Most Americans are shocked by the increasingly frequent scenes of wailing mothers and babies being torn apart by government officers at the Mexican border. The Trump administration has ratcheted up the separation of children from parents as a way to deter migrants from Central America.

Some critics denounce this practice as “un-American.” It is certainly immoral and violates human rights. But it’s not unprecedented. Indeed, for long stretches of American history, it was commonplace for children to be snatched from their families.

Solomon Northup, a free black man living in New York, was kidnapped into slavery in 1841. In his memoir, “Twelve Years a Slave,” he described a slave auction where a woman named Eliza and her little daughter, Emily, were sold to different buyers. “Never have I seen such an exhibition of intense, unmeasured and unbounded grief,” he wrote.

Emily’s parting words were forever seared on Eliza’s mind: “Don’t leave me, Mama! Don’t leave me!” Another child of Eliza’s was sold at an earlier auction, and the wound of knowing that she would not see her children again would never heal. “In the cotton field, in the cabin, always and everywhere,” Northup observed, “she was talking of them — often to them, as if they were actually present.”