On Jan. 27, the 75th anniversary of the liberation of Auschwitz-Birkenau, I will sit with thousands of people, including approximately 200 Holocaust survivors and delegations from 37 countries, astride the infamous train tracks leading into the camp. This concentration camp and killing center was part of Nazi Germanys effort to murder every Jew in Europe, resulting in the deaths of 6 million Jews. It will be a historic day and surely the last time the world will gather in the presence of so many survivors as we pledge to never forget. My thoughts are consumed with the unimaginable horrors those survivors endured deportation, starvation, torture, forced labor and the very troubled world they now inhabit.

Humanity might have assumed that, after 1945, Auschwitz and its unthinkable crimes would have contained anti-Semitism. Yet, with anti-Semitism on the rise in the lands of the Holocaust and even America, my thoughts turned to a radio show I heard last year after one of the anti-Semitic incidents in the United States. A young woman who called into the show knew about the Holocaust and about anti-Semitism, but never connected the two. This is clearly a failure of Holocaust education to teach not only that the Holocaust happened, but also how and why, and what made it possible.

Historians largely agree that three big events at the beginning of the 20th century made the Nazi rise to power possible: World War I, the Russian Revolution, and the Great Depression. But it was also big ideas dangerous ideas such as anti-Semitism and not just big events that made the Holocaust possible.

Hatred against Jews has been around since the dawn of Christianity resulting over the centuries in forced conversions, ghettoization, expulsions, and exclusion from Europes political, economic, and social life. With modern ideas came modern forms of hating Jews, confirming Jews status as a universal and enduring scapegoat. The word anti-Semitism was popularized in 1879 by German Wilhelm Marr, who believed Jews and Germans were different races locked in eternal existential struggle and therefore assimilation a dominant idea since the Enlightenment and French Revolution was not possible.

Ironically, several years later, Theodor Herzl, himself an assimilated Jew, was also articulating from a completely different perspective his view that assimilation in Europe was ultimately not viable: without a Jewish homeland, Jews could never really be safe and free. He recognized that Europes progress over the centuries did not prevent the extensive wave of organized massacres, known as pogroms, in Russia from 1881 to 1884, or the Dreyfus Affair, in which the French military wrongly convicted an innocent Jewish officer of treason, a scandal that gripped France for 12 years beginning in 1894, or the new approach of Marr and many other activists and intellectuals. Their racial anti-Semitism demanded new strategies. Segregation, conversion, assimilation were no longer workable solutions. It was no longer a matter of belief or behavior. It was a matter of biology. Therefore, removal was required.

During this period the mid- to late 19th century a combination of racial science, eugenics, and social Darwinism was used to justify and promote ideas about ethnic nationalism, identity, and colonialism. Now there was something innate about Frenchness, Germanness, and Jewishness. It was in this environment that Julius Langbehn, a German intellectual and anti-Semite said, A Jew can no more become a German than a plum can turn into an apple.

Four decades after Marr coined the term anti-Semitism, Hitler and other Nazi thinkers skillfully fused these existing ideas racial anti-Semitism, ultra-nationalism, and eugenics into a powerful ideology and an effective political movement. And eventually, into the vision and defining policy of a modern state. A genocidal state.

Hatred against Jews has a long and versatile history, easily adapting to new circumstances. Its effectiveness is such that it doesnt even require Jews. It thrives in all kinds of religious, political, and cultural arrangements, and especially at times of rapid change. Its so pervasive that even after the Holocaust, instead of receding, two new forms emerged: Holocaust denial attempts to deny or distort the established facts of the Holocaust and anti-Zionism prejudice against the Jewish movement for self-determination and the right to a homeland in Israel.

Long before social media became a powerful tool that amplifies hatred, Auschwitz-Birkenau has stood as a unique warning about the myth of progress when it comes to human nature. But so too is the long history of anti-Semitism that preceded Auschwitz and outlived it. That is something we must never forget on historic days such as this anniversary and every day.

Sara J. Bloomfield is the director of the United States Holocaust Memorial Museum.

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Anti-Semitism preceded Auschwitz and outlived it - The Boston Globe