talk of a general sickness. Liberal Muslims make many profoundly uncomfortable. Writers in the left-wing press treat them as Uncle Toms, as Shah did, because they are willing to work with the government to stop young men and women from joining Islamic State. While they are criticized, politically correct criticism rarely extends to clerics who celebrate religious assassins. As for the anti-Semitism that allows Labor MPs to fantasize about “transporting” Jews, consider how jeering and dishonest the debate around that has become. . . .

Challenging prejudices on the left wing is going to be all the more difficult because, incredibly, the British left in the second decade of the 21st century is led by men steeped in the worst traditions of the 20th. . . . When Jeremy Corbyn defended the Islamist likes of Raed Salah, who say that Jews dine on the blood of Christian children, he was continuing a tradition of Communist accommodation with anti-Semitism that goes back to Stalin’s purges of Soviet Jews in the late 1940s.

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.