All too often, the issue of anti-Semitism in Europe is written about as an amorphous problem, like it was some noxious vapor floating in the ether that occasionally inflicts itself on individual Jews. In reality, it usually manifests in three distinct forms—left, right, and Muslim. Earlier this month, the European Union Agency for Fundamental Rights launched its second survey on anti-Semitism. Interviewing some 16,500 individuals across 12 member states, it touts itself as “the biggest survey of Jewish people ever conducted worldwide.” The findings are dispiriting yet confirm what many know but few will say: that European anti-Semitism is predominantly Muslim in origin, followed in close second by the left-wing variety. According to “respondents who experienced some form of anti-Semitic harassment in the past five years,” 30 percent of the perpetrators were Muslim, 21 percent were people espousing a left-wing view, and only 13 percent expressed a right-wing view.The survey’s most arresting discovery is that a third of respondents have considered emigrating from Europe because they no longer feel safe there as Jews. A similar number say that they “at least occasionally avoid visiting Jewish events” out of fear for their personal safety. This problem is particularly acute in France, home to Europe’s largest Jewish (and Muslim) population, where a slow-motion exodus has been underway since the deadly 2012 Islamist attack against a Jewish school in Toulouse took the lives of seven people, including a rabbi and his two children, aged 6 and 3. Subsequently, a pair of brutal murders (of Holocaust survivor Mireille Knoll and 67-year-old Sarah Halimi) shocked the world, and less severe anti-Semitic attacks on Jews are a near-daily occurrence in major French cities. Emigration is also increasingly on the minds of Jews in Britain, where 40 percent say they would “seriously consider” leaving the country if Jeremy Corbyn, the anti-Semitic leader of the Labour Party, were to become prime minister.Unsurprisingly given the leadership profile of the country’s official opposition, left-wingers are responsible for a full quarter of anti-Semitic harassment in the United Kingdom, more than twice that of right-wingers and exceeded only by those whose views or religious background the victims could not describe. In Germany, where the absorption of over 1 million mostly Muslim migrants has propelled the nationalist Alternative für Deutschland into becoming the country’s third-largest political party, sparking fears of a right-wing revival in the historic home of national socialism, 41 percent of the perpetrators of anti-Semitic harassment are reported to be Muslim and just 20 percent right wing.“For many years, being Jewish in Denmark was not a problem,” a middle-aged Danish woman told the pollsters. “In this millennium, we have started to see threats, offending statements and [a] terrorist attack against persons characterized as Jews. The majority of these have been initiated by people of a Muslim background.” A man in his late 30s, also from Denmark, relates that, “One of the fundamentally biggest problems for Jews in Denmark is that we do not dare visibly show our Jewish identity in public, at school, at the gym, etc. for fear of anti-Semitic statements, unfortunately, in particular from our Muslim neighbors.” Being Jewish in Europe today sounds a lot like being gay not so long ago: a mandatorily closeted existence.And yet for all their valid concerns about Muslim anti-Semitism, European Jews are not cottoning to the anti-Muslim bromides on offer from Viktor Orbán, Marine Le Pen, Geert Wilders and other right-wing nationalists who cast themselves as genuine friends of the Jewish people. Mindful that bigotry against one minority invariably leads to bigotry against others, 72 percent of European Jews “express concern about increasing intolerance toward Muslims,” that is, they sympathize with the plight of the religious group from which the plurality of anti-Semitism, and all of the murderous anti-Semitism, originates.Before solving a problem, it is necessary to identify it. Few political leaders or journalists or other public figures are willing to state the obvious fact that the main source of anti-Semitism in Europe today is not among the usual suspects on the far right but the red-green alliance, where the primeval Jew hatred of Muslim immigrants is excused away by the anti-Zionist cosmopolitanism of the secular left. No one should have required a survey to see this, but now we have the data.