In September, a Syrian chemical-weapons plant was destroyed, most likely by Israeli airplanes, not far from a high-tech Russian anti-aircraft installation. Yet Russian troops did not respond to—or attempt to prevent—this attack on their Syrian ally. Nor has Moscow acted to protect its coalition partners from numerous other Israeli airstrikes over the past few years. Likewise, Russia did not retaliate when the U.S. launched cruise missiles at a Syrian air-force base in April. Guy Plopsky concludes that, despite repeated threats, the Kremlin wishes to avoid conflict with either America or Israel:

Moscow’s warnings to Israel are . . . directed more toward the Syrian and Russian public than they are toward Jerusalem. Offering no threatening response to Israeli airstrikes would make the Kremlin appear weak, prompting pro-Assad factions to question Moscow’s commitment to the regime and weakening Russia’s influence.

At the same time, Russia has been rebuilding Syria’s air defenses in the hope that they would deter both Israel and the coalition from further strikes. Russia’s defense ministry has mentioned Syrian air defenses in warnings directed at coalition forces and has pledged to “increase [their] effectiveness.” . . .

As for Russia’s own air defenses, Moscow has not utilized them to defend Assad’s forces and is unlikely to do so for fear of an armed confrontation with the U.S. and its partners. Indeed, while Syrian fighters are known to have flown escort missions for Russian strike aircraft, the reverse has not occurred. Furthermore, like Israel, the U.S. maintains a de-confliction line with Russia and has developed agreements to avoid clashes. . . .

Contrary to Kremlin rhetoric, targeting stealth aircraft and cruise missiles remains a major challenge for Russian air defenses. Furthermore, due to the radar horizon limit, even non-stealth aircraft can significantly reduce detection by flying at very low altitudes. Also, sophisticated electronic-warfare systems can degrade the performance of enemy radar. Hence, at long ranges, [even the best Russian surface-to-air missiles] can realistically be expected to intercept only cumbersome targets successfully. . . .

This does not mean Russia’s air defenses in Syria should be neglected. On the contrary: Jerusalem and Washington must keep a close watch, particularly as the post-Islamic State stage of the Syrian conflict sets in.

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.