Mardini’s and Binder’s case, though garnering more media attention than average, is one of many such cases in the past few years. Similar charges have been brought against volunteers working with migrants all over the European Union, in what has come to be known as the “criminalization of solidarity”—the repurposing of laws originally intended to target human traffickers in order to prosecute those who aid migrants and refugees.

Strikingly, even as migrant arrivals to Europe have dramatically decreased, instances of criminal prosecution of humanitarian workers are on a steady rise. In 2018 alone, at least 89 people were placed under investigation or prosecuted for their involvement with border crossers, according to the UK Institute of Race Relations; 20 were prosecuted the year before. These cases have occurred on the EU’s periphery and at its center, in countries with vastly different political climates and experience of migration. Some, like Binder and Mardini, have been prosecuted for things they deny ever doing; others, like French farmer Cédric Herrou, who helped dozens of migrants over the French-Italian border, are taken to court for acts that they acknowledge carrying out but see as moral imperatives. “It is enraging to see children, at 2 in the morning, completely dehydrated,” Herrou told the court at his trial, referring to children he’d seen by the side of the road.

In 2000, the United Nations adopted a convention on trafficking that defined the act as transporting border-crossers for personal financial gain. But a EU council directive two years later was less specific, instead broadly criminalizing “the facilitation of unauthorized entry, transit and residence of migrants.” The 2002 directive mandated prosecution of for-profit migrant transporters, but left it up to the discretion of the member state to go after the not-for-profit variety—“cases where the aim of the behaviour is to provide humanitarian assistance.” In practice, it seems to have paved the way for member states to ignore precisely this distinction.

Despite isolated cases before 2015, it wasn’t until the refugee crisis hit Europe that the prosecution of humanitarian aid to migrants based on the 2002 directive truly coalesced into a discernible phenomenon. Over one million migrants arrived on EU shores in 2015, moving freely from Greece north to Germany. By 2016, that number was down to under 400,000, and it has continued to fall every year since: the deliberate result of EU policies that sent asylum seekers back to Turkey, disbursed millions of dollars to African governments who committed to stopping migrants long before they set foot on EU soil, and closed internal borders throughout Europe.