The U.S. government has forcibly separated families before. Here are 4 other times

Un-American: A word being used to describe the separations of children from their parents at the Mexican border.

History, however, suggests this is very American.

Consider slavery, when children as young as 3 were sold away from their mothers, never to be reunited. Or Indian boarding schools that took in kids to “civilize” them.

Gyasi Ross, a Native writer and attorney in Washington state, has highlighted this point on social media.

“This ain’t just Trump’s legacy; don’t try to pass it all off on him,” Ross said on Instagram. “He’s a tiny piece of the puzzle.”

Read more: Some moms too anguished to speak, attorneys for asylum seekers say

In another post, Ross wrote: “The profound sense of loss that happened to Native people as the result of boarding schools, forced adoptions, genocide, etc. It adds to that intergenerational trauma that we inherited from our moms and dads, grandmas and grandpas.”

He likened those earlier practices, roundly decried as inhumane, to the recent separation of 2,400 children at the border.

In 2016, a researcher discovered the story of a 9-year-old girl named Ashley who was sold for about $300.

Her mother, Rose, remained a house slave at a mansion in South Carolina.

This was the 1850s, roughly a decade before Abraham Lincoln’s Emancipation Proclamation, setting slaves free.

Before mother and daughter were separated, Rose gave Ashley a cotton sack. It contained a tattered dress, three handfuls of pecans and a lock of her hair. Rose told Ashley it was filled with love — always.

Read more: A slave mother’s love in 56 carefully stitched words

In an essay about slavery in Maryland, writer Desiree Lee wrote that most slave children were sold several times throughout their childhood.

Lee recounted the story of Charles Ball, who described leaving his mother behind:

"My poor mother, when she saw me leaving her for the last time, ran after me, took me down from the horse, clasped me in her arms, and wept loudly and bitterly over me. My master seemed to pity her, and endeavored to soothe her distress by telling her that he would be a good master to me, and that I should not want anything. She then, still holding me in her arms, walked along the road beside the horse as he moved slowly, and earnestly and imploringly besought my master to buy her and the rest of her children.”

Steven Mintz, a historian at the University of Texas Austin, wrote by email that "about a million enslaved African Americans were forced to move from the Atlantic coast and border states to the cotton kingdom, and most were young."

Such trauma has led to what psychologists call “racial stress.”

Jennifer Henderson, a therapist in King County juvenile court, told KUOW in 2016 that trauma affects generations to come.

“It’s a ripple effect that’s really huge,” Henderson said.

Read more: Racial stress: What 3 Seattle therapists are seeing

Off-reservation boarding schools were, in the late 1800s, intended to strip Indian children of their culture and outfit them in a whiter, more “civilized” skin.

The federal government opened 25 of these schools in a 13-year span, between 1879 and 1902.

By 1871, Adams writes, Congress identified Indians as wards of the state.

In her book, Boarding School Seasons, Brenda J. Child recounts the heartbreaking exchanges between parents and administrators. A mother writes the school: “I understand one of my boys is very sick there. I heard it from here it was rumored around if such is the case why was I not notified.”

The students were horrifically abused, sexually and physically. Many died of malnourishment and disease, owing to wretched conditions.

Canada, which borrowed its boarding school model from the United States, has set up a Truth and Reconciliation Commission to address claims of abuse at its residential schools. The U.S. has not addressed this history, however.

Professor Mintz notes that “a somewhat more positive example was Operation Pedro Pan, the transport of 14,000 young Cubans to the United States in 1960, 1961, and 1962, following the Cuban Revolution, as parents sought to ensure a better life for their children.”

Most of these youth were between 12 and 17, and most were boys.

Read more: Children Of Cuba Remember Their Flight To America

Mintz also noted the Orphan Trains, which transported more than 200,000 children out of Eastern cities.

“From the mid-19th century, the Children's Aid Society of New York sent thousands of largely Irish Catholic children on the Orphan Trains to live on Midwestern farms. Many were forced to become Protestants and were treated like slave labor. Most never saw their parents again.”

The Children’s Aid Society’s website heralds the Orphan Trains as the precursor to the foster care system. The society calls it an “emigration plan to resettle the poor and orphaned children living in New York City with farm families in the West to deter them from a life of crime and poverty.”

The program had mixed reviews: Some of the children were terribly abused and overworked; others found families that loved them. The program folded in 1929 to make way for its successor, the foster care system.

Roughly 2,400 children were separated from their parents at the U.S.-Mexico border. Some of these children were toddlers. One mother described having her nursing baby ripped from her breast.

President Donald Trump signed an executive order to stop these separations, following immense political pressure, but it is unclear what will happen to children already separated.