President Donald Trump finally caved to public pressure and stopped separating children and parents at the border. After long insisting he couldn’t do anything about this, he changed the policy he denied was a policy.

Yet the next steps remain unclear and of uncertain legality. Will there be internment camps? This hazy juncture is a useful opportunity to revisit a long and shameful history, because Trump is right: He didn’t begin the practice of wrenching crying children from parents.

“My brothers and sisters were bid off first, and one by one, while my mother, paralyzed by grief, held me by the hand. Her turn came, and she was bought by Isaac Riley of Montgomery County. Then I was offered to the assembled purchasers. My mother, half distracted with the thought of parting forever from all her children, pushed through the crowd while the bidding for me was going on, to the spot where Riley was standing. She fell at his feet and clung to his knees, entreating him in tones that a mother only could command to buy her baby as well as herself. … I must have been then between 5 and 6 years old. I seem to see and hear my poor weeping mother now,” Josiah Henson, a slave in Maryland, wrote in an account of his life from 1858.

Slave owner Thomas Chaplin was quoted in “Help Me Find My People,” by Heath Andrew Williams saying in 1845: “The Negroes at home are quite disconsolate but this will soon blow over. They may see their children again in time.”

Charles Ball, whose 1837 autobiography of a life in slavery included this discussion of his separation from his mother at the age of 4: “My mother then turned to (her owner) and cried, ‘Oh, master, do not take me from my child!’ Without making any reply, he gave her two or three heavy blows on the shoulders with his raw hide, snatched me from her arms, handed me to my master, and seizing her by one arm, dragged her back. … The cries of my poor parent became more and more indistinct. … The horrors of that day sank deeply into my heart.”

Thomas R.R. Cobb, a pro-slavery legal scholar in 1858, said the black family “suffers little by separation.”

In his book, “Memoirs,” Elie Wiesel remembers the last time he saw his family: “I stared intently, trying desperately not to lose sight of my mother, my little sister with her hair of gold and sun, my grandmother, my older sisters. I see them always, for I am still looking for them, trying to embrace them one last time. … What remains of that night like no other is an irremediable sense of loss, of parting. My mother and my little sister left, and I never said goodbye. It all remains unreal.”

Anne Chandler, Tahirih Justice Center, said in Texas Monthly last week: “’I’m going to take your child to get bathed.’ That’s one we see again and again. … The child goes off, and in a half an hour, 20 minutes, the parent inquires, ‘Where is my 5-year-old?’ … And they say, “You won’t be seeing your child again.’”

Last month, White House Chief of Staff John Kelly said, “The children will be taken care of — put into foster care or whatever.”

An ACLU lawsuit filed in April carried this account from a detainee separated from his 13-year-old son in October: “All I can remember is how much my son and I were both crying as they took him away. … It has been about six months since I last saw my son.”

Corey Lewandowski, a Trump surrogate, reacted by saying “womp womp,” mocking family separations on Tuesday.

“My babies started crying when they found out we were going to be separated. It breaks my heart to remember my youngest wail: ‘Why do I have to leave? Mami, I want to stay with you!’ My youngest cried and screamed in protest. … In tears myself, I asked my boys to be brave, and I promised we would be together again soon. … I do not know where my sons are, and I am very worried about them,” said J.I.L., a Salvadoran woman, in the ACLU suit.

“We have an orchestra here, joked a Border Patrol agent as children cried.

Mr. President, you’re right you didn’t start family separation. Today’s practice is not the same as slavery or Nazism, but it fits neatly into the annals of barbarism.

I hope you will stop this cruelty. To wrench shrieking children from the arms of their parents is not just cruel or abhorrent, but truly evil.

— Nicholas Kristof is a columnist for The New York Times.