The UK Labor party’s descent into anti-Israelism and outright anti-Semitism has gained significant attention in the English-language Jewish press. But parallel developments in French politics have garnered less attention, even as they take place in an atmosphere of growing anti-Jewish violence unparalleled in Great Britain. Paul Berman, in a detailed consideration of the left and the Jewish question, explains:

Jean-Luc Mélenchon . . . is the leader of the Unsubmissive France party—which, at least for the moment, has replaced the left wing of the Socialist party and the old Communist party as the main political organization of the French left. And Mélenchon’s relations with mainstream Jews have likewise resembled [those of his British counterpart, Jeremy Corbyn], with variations. . . . Mélenchon is a more sophisticated man than Corbyn, more experienced, better educated, a better orator—a more attractive figure, all in all. Nobody takes him to be a man of hidden bigotries. [Nonetheless], Unsubmissive France has ended up as anti-Zionism’s principal home on the French left. Mélenchon himself has ended up as the Boycott, Divestment, and Sanctions movement’s leading champion in France.

Anti-Zionist street protests got under way in the summer of 2014, at the time of the most recent of the full-scale Israel-versus-Hamas wars in Gaza, proclaiming solidarity with Hamas. At a demonstration in Paris—called by one of the smaller Trotskyist parties, not under Mélenchon’s leadership, but drawing on the public that is his—a street full of marchers broke into a cry of “Death to the Jews!” And “Jew: Shut up, France is not yours!” together with “Allahu Akbar!” and “Jihad! Jihad! Jihad!,” which are not normally Trotskyist slogans. Such has been the cultural degeneration in nether regions of the extreme left.

Mobs set out to attack synagogues in Paris and in the suburban town of Sarcelles [and] attacked Jewish stores. And, just as Corbyn has systematically failed to notice the nature and meaning of anti-Zionism on the British left, Mélenchon managed not to notice what was going on among a significant portion of his own social base. Instead of rebuking the rioters, he congratulated them. It was the [leading Franco-Jewish organization] CRIF that issued an angry denunciation. Mélenchon responded by inveighing against the “aggressive communities that lecture the rest of the country,” by which he meant CRIF, and not the people who were staging pogroms. . . .

[T]he political significance of these French events is hard to miss, if you stop to consider that, in the first round of the 2017 presidential election in France, Marine Le Pen [of the far-right National Front] and Jean-Luc Mélenchon attracted, between them, some 40 percent of the vote—which becomes still more striking when you recall that Corbyn’s odds of becoming prime minister someday soon are pretty good.

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.