The Trump administration’s policy to separate parents and children at the border has been met with a mix of outrage and confusion. The government announced the cruel practice on May 7, in a departure from past policies in which families were kept together and only detained for a limited time.

The Trump administration decided to work around the time restriction imposed by courts by no longer treating families as units: Parents are detained, and children are “put into foster care or wherever,” in the infamously blasé words of White House Chief of Staff John Kelly.

As with much of the administration’s actions, it’s difficult to parse how much of this policy is a new moral low for the country and how much of it builds on historical precedent. As is generally the case, the answer is both.

The US government has never held families — nonwhite families, anyway — to be sacrosanct. In the late 19th century, for instance, at a moment of particular anxiety about American national identity, the government intervened to separate immigrant and American-Indian children from their parents to mold them into a particular kind of citizen.

The difference, though, is that such policies have almost always been rooted in misguided ideas of social uplift and national good. The new moral rot added by the Trump administration is that its policy is entirely punitive.

A long, ugly tradition

Forced separation of families was, of course, central to the American regime of slavery. In a system that allowed for hereditary enslavement, children were transformed into property at birth.

As the system of human trafficking grew over the early 19th century, children were regularly sold away from their families for both economic and punitive reasons. Supporters of slavery dismissed moral arguments against this separation, asserting that black people lacked the emotional capacity to truly feel the pain of losing a child or parent.

“Their griefs are transient,” Thomas Jefferson wrote of the enslaved black people who lived and worked with him. “Those numberless afflictions, which render it doubtful whether Heaven has given life to us in mercy or in wrath, are less felt, and sooner forgotten with them.”

There was no pretense that the separation of slaves was for their benefit. In other cases, though, politicians and reformers excused family separation as part of a broader “civilizing” project. Take the case of American Indians. In the last third of the 19th century, as the US laid claim to the full stretch of the continent, new anxieties emerged about the character of the American people, hemmed in on one side by the closed frontier and on the other by mass immigration from Europe.

In the midst of these growing anxieties, the federal government began to shift its relationship to American Indians; only an aggressive program of forced assimilation to American norms and educational practices could make this problematic population truly “American.”

In an attempt to break up tribal culture and unity, the Dawes Act of 1887 forced American Indians to abandon communal property for individual family-based farms. At the same time, tens of thousands of Indian children were taken from their families and put into government-funded boarding schools, where they were forced to change their names, learn English, dress in Western-style clothing, and (often) convert to Christianity — all in the name of a civilizing mission, which Richard Henry Pratt, head of the first boarding school, summarized in this way: “Kill the Indian in him, and save the man.”

Even as these schools became a subject of criticism and concern in the 20th century, the policy of separation remained. Between the 1950s and 1970s, as many as 25 to 35 percent of American Indian children were taken from their families, with up to 90 percent placed with white households. The decision to place these children with white families is particularly revealing because the norm for adoptions at the time was to place children with families of the same racial or ethnic background, a practice called “matching.”

But for American Indian adoptions, children were more likely to be placed outside of Native communities — which, for reasons of poverty and cultural differences, social workers often saw as inappropriate environments for raising children — an extension of the effort to scrub away Native American culture.

Programs to combat child cruelty in the 19th century intervened aggressively in the lives of immigrant families

American Indians weren’t the only ones subject to new forms of government intervention in the family. As mass immigration stirred fears that “American” stock — read: pure white bloodlines — would be diluted, reformers sought ways to intervene in immigrant families. In an era when children were being reimagined as innocents shaped by their environment, reformers believed that the only way to ensure immigrant children would grow up to become good citizens was through strong state intervention.

It’s not a coincidence that at the same time the Bureau of Indian Affairs was investing in boarding schools, states began to create child cruelty organizations that were vested with police powers that allowed them to remove children from their homes. That may sound like an unmitigated good — and, in many cases, children were removed from genuinely harmful environments.

But such organizations, like the New York Society for the Prevention of Cruelty to Children, mostly run by white Protestant men, regularly confused poverty and cultural differences with abuse. Children could be removed if their parents engaged in acts as mundane as cooking with garlic or drinking wine at dinner.

It was part of a new wave of interventions in family life, both benign (mandatory public education) and less so.

Many of these reformers were acting out of cultural and racial chauvinism, an assumption that they knew what was in the best interest of the families they were tearing apart. The Trump administration is making no such claims. Their vision of America is not assimiliationist (an idea with its own problems) but exclusionary: making America too cruel for immigrants, including refugees and asylum seekers, to risk crossing the border.

But perhaps that cruelty will sharpen for us, in ways that earlier eras obscured, what a tremendous injustice it is to force families apart, and to more fully grapple with our country’s history of doing so in the name of making American great.

Nicole Hemmer, a Vox columnist, is the author of Messengers of the Right: Conservative Media and the Transformation of American Politics. She is an assistant professor at the University of Virginia’s Miller Center and co-host of the Past Present podcast.

The Big Idea is Vox’s home for smart discussion of the most important issues and ideas in politics, science, and culture — typically by outside contributors. If you have an idea for a piece, pitch us at thebigidea@vox.com.