“Animals,” “aliens” and “people with bad genes” – President Donald Trump and his supporters often use this kind of dehumanizing language to describe immigrants.

In the 2024 presidential debate between Trump and Democratic candidate Kamala Harris, Trump falsely referred to Haitian refugees in Springfield, Ohio, as “eating the pets of the people that live there.” And in his Jan. 20, 2025, inaugural address, Trump spoke of “dangerous criminals, many from prisons and mental institutions,” who have illegally entered the U.S. “from all over the world.”

Using hateful, polarizing language to gain a political advantage or make an argument against a group of people, like immigrants, is not unique to the U.S.

The use of this language is associated with populist shifts in many parts of the world.

I am a scholar of international human rights who has studied the language associated with mass atrocities. I have also written about how social media can amplify misinformation and hate speech.

Some observers and analysts who follow Trump dismiss his hateful language against immigrants as empty bluster or performance art.

The implication is that Trump will not act on his most extreme promises and follow through on what he has called “the largest domestic deportation operation in American history.”

In the first few days of the new Trump administration, U.S. Immigration and Customs Enforcement officers began raids to detain immigrants living in the U.S. illegally and increased their number of arrests and deportations of immigrants, including those without violent criminal records.

Tom Homan, the U.S. border czar, has said that the government’s mass immigration deportation plans – which he said could include raids on schools, churches and other places previously considered havens – is “all for the good of this nation.”

My hate speech research shows that, as the world has seen to its horror again and again, words that slander and strip people of their voices and humanity are often a first step toward discriminatory and violent policies. At its most extreme, speaking of people as dirty and polluting and saying they lack humanity makes it easier to kill them.

There is nothing new about the hateful political rhetoric that has become common today.

In the lead-up to and during World War II, fascist leaders in Europe targeted Jews, Roma, gay people and other groups as sources of “social pollution,” as beyond being human, while describing themselves as noble and decent, embodying a pure, uncorrupted nation.

In 1920, well before the German Nazi Party came to power in 1933, its platform declared that “Only someone of German blood, regardless of faith, can be a citizen.”

Viktor Klemperer, a literary scholar who was a close observer of Nazism, wrote in a diary published posthumously in 1995 that the Third Reich’s demonizing language against Jews and other marginalized groups helped create its culture and justify its mass killings. Nazis consequently assumed the mantle of liberators as they killed those whom they saw as corrupting the “pure race,” in accordance with ideas of “racial hygiene.”

The Nazis murdered more than 12 million people.

The Nazis’ hateful language was not limited to Europe. Fritz Kuhn, a German Nazi activist, served in the late 1930s and early 1940s as leader of the German American Bund, an organization of ethnic Germans and Nazi sympathizers living in the U.S. He addressed a Nazi rally at Madison Square Garden in New York City in 1939.

Kuhn said during his speech that American citizens with American ideals are “determined to protect ourselves, our homes, our wives and children against the slimy conspirators who would change this glorious republic into the inferno of a Bolshevik paradise.”

The U.S. government stripped Kuhn of his U.S. citizenship in 1943 and deported him to Germany in 1945 because of his pro-Nazi allegiance.

Italy offers another example of how hateful speech can lead to discriminatory or violent policies. Right-wing politicians and policies have grown more popular and powerful in the past few years in Italy.

In 2018, Matteo Salvini, then the deputy prime minister who now holds the same position, denounced the Roma people, an ethnic minority. He called for their removal through a “mass cleansing street by street, piazza by piazza, neighborhood by neighborhood.”

These were not empty words.

Salvini’s call was accompanied by mob violence, mass evictions and demolition of Roma informal camps set up in the streets. The Roma people continue to face discrimination and racial profiling.

Salvini has directed his most virulent language, however, toward the tens of thousands of migrants and asylum seekers, mostly from Africa, who attempt to reach Italy via the Mediterranean Sea.

Salvini has frequently called the arrival of migrants a “flood” or “surge”. This kind of dehumanizing language makes it easier to provoke alarm about an abstract, unwanted mass of people.

The claims behind Salvini’s alarmism, however, are not borne out by facts. Since the peak of migrant sea crossings, when a few hundred thousand migrants entered Italy from 2014 through 2017, the country’s crime rate has fallen significantly.

Salvini, perhaps more than any other populist leader in the world, has turned his hateful language and use of misinformation into action. Italian authorities under Salvini’s direction have detained ships working to help rescue migrants who are in danger at sea, preventing them from carrying out those rescues.

This obstruction violates European Union law, which ensures the legal right to help anyone found in distress at sea.

In September 2024, an Italian prosecutor requested a six-year jail term for Salvini, accusing him of kidnapping 147 migrants by preventing them from landing at a port in Italy for several weeks.

Salvini said he was defending Italian borders by keeping the migrants aboard a Spanish migrant rescue ship.

Salvini was acquitted of kidnapping and dereliction of duty charges in December 2024.

We can’t be certain at this point what Trump’s and his supporters’ hateful language against immigrants, minorities and political opponents will yield.

Judging by Italy’s example and other instances, it’s possible that laws will be broken in implementing Trump’s immigration and asylum policies.

A federal judge temporarily halted Trump’s Jan. 20 executive order that told federal agencies to not process identification documents for babies born to parents who are living in the country illegally, among other scenarios.

It’s not clear how these policies will continue to unfold. What is clear is that words of hate have been used in many times and places as a justification for illegal arrests and, in some cases, as a prelude to state-sanctioned mass violence.

This article is republished from The Conversation, a nonprofit, independent news organization bringing you facts and trustworthy analysis to help you make sense of our complex world. It was written by: Ronald Niezen, University of San Diego

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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.