Within 100 days, an estimated 1 million people, the overwhelming majority of whom were Tutsis, lay dead. The worst kind of hatred had been unleashed. What began with dehumanizing words ended in bloodshed.

Yet the dehumanization had started long before RTLM urged its listeners to “exterminate the cockroaches.” The killings in 1994 were a culmination of decades of hate-mongering, the indoctrination that began even before independence.

In 1959, Joseph Habyarimana Gitera, a leader of the radical Hutu political party Aprosoma, openly called for the elimination of the Tutsi “vermin.” The stigmatization and dehumanization of the Tutsi had begun. When the first of the many anti-Tutsi pogroms broke out that year, Gitera was overjoyed.

Over the years, whenever a sitting government ran into political trouble, it always played the Tutsi card to rally its supporters. Anti-Tutsi incitement came to the fore in November 1992, when an official in the ruling party, Léon Mugesera, openly called for the mass killings of Tutsis and for their bodies to be dumped in a river.

By the mid-1990s, the Hutu leadership was in jeopardy. Multiple political factions had emerged, and the insurgent Rwanda Patriotic Front, an organization composed mostly of young Tutsi exiles, had entered the country. For Hutu leaders, it was time to play the Tutsi card. Extremist publications had sprung up, especially a newspaper called Kangura. (Its public face, the editor Hassan Ngeze, was later convicted by the post-genocide International Criminal Tribunal for Rwanda, along with other high-level figures associated with the publication.)

But it was the private radio station RTLM—which stands for Radio Télévision Libre de Mille Collines—that illustrates the power of hate media. Rwanda had an official radio station, but Hutu hard-liners came up with the idea of creating a private radio station to carry incendiary anti-Tutsi propaganda.

It was Joseph Goebbels who said, “That propaganda is good which leads to success, and that is bad which fails to achieve the desired result. It is not propaganda’s task to be intelligent; its task is to lead to success.” RTLM was very successful. It managed to plant a seed of discord among the moderate Hutus who were slowly drawn into the extremist fold.

At the beginning of 1994, it was evident that the country’s leadership was planning something sinister, on a much larger scale than had ever been imagined. Just a month before the genocide, RTLM’s Noël Hitimana gave the first hint over the radio:

On the day when people rise up and don’t want you Tutsi anymore, when they hate you as one and from the bottom of their hearts … I wonder how you will escape.

The government’s propaganda machinery had carried out its task meticulously. Four weeks later, all the demons descended on Rwanda. Blood was flowing on the streets. The Tutsi were hunted down without mercy; they were killed in schools, churches, hospitals, and even prisons.

Today, the leaders of powerful nations use dehumanizing language in describing certain groups of people. In mass-shooting incidents, people die because someone has deemed them subhuman on account of their race or religion.

In Rwanda, our history shows where talk of cockroaches and snakes can lead. Rwanda is recovering, but it is a wonder that the country is still intact.

This article is part of “The Speech Wars,” a project supported by the Charles Koch Foundation, the Reporters Committee for the Freedom of the Press, and the Fetzer Institute.

We want to hear what you think about this article. Submit a letter to the editor or write to letters@theatlantic.com.