To state the painfully and terrifyingly obvious, the world is in a state of severe political and moral crisis — one we haven’t seen since the 1930s. The great postwar consensus, seventy years in the making, in which democracy was predominant and dictatorships had flagged, and in which cooperation replaced conflict, has been largely undone in less than two years. Democracy is under siege from demagoguery, sanity from insanity, the humane from the inhumane. How has it all been torn asunder so quickly?

Analysts provide angry whites, who are largely responsible for the recrudescence of authoritarian nationalism, with all sorts of excuses, and in the process often unwittingly act as their apologists. They point to economic distress under the pressures of globalization, to social displacement that pushes people to seek scapegoats, to cultural condescension that rouses anger, even to religious empowerment that encourages tribalism. The problem with these analyses is that all of these factors have been operating for some time without unleashing the ugly hatred that now engulfs us. Something else seems to be at work — something that permits the ugliness to blaze. There is, I think, an historical component, or, more accurately, an ahistorical one that we Jews know all too well. “Never forget,” Jews say, insisting on our collective memory. But the world is in the throes of forgetting. And Donald Trump, Victor Orban in Hungary, the Afd in Germany, Marie LePen in France, Putin in Russia, Erdogan in Turkey — the list goes on and on — are the results.

Of course, the impulse for authoritarian nationalism wasn’t extinguished with the defeat of Nazism. The human heart is a dark place, and the hatreds engendered by authoritarian nationalism lingered there. Anti-Semites weren’t suddenly transformed on VE Day. Neither were racists or nativists or homophobes. Nevertheless, the worst excesses of authoritarian nationalism had been contained in no small measure, I believe, because of the shadow that World War II and especially the Holocaust cast over us. It is not an overstatement to say that for the last seventy years nearly everyone has been shamed by history and compelled not to repeat it. So long as that evil hovered in our memories, authoritarian nationalists were more or less marginalized, at least in the Western world, and turned into moral and political pariahs. Until now, since WWII, no Western democracy has been governed by an extremist demagogue, and that is no accident. It is also, I would submit, less the result of political mechanisms than of the historical one. The collective memory of the Holocaust prevented the rise of authoritarian nationalism, no matter what incendiary factors were operating. Again: Collective memory immediately delegitimized any demagogue seeking power.

In part, that is because even the hint of proto-Nazism raised a giant red flag and prompted pushback against the specter of a new inhumanity. Though many Jews believe that the Holocaust analogy has become too blunt a political instrument, hauled out to stigmatize everything from police brutality to homophobia to recent nativism, and though many Jews believe it trivializes the Holocaust to do so, using the memory of the Holocaust has been a powerful tool in fighting potential authoritarian nationalism — perhaps the most powerful tool. That memory doesn’t permit excuses for hateful disaffected whites. It focuses on the awful results of that so-called disaffection.

But, alas, it is a reminder that has long been attenuating, and therein lies a problem. A survey released last April on Holocaust Remembrance Day, as The New York Times reported it, found that “many adults lack basic knowledge of what happened — and this lack of knowledge is more pronounced among millennials, whom the survey defined as people ages 18 to 34.” 31% of Americans thought that fewer than two million Jews died in the Holocaust. 41% (66% of millennials) couldn’t identify Auschwitz. And perhaps most frightening for our current political situation, 52% thought Hitler came to power through force rather than through the political process, as he did. Even in Germany, where the sensitivity to memory should run very deep, the co-leader of the far right AfD party, which is now in the Bundestag, recently told a youth conference, ““Hitler and the Nazis are just bird shit in more than 1,000 years of successful German history.” Meanwhile, the right-wing Polish government has legislated expunging Polish-Nazi cooperation from history.

All this matters because just as it is no accident that demagogues were kept at bay so long as the Holocaust was central to postwar Western consciousness, it is, I think, no accident those demagogues are coming to power as memory disappears, proving Santayana’s famous dictum all too true. We have seen this movie before, and it doesn’t end well.

Political brutishness is thriving because in losing our collective memory we are losing the historical analogies and also their moral underpinnings. “Never forget” led directly to “Never again.” The whole point of remembering was that the Holocaust was an unimaginable moral inversion, and we needed to be reminded endlessly, constantly, that it had occurred, that an entire society lost its moral bearings, that an entire society was complicit in the most heinous atrocities — reminded so that it could not happen again. The enormity of the Holocaust was so great, so beyond normal comprehension, that we needed to keep it front and center precisely because we understood, Jews better than anyone, that it tested belief. But we also realized, surreal or not, that if it happened once, it can happen again. Authoritarian nationalism and its awful discontents are where a world without values takes us if we forget.

For Jews, obviously, memory occupies a very special place in our lives, and, as it fades, it places a very special obligation upon us, especially upon American Jews, perhaps only upon American Jews. To be perfectly and sadly frank, Israeli Jews, for whom remembrance would seem critical, have forfeited that obligation, putting their own authoritarian nationalist in power while extolling ours. The lesson they seem to have taken from the past is that demagogues are perfectly fine if they are on our side. That is how fragile memory is and how easily it can be distorted to serve one’s own narrow ends rather than humanity’s broader ones. This inexcusable moral forfeiture leaves us American Jews as the reminders no one wants; the repositories of nightmares that so many people would like to forget; the moral watchdogs who help keep the world on course, even as so many people now scorn traditional morality and want to set the world off course. It is important — imperative — that we remember. If we don’t, who will?

But remembering isn’t enough. We have another, concomitant obligation: the obligation to sound a warning. It is considered hyperventilating, extremist hyperbole, to compare Donald Trump to Adolf Hitler. How dare one?! There is, after all, no Holocaust in America, no Brown Shirts or Gestapo, no Nuremberg Laws, no Kristallnacht, no bloodthirsty crowds howling and screaming against hated minorities. (Well, all but that last one.) But there is increasingly brute authoritarian nationalism, a diminution of democratic values, an intentional incitement of tribal hatreds, scapegoating, brinksmanship, hysteria, threats, accusations that opponents of Trump are enemies of the state, blatant racism, a slavish cult of personality that borders on a religion, an utter contempt for fact and truth, and, perhaps above all, the same sort of moral inversion, where right is wrong and wrong is right, that normalizes previously proscribed behavior and that once upon a time permitted Nazism to thrive. The arguments the president makes against minorities and immigrants are the arguments once used against Jews. The epithets he fires at them are the epithets once used against Jews. The tactics he uses are the tactics once used against Jews.

None of which is to say that Trump is a dictator — yet — though he certainly seems to have authoritarian aspirations and inclinations. (According to a 1990 interview with Trump’s ex-wife Ivana in Vanity Fair, Trump kept a volume of Hitler’s speeches on his bedside table.) It is to say, that there is no reason for us to remember the Holocaust if we aren’t going to use that memory to call out incipient authoritarian nationalist demagogues who threaten democracy and worse — much worse — and if we aren’t going to challenge and shame the accomplices and enablers who support the demagogues.

This isn’t a matter of “It Can’t Happen Here.” It is happening here and elsewhere. And it is happening because the world has amnesia.