When the great Italian conductor was dissatisfied with an orchestra’s performance, Terry Teachout writes, “he flew into screaming rages whose verbal violence would likely not be believed were it not for the fact that there were secret tapes made.” As far as his private life was concerned, he was “a compulsive philanderer whose love letters to his mistresses are explicit to the point of pornography.” Yet, as a new biography shows, he displayed a great deal of moral integrity when he was wooed by murderous regimes:

[T]here is . . . a parallel between the passionate conscientiousness of [Toscanini’s] music-making and his refusal to compromise with Hitler and Mussolini, both of whom were sufficiently knowledgeable about music to understand what a coup it would have been to co-opt the world’s greatest conductor. . . .

If anything, Toscanini’s hatred for the Nazis was even more potent [than for Italian fascists], above all because he was disgusted by their anti-Semitism. A philo-Semite who referred to the Jews as “this marvelous people persecuted by the modern Nero,” he wrote a letter to one of his mistresses in the immediate wake of the [1938] Anschluss [of Austria] that makes for arresting reading eight decades later, “My heart is torn in bits and pieces. When you think about this tragic destruction of the Jewish population of Austria, it makes your blood turn cold.” . . .

Toscanini felt so strongly about the rising tide of anti-Semitism that he agreed in 1936 to conduct the inaugural concerts of the Palestine Symphony (later the Israel Philharmonic) as a gesture of solidarity with the Jews. In an even more consequential gesture, he had already terminated his relationship with the Bayreuth [music] festival, where he had conducted in 1930 and 1931—the first non-German conductor to do so. While the founder of the festival, Richard Wagner, ranked alongside Beethoven, Brahms, and Verdi at the top of Toscanini’s pantheon of musical gods, he was well aware that many of the members of the Wagner family who ran Bayreuth were close friends of Adolf Hitler, and he decided to stop conducting in Germany—Bayreuth included—when the Nazis came to power. . . .

Toscanini never performed in Germany again, nor would he forgive those musicians . . . who continued to do so.

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.