Historical memory is dangerous. In times of crisis, its demons emerge, ugly, toxic, and potentially lethal. We saw it in Donetsk last week. Jews emerging from synagogue during Passover found themselves the target of a despicable anti-Semitic attack – new crisis, old anti-Semitism, which this time accused the Jews of acts of collaboration as far back as 1941.

When historical memory strikes, it is particularly insidious because it draws on precedents that have resonance – and therefore ring true – for the local population, and have chilling recall for the Jews themselves. It is unlikely that many of the Jews of Donetsk were old enough to be significant actors in any events 73 years ago – even the oldest would have been teenagers – but that is not a factor when historical memory comes into play.  All Jews and their descendants stand accused. Not that we should be surprised. Jews are still being blamed for the death of Jesus of Nazareth two millennia after his death, after all.

It is the intimacy and specificity of these anti-Semitic actions that is most frightening. Imagine emerging from your synagogue to find three men in balaclavas handing out fliers specifically addressed to you as a Jewish Ukrainian living in Donetsk. The flier orders you to register with the Commission for Nationalities in the Donetsk Regional Administration Building “given that the leaders of the Jewish community of Ukraine support the Banderite junta in Kiev and are hostile to the Orthodox Donetsk Republic and its citizens.” If you fail to register, the flier states, your citizenship will be revoked, you will be forced to leave the country and your property will be confiscated.

There has been much speculation about the source of the flier. It bore the signature of Russian separatist leader Denis Pushilin, who denied any connection to the fliers, or the men who distributed them. Alternative theories suggest it could be the work of Pushilin’s opponents attempting to make Russian separatists look bad. But all such suggestions are pure speculation as no group has claimed responsibility, or is likely to.

But who did what and why is not the point. Whatever the crisis, and whatever the cause, historical memory is always at hand to manipulate the truth. The very fact that anyone would think that dragging the quiet Jewish community on Donetsk into an international political crisis is clear indication how hatreds in the past become the hatreds of the future. Few people in Donetsk will remember 1941, but myths of the Jews as a source of treachery prevail, even for those who neither know the past nor associate with the Jewish community. Their very existence represents a threat, even if no one quite knows why. As soon as the extremists in the balaclavas appear on the streets and recall the past and the untrustworthiness of the Jews, then they once again become the untrusted. No one asks about the veracity of the statements – past or present – and by not denouncing the perpetrators, the threat of the Jews becomes a present threat.

Historical memory need not be so dangerous. It can be a vehicle for good as well as evil. We often say that we learn nothing from history, but in fact that is not true. We often reflect on the past and take the good from it and reinforce the good. We also have become much better at looking at the bad and reckoning with it. We do not necessarily make the best of our efforts to create effective change, but public apology has become an accepted norm, and political institutions have become more open to recognizing their own errors and instituting new laws or policies to avoid similar mistakes.  So too in our education system we do try to listen more closely to the ways in which our own society was once trapped by racism and segregation and to learn formally about why that was wrong.

Unchecked, and unheeded, historical memory has a way of reinforcing itself. One myth begets the next in a cycle of nationalistic, sectarian, partisan or religious exclusion, in which the prevailing power – or an entity in a struggle for power – manipulates historic memory to the exclusion of another group or groups. This is more than words; it is the genesis of violence.

That is why I strongly condemn the intimidation of Ukrainian Jews. The document distributed, albeit briefly and by an anonymous few, is a clear attempt at stoking anti-Semitism and intimidating the city’s Jewish residents. The dangerous manipulation of the wider population using anti-Semitic stereotypes, references to World War II and the Holocaust are foreboding language which, if not checked now, will not stop at words.

There are 103 witnesses form the Donetsk region in the USC Shoah Foundation’s Visual History Archive. They gave their life history as a reminder that the Holocaust didn’t start with gas chambers but with intimidation, edicts and exclusion. Teaching that to the next generation of Ukrainians is an ever more urgent mission in light of what we have just witnessed.

In times of peace, historical memory is never far behind. It can come back to haunt us or we can us it well to teach lessons from the recent past to strengthen our democratic values. Rather than leaflets designed to create fear, we now have the chance to listen to the voices of the witnesses of the Holocaust and to alert the current generation in Ukraine to dangers that lurk all too close behind us.