Adam Armoush is, for the moment, the most famous Jewish victim in the world — and he’s not even Jewish. He’s a 21-year-old Israeli Arab who was visiting Berlin with his friends and decided to test their suspicions that it was unsafe to don a kippa (skullcap) in public. Strolling down the street in the Prenzlauer Berg, a gentrified neighborhood, Armoush was attacked and beaten with a belt by a Syrian refugee who shouted, “Yahudi!”

Anti-Semitic attacks have become increasingly common in Germany and throughout Europe. The roster of homicides in France, for example, includes the 2015 murders of four shoppers in a Paris kosher supermarket; the 2012 murders of seven, including three children, at a school in Toulouse; and the stabbing and burning of an 85-year-old Holocaust survivor last month, to cite just a few. Jews also suffer nearly daily threats and contempt from their neighbors.

A 2013 survey by the European Union’s Fundamental Rights Agency asked Jews whether in the past year they had personally witnessed anyone being physically attacked because he or she was Jewish. Among the French, 9.7 percent said yes. Among Swedes, 6.7 percent said they had. In 2016, majorities of Jews in a number of European countries, including Germany, France, and Sweden, said that they sometimes or always avoided displaying clothing or other items that identified them as Jewish, and large numbers say they’ve considered emigrating.

The response among European leaders has varied. Some avoid the question or retreat to platitudes. Jeremy Corbin, leader of Britain’s Labour Party, is quite comfortable with left-wing anti-Semitism, which tends to bleed easily into every other kind. He defended the artist who painted a mural showing hook-nosed capitalists playing Monopoly on the backs of naked workers. He also calls Hezbollah and Hamas “friends.” France’s Emmanuel Macron has been much better. In January, when an 8-year-old Jewish boy was attacked in Sarcelles, Emmanuel Macron called it an “attack on our whole country.”

How can it be that only 70 years after the Holocaust, Europe’s Jews do not feel safe? It’s ironic, but one reason is guilt. Eager to live down their histories of colonialism and racism, Europe has welcomed millions of immigrants from the Third World. . For the Jews, tormented more than any other group in Europe’s history, this expiation comes at their expense. Many of the Muslim immigrants arrive with anti-Semitic animus. A recent survey in the United Kingdom found that 55 percent of Muslims harbored anti-Semitic attitudes, compared with 12 percent of the overall population.

In France, victims reported that 53 percent of their attackers were “people with extremist Muslim views,” 18 percent were “people with extremist left-wing views,” 4 percent were “people with extremist right-wing views,” and 3 percent were “people with extremist Christian views.”

The influx of immigrants has helped to spark the resurgence of right-wing nationalism in Europe, which is also chilling for the Jews. Hungary is led by an increasingly open fascist, Viktor Orban, and the Sweden Democrats (who are the opposite of their name) received 14 percent of the seats in the latest parliament.

Seventy-three years after the fall of the Third Reich and 27 years after the implosion of the Soviet Union, the western world is forgetting what can happen when the center does not hold. The Jews are now, as they have always been, a bellwether.