Collaboration with the enemy is a common and often painful part of armed conflict. It is also an issue in which I have both a professional and personal interest.

The war in Ukraine is, in many ways, a transparent conflict, with cellphone images, drone cameras and satellite imagery feeding a flow of data to social media platforms and news outlets.

But in Ukraine’s occupied territories, there are actions and decisions that many people – ordinary residents and officials alike – will want to remain hidden, not just for now but for years to come.

I am a scholar of international human rights who has studied the aftermath of mass atrocities. I have also written a novel, “The Memory Seeker,” inspired by my family’s experience with the Nazi occupation of the Netherlands in World War II.

When my father died several years ago at age 96, he left behind unanswered questions about his sympathies and activities during the war. Had he supplied the Nazis with information? Had he, for example, denounced people of age to be forced to work in German factories? This doubt has led me to explore wartime complicity and how it is dealt with.

Liberating powers

There can be no doubt that there has been collaboration in the areas Russia has occupied since invading Ukraine in February 2022.

In June 2022, Bucha was the first liberated city from which collaboration with Russians was reported. The mayor of Bucha, Anatoliy Fedoruk, claimed that some local residents provided Russians with information about local people so that the invading army “knew in advance” whom to kill and where to find them.

As the Ukrainian counteroffensive advanced after the initial Russian invasion, collaboration was also reported in other liberated cities like Kharkiv, Izium and villages in the southern front.

Now, with retaken territories long under Ukrainian control, the former occupiers, collaborators and sympathizers are the ones being hunted, rooted out and, in some cases, brought to justice.

The problem of collaboration is especially thorny in Ukraine’s Donbass region, with its long history of Russian-Ukrainian cultural and linguistic interaction.

The industrialization of the area in the 19th and 20th centuries brought in a large number of Russian-speaking workers, and the region still has a significant Russian-speaking population. Since the summer of 2022, the front has stalemated, with a little more than half the region under Russian control. Divided loyalties are especially common in these circumstances and sometimes reach the upper echelons of Ukraine’s administrative power.

What to do with collaborators

The problem of collaboration was a concern for Ukrainian authorities from the first days of Russia’s February 2022 invasion. On March 3, 2022, the Ukrainian parliament amended the country’s criminal code with two new laws criminalizing any type of cooperation with an aggressor state.

The Criminal Liability for Collaboration Law prohibits the expression of certain opinions, such as dissemination of the aggressor state’s propaganda in educational institutions, denial of Russia’s armed occupation of Ukraine and refusal to recognize Ukraine’s sovereignty over the temporarily occupied territories.

It also prohibits cooperation with an aggressor state, its occupation administrations and its armed forces or paramilitary forces.

Punishment for violations may include a ban on holding positions in government and house arrest for up to 15 years, with or without confiscation of property.

The changes to Ukraine’s criminal code reflected concern among Ukraine’s leaders that collaboration with Russia would give the invading forces both ideological and military advantages.

Yet in the near-daily speeches made since then by Ukrainian President Volodymyr Zelenskyy, I was unable to find any reference to the need to root out collaborators. The reason may be that merely drawing attention to the problem of collaboration is bad for morale, even if the number of active sympathizers in a given location is very small. It also interrupts narratives of collective heroism and national unity and implies divided loyalties.

But that doesn’t mean it hasn’t been happening.

Among the more than 7,000 criminal collaboration cases opened by Ukrainian prosecutors are clear-cut violations involving collaborators who helped Russians identify military targets and others who identified neighbors who were Ukrainian loyalists and possible partisans.

In other cases, however, matters are less clear. What is one to do, for example, with those who continued their jobs under Russian occupation and provided basic services in local government offices or in education? Or the garbage collectors who continued to work while the Russians occupied their town? These kinds of cases, too, are being prosecuted.

There are risks of overreach inherent in prosecuting people like sanitation workers and school teachers. Still, this legal approach to collaboration is consistent with the fourth Geneva Convention regarding the treatment of civilians in conditions of war. The convention calls for judgments to be “pronounced by a regularly constituted court, affording all the judicial guarantees which are recognized as indispensable by civilized peoples.”

The rush to (in)justice

Sometimes the sheer number of offenses overwhelms the capacity for a state to prosecute them.

What is to be done, for example, about those who are accused of collaboration by, say, giving directions when asked by a enemy soldier or participating in a sham election? Were they acting out of a survival instinct or did they really sympathize with the Russians? Their motives may be known only to them.

Then there is the unofficial response by liberated populations against collaborators. Liberation brings tremendous release, not only of newfound freedom but of temptations toward revenge against those who once supported the occupier.

This could be one reason why societies that experience occupation followed by liberation are prone to vengeance-seeking and lawlessness.

It may be for that reason that my father decided to keep his wartime experience cloaked in secrecy.

The Netherlands, even with its global reputation for upholding human rights and democratic values, was no exception to the rush to judgment of suspected collaborators after World War II. Officially, there were trials and executions of prominent Nazis like Anton Mussert, head of the Dutch fascists, and scores of other high-ranking party members. Thousands more served prison time.

Informal tribunals were held to punish those deemed to have been sympathetic to the Nazis, including women who had illicit relationships with occupying German soldiers – who had their hair violently sheared and were publicly humiliated.

Vigilante violence was common across post-war Europe. In Italy between 1943 and 1947, vengeful partisans began a “cleansing” of police and civil servants associated with the fascist regime and went on to execute thousands of German sympathizers.

Across Europe in the aftermath of World War II, the will to revenge, for a while at least, was expressed in the justice of the mob.

The post-occupation challenge

A similar rush to justice appears to be playing out in parts of liberated Ukraine.

Journalist Joshua Yaffa, writing from liberated Izyum for The New Yorker, found a town in which hundreds had been questioned or detained on suspicion of collaboration with occupying Russians. “Every case will be looked into,” an investigator assured him. “No one should sleep too comfortably.”

Meanwhile, Ukraine watchers like Emily Channell-Justice, director of Harvard University’s Temerty Contemporary Ukraine Program, have expressed concern that Ukrainian vigilante groups may seek extra-judicial revenge.

Families divided

As the war enters its third year, the issue of collaboration will continue to gnaw away in occupied parts of Ukraine. And the longer the Russian occupation goes on, the more those in the occupied areas will be pressured into everyday complicity.

Liberation, when and where it comes, brings with it difficult conversations both in official and family settings. As with the Netherlands at the end of Nazi occupation, the search for collaborators in Ukraine will not only be made by police and partisans; it will happen within families coming to terms with the past.

And if my family’s experience of World War II is anything to go by, stories of the occupation will be parsed for loyalties, and silence will nurture suspicion.

Ronald Niezen does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.