Last weeks, the world looked on with horror as the Trump administration implemented its zero-tolerance policy that separated parents from their children at the US border with Mexico. Then, many were also appalled to see the Supreme Court uphold the Trump administration’s travel ban on predominantly Muslim countries.

To many in and outside of America, who view the country as it envisions itself, as a “nation of immigrants”, it is easy to view the current moment as an aberration, responding to it, as many have done, with cries of “this isn’t America!” However, as a historian, I believe Americans must have to reckon with the simple fact that, yes, it is.

It has never been easy to “become American”. Citizenship has been a zealously guarded privilege that the country has been deeply reluctant to share throughout its history – especially with people of color. The indigenous inhabitants of North America were, for example, not granted citizenship until the passage of the Indian Citizenship Act of 1924. 

When the US constitution was being written, enslaved African-Americans were deemed “three-fifths” of a person, a status they would hold for seven decades. It would take a bloody civil war and a constitutional amendment (the 14^th) to rectify this “original sin” written into the constitution and to grant African-Americans citizenship.

Once the 14^th amendment granted citizenship to “all persons born or naturalized in the United States” in 1868, new barriers were erected to keep “undesirables” out. In 1882, the Chinese Exclusion Act was passed into law, barring the entry of people of Chinese descent for the next eight decades. 

Alarmed by a spate of violent terrorist acts and the influx of “inferior races” like Italians and Jews who practiced unfamiliar religions, the United States would go on to pass the National Origins Act in 1924, establishing quotas that essentially banned Southern and Eastern Europeans from entering the US for the next four decades.

In addition, the US has a long history of separating and/or interning families of color – citizens or not. During slavery days, owners would routinely sell enslaved members of families to different owners, thereby tearing apart the family bonds enslaved people forged in the face of massive oppression. Native children were often taken from their families and sent to government-run boarding schools where they would be punished for speaking their own languages and would often never see their parents again.

During the Second World War, citizens of Japanese descent were sent to concentration camps because they were deemed a threat to national security. Indeed, part of the Supreme Court ruling in favor of the travel ban, was the decision to repudiate the constitutionality of Japanese internment – something upheld by the Supreme Court for the past half century.

This is a painful history and – for those Americans raised on the narrative written on the Statue of Liberty that they are a nation that welcomes “the tired, the poor, the huddled masses, yearning to breathe free” – a difficult one to accept. It runs against everything many Americans believe the country represents. However, this is the reality of its history. 

How does this happen over and over again? It begins with language. Words matter and how we talk about people matters. On the Irish Outsiders tour (run by New York’s Tenement Museum, of which I am president), we tell the story of the Moores, an Irish family who immigrated to the US in the 1860s only to face a tidal wave of anti-Irish prejudice. I routinely see visitors in shock when we show cartoons of the day in which the Irish were depicted as subhuman apes. 

In our modern era, where anyone can wear a “Kiss Me, I’m Irish!” T-shirt on St Patrick’s Day, it is hard to believe that the Irish were once deemed an “inferior”, subhuman race. But, in the 19^th century they were, and consequently employers felt no qualms about routinely inserting “No Irish need apply” clauses into job ads. They weren’t really fully human anyway, so why hire them?

That is why the language being used in the debate about immigration in the US is so troubling. President Trump’s recent descriptions of immigrants as “animals” who are seeking to “infest” America is deeply alarming. 

Describing an entire group as subhuman never ends well: it gives those with power permission to do whatever they want to those folks. If someone is not fully human, then we do not owe them respect or dignity. We can just tear their families apart, like the US did to enslaved African-Americans and to Native youth in previous eras, and toss their toddlers into “tender age” camps, as has been happening at the border with Mexico of late. If someone is less than human, you can do whatever you want to them.

I am sorry to say that what is happening at US borders – while inconsistent with American ideals – is far too consistent with the realities of the country’s history. The US cannot afford to think the current furor around immigration is occurring in a vacuum, and that everyday Americans do not have a part to play. Its history attests to the fact we must not turn a blind eye to cruel, dehumanizing rhetoric towards any group of vulnerable people, no matter how it is justified or who it is against. The consequences are clear.