Enumerating some commonly heard misconceptions about the 2015 nuclear agreement with Tehran, Michael Oren seeks to correct them:

[One falsehood] is that Iran could somehow be bought. In return for sanctions relief, followed by tens of billions of dollars in international contracts, the Islamic Republic, the assumption went, would abandon its commitment to extending Shiite hegemony. The notion that diplomacy alone could transform Iran into a constructive regional power—oddly promulgated by the champions of multiculturalism—shocked Israelis and Arabs.

Our dismay was swiftly vindicated as Iran harnessed the legitimacy and proceeds of the [deal] to increase its financing of terror and hasten the spread of its influence across much of the Middle East. This expansion has already triggered deadly conflicts with Iranian-backed forces in Yemen and Gaza, with far larger conflagrations looming with Hizballah in Lebanon and in Syria, where Iran facilitated the government’s massacre of hundreds of thousands of civilians and its displacement of millions more.

The . . . most pernicious myth is that the only alternative to the [deal] is war. . . . But a massive invasion and occupation was never the model for confronting Iran. . . . As Israel’s ambassador in Washington in 2012, I often heard then-Israeli Defense Minister . . . Ehud Barak assure American policy makers that the bombing of Iranian nuclear sites would last no longer than one or two days, and involve minimal risk to U.S. forces.

But if diplomacy is to succeed, it must be backed by punishing sanctions and a credible military threat.

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.