(Editor’s note: This article is published as part of our ongoing coverage of International Holocaust Remembrance Day. Read related content here.)

As for many, last month’s Holocaust Memorial Day has a personal relevance for me. Though I have never religiously identified as “Jewish,” had I grown up in interwar Germany rather than late 20th century Britain I would have been classified as a Mischling (of the first degree) under the 1935 Nuremberg Laws – a person of half “Aryan” and half “Jewish” ancestry. Following the January 1942 Wannsee Conference, I would have been targeted and likely killed by the German state. I was not, because my Jewish ancestors had fled to Britain – not from persecution by the Nazis, but from pogrom-ridden Tsarist Russia and Romania in the late 19th Century

Such escape was not an option in the 1930s and 1940s for almost six million Jews, a comparable number of non-Jewish citizens of the Soviet Union, as many as three million Poles, around half a million Roma and Sinti, half a million Serbs, and almost 300,000 disabled persons, plus thousands of victims of other groups and nationalities murdered by Nazi agencies or collaborators in Nazi-controlled Europe.

The earlier Tsarist pogroms should remind us, however, of the wider relevance of Holocaust Memorial Day. However singular the Holocaust was in its scale and its intended scope, it was an ultimate instance of a broader phenomenon – the intentional mass killing of innocent, unarmed people – that predated the Nazis’ particular brand of genocidal extremism, and that remains a fundamental threat to millions of people worldwide today. Researchers on genocide and violent conflict, like myself, have debated this contemporary dimension of the Holocaust’s relevance ever since. At the end of World War II, the philosopher Hannah Arendt wrote that “the problem of evil will be the fundamental question of postwar intellectual life in Europe.” 

But what form, precisely, does Arendt’s “problem of evil” take in contemporary politics? What does the Holocaust teach us about the broader danger of mass violence in human relations, and how does it continue to inform out understanding of atrocities committed around the world?

In his justly celebrated Black Earth: The Holocaust as History and Warning, historian Timothy Snyder starts where most people start: with the figure of Adolf Hitler and his apocalyptic worldview of racial struggle. There is a good reason to start here. History students are regularly taught to be sceptical of “great men theories of history,” in which everything happens because certain political leaders decide that they should happen. Yet Hitler’s centrality to the Nazi movement, and his resulting dominance over German politics between 1933 and 1945, was exceptional in a modern political context. In a very real sense, Nazism was Hitlerism (and was often referred to as such in the 1930s). The Holocaust fundamentally depended on an utterly delusional set of conspiratorial and pseudoscientific claims about Jews and other “threats” to the “Aryan race” formulated or rearticulated by Hitler.

Yet while Hitler and his worldview lie the heart of the path to the Holocaust, he is not what really mystifies us about it. Hitler was a racist and a self-aggrandising fantasist. The origins of these traits may be interesting, but such people exist in every society – some of them become terrorists today. The mystery is not so much how Hitler could exist or believe what he did, but how his extremist brand of politics could capture Germany society as a whole.

Early scholarship on Nazi Germany offered two main answers to this question: one focused on the regime’s totalitarianism, the other focused on the long history of antisemitism. For scholars such as Hannah Arendt, Franz Neumann, Isaiah Berlin, and William Shirer, the Nazis’ mass mobilization of German society rested on the combination of a sophisticated totalitarian apparatus of control through violent terror, and an ideology of racial supremacy (and collective subordination to the leader) that capitalised on deep antisemitic tendencies within European culture. The balance between the two varied across scholars. In his monumental study of Nazi government, Behemoth, Franz Neumann stressed coercive control, writing that while “democratic ideology is successful if it can persuade or attract” the “National Socialist ideology persuades through its use of terror.” Other scholars put more emphasis on underlying sympathy for antisemitic ideology – an argument that took its fullest form in the work of a later scholar, Daniel Goldhagen, in his controversial Hitler’s Willing Executioners. For Goldhagen, the Holocaust was fundamentally explained by the simple fact that the majority of Germans “were animated by antisemitism, by a particular type of antisemitism that led them to conclude that the Jews ought to die.”

