Mitchell Silber, having served as the director of intelligence for the New York Police Department, and more recently provided security advice for Jewish communities throughout Europe, recommends some measures for combating anti-Semitic violence:

[D]eterrence is crucial. Would-be assailants need to be dissuaded from carrying out attacks. In recent days, the mayor’s office has committed to deploying extra law-enforcement resources to the most endangered communities, [mainly] in Brooklyn. This is a good start, but the commitment must go further. Increased police patrols, the establishment of fixed posts, and even the use of undercover officers, dressed as observant Jews, are tactics that should be deployed and sustained for the foreseeable future. Removing these resources after only a short time has proved to be ineffective; incidents return as patrols leave.

The data also show that almost two-thirds of the attacks in New York City are committed by juveniles who are local residents. This is deeply disturbing. After suspects are arrested, family-court judges have too few options. City Hall must develop an age-appropriate, restorative-justice option for those adjudicated as juvenile offenders for their participation in what could be a hate crime.

Lastly, there is self-defense. The need for this is unfortunate—in part, it’s a failure of the American promise of freedom and toleration that a minority group must learn to provide for its own defense; but we must confront the world as it is. The Jewish community must be proactive in protecting itself.

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.