George Santayana, the Spanish- American philosopher, famously said “those who cannot remember the past are condemned to repeat it.” Regrettably, it seems that Europe has failed to learn from its darkest days of anti-Semitism in the last century and is now condemned to repeat those same mistakes once again.On Monday, April 8, Jews around the world will pause to mark Israel’s official Holocaust Martyrs’ and Heroes’ Remembrance Day, remembering the 6,000,000 Jews – and many others – who perished on the death fields of Europe during the Holocaust.Yet around many parts of Europe today, anti-Semitism has once again reared its ugly head, surging to levels unprecedented since then.In France for example, it is becoming near impossible to keep track of the almost daily occurrence of anti-Semitic attacks. In 2012, there was a 58 percent increase in anti-Semitic incidents, with an even more alarming 82% rise in physical and verbal assaults committed in public.This comes barely a year after the March 2012 Toulouse shooting, in which an Islamic terrorist killed three Jewish children and a rabbi. And then only in February this year, a woman was arrested outside the very same Toulouse school after attempting to stab a student.Hungary has also seen a rapid rise in anti-Semitism in the last year, in parallel with the rise of the neo-Nazi Jobbik party, now the third-largest political party in Hungary. In the past 12 months, leading Jewish figures have been physically assaulted on the streets of Budapest, Israeli flags burnt outside the main Budapest Synagogue and Jewish graves have also been desecrated.In late 2012, Marton Gyöngyösi, a leading Hungarian politician from the Jobbik Party outrageously called for the creation of a “registry” of Jewish MPs and government officials in Hungary on the basis that they presented a “national security threat.”In Greece, which has also seen the rise of neo-Nazism, the far-right Golden Dawn Party has openly questioned the need for the country to mark International Holocaust Remembrance Day, calling it “unacceptable.” The party has also denounced Israel’s “Judaic atrocities” and spoken about “Zionist world control.”In other parts of Europe, Belgium has seen a 30% increase in the number of anti-Semitic complaints filed in 2012, while 2012 marked the third-worst year on record for anti-Semitic incidents in the United Kingdom.Meanwhile, last month a shocking video was aired in the Netherlands, in which Dutch teens were quoted as saying they “regret” that Hitler didn’t finish “the job he began.” In the video, one of the interviewees said on camera: “I am more than pleased with what Hitler did to the Jews,” while another added: “I hate Jews, period. Nothing you do will make me change my mind.”From Poland to Russia, to Romania, Czech Republic, Sweden, Ukraine and even Germany, Jewish cemeteries and memorials – many holding the bodies of Holocaust survivors – are also being vandalized and desecrated.In short, 68 years after the end of the Holocaust, virtually no part of Europe is free of the evil of anti-Semitism and hatred that led to Europe’s darkest period.The difference however, is that today’s anti-Semitism is being directed not only against local Jewish communities and individuals, but also in the public vilification and delegitimization of the State of Israel. This is being waged by a dangerous union of radical Islam, the far Left and the neo-Nazi far Right.So what can be done to combat this scourge? First, we must persuade the international community that anti-Semitism is not just a “Jewish problem,” but a human problem. As the UK chief rabbi, Sir Jonathan Sacks, has said: “A civilization or a country that has no room for Jews has no room for humanity.”We must also recognize that the Holocaust did not start with the death camps and crematoriums; that’s where it culminated.It started with words and with the demonization of an entire group of people, while society just turned the other cheek. Today, that demonization is also directed against the State of Israel – the Jew among the nations.Whether it’s denying the Holocaust or Israel’s right to exist as a Jewish state, or as the Turkish PM Recep Tayyip Erdogan said in February this year, that Zionism was a “crime against humanity,” there is absolutely no room for such language and it must not be allowed to go unchecked.It is also more important than ever for our politicians and leaders to unequivocally condemn all manifestations of anti-Semitism and denounce those who seek to resort to it. While many fine leaders have done just that, they need to be even louder and faster in their condemnation.The best way to defeat anti-Semitism and the forces of evil is to show that we, as a society, stand united in the global fight against hatred, intolerance and anti-Semitism. This is the lesson that Europe must learn in order to avoid repeating mistakes of its past.The writer is the director of Research at The Israeli-Jewish Congress, a not-for-profit organization devoted to combating anti- Semitism and commemorating and honoring the victims of the Holocaust.