The Conventional Wisdom About War Crimes is Wrong

Could anyone, once thrust into a war zone, kill innocents and commit atrocities?

For decades, experts have debated why combatants—including seemingly normal people who once worked standard jobs and love their family back home—are capable of war crimes. The question is one of profound importance; scholars estimate that 80 million to 200 million people have been victims of mass killings since the beginning of the 20th century. In Ukraine, the Office of the United Nations High Commissioner for Human Rights has recorded at least 15,246 civilian casualties since Russia invaded in February, though the true figure is likely much higher. At least 390 children have been killed. In some areas, like Bucha, there is strong evidence that Russian troops tortured, raped, and mutilated civilians.

According to a new book by Jonathan Leader Maynard, an expert on mass killings at King’s College London, ordinary people in any society can commit atrocities if they fall under the sway of certain beliefs about the wars they are fighting. They are not unusually evil. “They’re within the normal ambit of human psychology,” Leader Maynard told me, “and they’re guided by a relatively normal set of human motivations.”

This means that to prevent more mass atrocities in Ukraine and elsewhere, we need to properly understand how ideology motivates people to perform extreme acts of violence.

Leader Maynard points to three theories commonly used to explain mass killings and war atrocities. But all three can be debunked.

The first explanation is what I call the Broken Brains hypothesis. This is the notion that the sadism of torturing innocents or committing genocide makes sense only if the perpetrators have abnormal brains, or even are psychopaths. Experts turned to the Broken Brains theory when trying to understand the Nazis. An array of psychiatrists closely examined and interviewed the Nuremberg war criminals. After one of the top Nazi perpetrators, Robert Ley, hanged himself while awaiting trial, his brain was preserved, shipped by air mail to the United States, and studied by neuropathologists, who found that he had brain damage, “a longstanding degenerative process of the frontal lobes.”

But as research continued, it became clear that Ley was an outlier, that the architects of the Holocaust likely did not have brain pathologies, and that the Nazis’ genocidal machine had so many people pulling various levers that most of them had to be neurologically normal. This was not a case of a few psychopaths, but rather of millions engaged in what Hannah Arendt famously called “the banality of evil.”