Since the recent terrorist attacks in Brussels, Belgium’s large concentration of jihadists and poorly integrated Muslim population have attracted global attention. Why, asks Jeff Jacoby, are such problems typical in Western Europe but not in the U.S.?

The United States has been far more successful at assimilating and integrating Muslim immigrants into American society and culture than has Western Europe. There are no Muslim ghettos here like those in Molenbeek [the Brussels neighborhood that produced most of the perpetrators of last week’s attacks] or the Paris suburbs, where authorities turn a blind eye to antisocial behavior and aggressive incitement by radicals preaching jihad. . . .

Muslims in the United States, like other cultural and religious minorities, have had no problem acclimating to mainstream norms. . . . For despite the rise of identity politics and the balkanizing pressures of multicultural correctness, America’s melting pot still works. Generations of Muslim immigrants have come to America to escape repression, poverty, or war in their homelands. The life they have made for themselves here has been freer, safer, more prosperous, and more embracing than the existence they left behind.

There are tensions, but not enough to keep most Muslims from fitting themselves comfortably into the American mosaic. . . . “Muslims in the United States,” [one study] found, “reject extremism by much larger margins than most Muslim publics” around the world. Americanization—E Pluribus Unum—is not only a key ingredient in the American dream. It also keeps us safe.

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.