But these kinds of explanation have fallen out of favour with historians. The claim that the vast bulk of ordinary Germans were committed to exterminatory antisemitism is hard to square with the relative popularity of liberal, left-leaning parties (and the anti-Fascist communists) in the decades preceding the rise of the Nazis. It is not clear that Germans, moreover, were exceptional in their hostility towards Jews prior to the Nazi takeover of power. “Anti-Semitism may have been strong in influential pockets, especially in comparison to the west,” writes the leading Holocaust historian Christopher Browning, “but it was not so pervasive or strident as in territories to the east, from which beleaguered east European Jews looked to Germany as a land of holden opportunity.” 

Detailed research on the actual rank-and-file killers in the Holocaust, moreover, paints a complex picture, in which some were enthusiastic killers, but many were more apathetic or participated due to a messy mix of overlapping motives (as is typical in most forms of political violence). The Nazis were clearly able to gain immense popular support from large swathes of the German population who were culpably untroubled by the party’s antisemitism – but fervent belief in that antisemitism was often not the primary reason. Moreover, focusing on deep support for antisemitism leaves the Nazi’s extensive violence against groups other than Jews, or the significant participation in the Holocaust of many non-Germans and non-Nazis, unexplained. Nor are historians these days so ready to endorse an image of Nazi government as an all-pervasive apparatus of terror. At its 1930s peak, the entire Gestapo secret police comprised just 20,000 officials (many of whom were bureaucrats rather than actual secret policemen) in a society of 68 million – not nearly enough to coercively micromanage society by terror. As historian Richard Overy emphasises of both Nazi Germany and Stalin’s Soviet Union: “For the vast majority who were not the direct victims of repression, daily life was…more normal than the popular image of either dictatorship suggests.”

Partly in response to these problems, many scholars began to theorize the Nazis’ ability to perpetrate the Holocaust as rooted in more commonplace features of modern societies, in which masses of ordinary people can be bureaucratically organised in service of state projects. The influential “Milgram experiments,” in which most people were found willing to inflict seemingly severe electric shocks on screaming human beings when ordered to do so by a scientist in a position of authority, and Philip Zimbardo’s “Stanford Prison Experiment,” in which individuals readily became abusive “guards” in a simulated prison environment, suggested that human beings would often harm each other simply because they felt that such behaviour was expected of them by peers or superiors. Hannah Arendt’s views shifted in response to the trial of Adolf Eichmann, one of the principal organizers of the Holocaust, in 1961. Rather than a totalitarian true believer, Arendt saw in Eichmann a ‘banal’ bureaucrat, capable of entirely suspending his moral imagination as he dutifully followed orders to organise the genocidal destruction of millions. 

Yet this picture of the Holocaust has also come under fire. If many earlier explanations exaggerated the ideological enthusiasm of the Holocaust’s perpetrators, this latter camp of theorists seemed to understate it. Eichmann, many historians have pointed out, was not a thoughtless bureaucrat (a front that it suited Eichmann to present at his trial) but a determined agent of the Nazi state who wilfully advanced genocidal policies. A disproportionate number of Holocaust perpetrators also seem to have been strong supporters of the Nazis, and those who were not often did not blindly obey orders from authorities, but either exercised initiative in participating violence or, conversely, found ways to subvert and oppose elements of the violence. 

Modern scholarship thus tends to synthesise elements of these two pictures of the Holocaust – and it is that synthesis that helps us understand the wider universe of cases of genocide and atrocities, and the dangers of extremism in our own societies. Critical to this view is an awareness that history’s worst atrocities do not emerge out of some single, unified foundation. “The people” in the societies where such atrocities occur – be this Nazi Germany in the 1940s, Mao’s China in the 1960s, the Former Yugoslavia in the early 1990s, or civil war Syria today – are not simply enthusiastic extremists, fearful victims cowed into submission by terror, or apathetic automatons. “The people” in every society are diverse, even when extremist politics takes over: some are fervent supporters, others are tacit sympathisers, many are largely apathetic, while large numbers are disgruntled opponents. Most hold somewhat ambiguous attitudes. As Overy observes of both Hitler’s Nazi regime and Joseph Stalin’s Soviet Union: “dissent, enthusiasm and compliance rubbed shoulders in Soviet and German society. They could inhabit the same individual as he faced the different things that society asked him to do, or as social and political obligations changed through time.” 

