“Nineteen minutes before the first 911 call alerted the authorities to a mass shooting at a Walmart in El Paso, Tex., a hate-filled, anti-immigrant manifesto appeared online.”

These were the opening lines of one of the articles published by The New York Times about the attack that targeted shoppers in a southern border town supermarket at midnight on Saturday. At the time of writing, the death toll of the attack is 20.

21-year-old Patrick Crusius drove 10 hours from a Dallas suburb to carry out an attack against Latinos, in an attempt to curb the “Hispanic invasion of Texas.” This was the inference drawn from a text that was posted on 8chan, the same forum that was used to disseminate an anti-Semitic message shortly before the massacre that took place in Poway, California in April.

Mass shootings have caused hundreds of deaths in the United States in the last 40 years, and it is true that the majority of the 100 plus killings that have occurred during this period were not motivated by racial or religious grievances, but instead by the perpetrators’ desire for notoriety.

However, there has certainly been a rise in discrimination-based killings in recent years, especially since the 9/11 terrorist attacks, when it became clear that a hate rhetoric had emerged. This rhetoric has spread all over the world and is clearly behind the massacres that have taken place on five continents.

This has given rise to a debate about freedom of expression between those who believe it should be unrestricted and those who maintain that discriminatory remarks must not be tolerated because they cause irreconcilable divisions in society and can lead to violence.

The international court has already taken a stance with regard to this matter; those on trial for the genocide carried out against the Tutsi people of Rwanda in the 1990s included not only the commanders of the Hutu miltia, such as Colonel Théoneste Bagosora, but also those who incited the massacre, such as singer Simon Bikindi and radio presenter Valérie Bemeriki.

We must not wait for the hate rhetoric to turn into violence, nor should we allow ourselves to be sidetracked by sayings such as “words don’t kill; people do.” Action must be taken in a variety of contexts in order to prevent the tendency to reject anything that is different—on the basis of race, religion, sexual orientation, etc.—from seething to the point of explosion.

Hatred has been proven contagious.

The people whose responsibility it should be to stop the spread of this sickness are those who have a public platform to stand on, those whose voice is heard by others and who even serve as an inspiration. This responsibility includes the rejection of the use of nicknames or other sorts of degrading labels.

Of the individuals responsible for discouraging hatred, the first that come to mind over any others are governors. It is no secret that U.S. President Donald Trump is responsible for dividing U.S. society—this was the rhetoric he used to reach the White House—particularly as far as negative attitudes toward immigrants are concerned.

Mexico is also a society that has been divided by politics. We must not wait for the violence already present on the streets of this country to go from being a consequence of crime to one of political or social divides.

Whoever believes that this could never happen in Mexico only needs take a look at the wealth of literature available on this subject to see things differently.