Now that Islamic State (IS) has lost much of its territory in Iraq and Syria, Western countries—and Western Europe especially—are seeing the beginning of the return of thousands of their citizens who had gone to the Middle East to fight for the caliphate. Robin Simcox urges governments not to be forgiving to these IS alumni:

Western governments should have no trouble figuring out what to do with citizens who have hacked off the heads of aid workers, committed mass rapes, pushed gay people off buildings, or tried to erase the presence of religious minorities. Killing them on the battlefield is one option. If they are captured, legally detaining them is another. And if these fighters do make it home, their home countries should prosecute them. . . . What should not be an option is to treat the returning terrorists with ever-greater levels of tolerance. Yet that is the option a number of Europeans advocate.

Take Denmark. Its much-vaunted “Aarhus model” sees returnees from Syria essentially welcomed back without censure. Danish authorities treat returning fighters as naïve youths. They may be offered public housing and counseling to help them readjust to life back in Denmark. . . .

It would be a grave mistake to forget that IS and its supporters have brought bloodshed around the world, subjugating Iraqis and Syrians and slaughtering innocents in New York, Paris, Berlin, Stockholm, and countless other cities. . . . The convergence of foreign fighters that occurred in Syria was highly destructive—and nothing new. That phenomenon is fast becoming the norm. To varying degrees, it also occurred in Bosnia, Afghanistan, Iraq, and Somalia. European governments did not prosecute such travelers, so it will doubtless happen again—unless Western governments crack down on citizens who have joined terrorist groups.

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.