This view carries two key implications for the way we think about the dangers of extremist atrocities today. First, potential foundations for mass extremism exist in most societies. They are not a unique property of early 20th century Germany, nor of specifically antisemitic or blatantly racist populations. This is partly because our societies are not as thoroughly progressive, tolerant and liberal as we like to pretend – large numbers of people show sympathy for authoritarian, divisive, prejudicial, and callous attitudes. Indeed, we should not forget the times when our own governments have proved able to kill civilians in large numbers – in their hundreds and thousands in the Korean War and Vietnam War – with no meaningful military benefits, yet with enthusiastic support from large swathes of the people. 

More importantly, societies simply do not need to be overwhelmingly supportive of harsh, authoritarian attitudes for extreme violence to occur. Extreme movements – such as the Nazis – spend much of their time espousing, not their most hateful ambitions, but the seemingly reasonable grievances and frustrations of ordinary citizens. Once in power, they do not publicly defend self-avowedly diabolic plans, but cloak their policies of violence in the guise of legality and necessity, a narrative in which all the violence is simply an unavoidable security measure, a course forced on them by their opponents, a righteous action to punish the real villains. Rather than relying on wildly alien and manifestly “evil” arguments, in other words, extremists capitalise on precisely those conventional justifications for violence and state coercion with which we are all too familiar. They also, unsurprisingly, do not subject most of their supporters to their most abusive actions. This is why so many ordinary Germans, in the title of Milton Mayer’s study of life in Nazi Germany, “thought they were free.”

Second, the foundations for extremism usually are held in check by various restraints. Societies are not liberal, moderate, progressive and free because almost all their citizens – let alone their politicians – are liberal, moderate, progressive or committed to the freedoms of others. But societies consistently avoid extremism when the infrastructures of freedom are strong: when key institutions and norms encourage a more decent, rights-respective, lawful politics; when powerful social movements and independent media hold leaders to account, expose rather than reinforce political fantasies, and champion the rights of the vulnerable; and when information is produced and scrutinised by scholars, civil servants, and non-governmental organizations devoid of either government repression or vested interests. The strength of these infrastructures varies. There is good reason to think that contemporary democracies are more robustly free than, for example, Weimar Germany in the 1920s. Yet no infrastructure is rigidly immovable, and once key components are eroded and weakened, once sections of the political and cultural elite attempt to mobilise the foundations of extremism, the system of restraints can swiftly collapse. 

That, of course, is not the end of the story. Sometimes the international community, supporting movements within a state who oppose extremism, can mobilise to oppose atrocities – as in East Timor in 1999. This is key reason to continue to sustain international efforts to affirm states’ responsibility to protect civilians at home and abroad. Even when genocides and mass killings do occur, forces of opposition do not disappear, and in every great atrocity can be found individual stories of rescuers and resisters who oppose the violence, such as the inhabitants of the French village of Le Chambon-sur-Lignon, who saved around 1,000 Jews from Nazi persecution in Vichy France. All efforts to strengthen our capacity to recognise and resist extremism carry potential to prevent or limit the violence in our world.

While genocide on the scale of the Holocaust is historically exceptional, its central lesson is that the broader danger of extreme atrocities is not. In the words of the great historian Ian Kershaw, the Holocaust “lit a warning beacon that still burns brightly: it showed how a modern, advanced, cultured society can so rapidly sink into barbarity… It showed what we are capable of.” Only by rejecting false narratives of conflict and polarization, and maintaining systems of rights and freedoms for all, can we hope to prevent that capability from once more becoming a reality.

IMAGE: Burning candles on a black table (Getty)