Homeland Security Secretary Kirstjen Nielsen in the White House on March 1. (Mandel Ngan/AFP/Getty Images)

WHAT, EXACTLY, did a 7-year-old Congolese girl do to the United States to deserve the trauma that has been visited upon her — including forcible separation from her mother — by Homeland Security Secretary Kirstjen Nielsen and her immigration agents?

There is no allegation that the little girl, known in court filings only as S.S., is a terrorist, nor is there any suggestion her mother is one. Neither was involved with smuggling, nor contraband, nor lawbreaking of any other variety. Rather, S.S.’s 39-year-old mother presented herself and her daughter to U.S. officials when they crossed the border from Mexico four months ago, explaining they had fled extreme violence in Congo, and requesting asylum.

A U.S. asylum officer interviewed Ms. L, as the mother is called in a lawsuit filed on her behalf by the American Civil Liberties Union, determined that she had a credible fear of harm if she were returned to Congo and stood a decent chance of ultimately being granted asylum. Despite that preliminary finding, officials decided that the right thing to do was to wrench S.S. from her mother, whereupon the mother “could hear her daughter in the next room frantically screaming that she wanted to remain with her mother,” the lawsuit states.

The Trump administration has said that it is considering separating parents from their children as a means of deterring other families, most of them Central American, from undertaking the perilous trip necessary to reach the United States and seek asylum. Now, without any formal announcement, that cruel practice, ruled out by previous administrations, has become increasingly common, immigrant advocacy groups say. In the nine months preceding February, government agents separated children from their parents 53 times, according to data compiled by the Lutheran Immigration and Refugee Service.

Make no mistake: Ms. L and S.S. could have been placed together in a family detention center. There has been no explanation of why the determination was made to separate them; nor is there any allegation that Ms. L. is an unfit parent. The only principle at work, if it can be called that, is the idea that future asylum seekers might be deterred if they are convinced that the United States is actually a crueler and more heartless place than their native country.

By canceling DACA, President Trump is attempting to endear himself to his shrinking base, says Washington Post columnist Jennifer Rubin. He knows the only thing that truly "energizes the dead-enders is vengeance fueled by white grievance." (Adriana Usero,Kate Woodsome/The Washington Post)

Gratuitous malice toward children is not a characteristic one generally associates with the United States, but under Ms. Nielsen’s guidance, the Department of Homeland Security seems intent on changing that. A Homeland Security spokesman would not comment on this case but said that the department does not “currently” have a policy regarding separating asylum-seeking parents and children who are detained.

Separating children from their parents while they await adjudication of asylum claims is of a piece with arresting and deporting upstanding, otherwise law-abiding unauthorized immigrants who have lived and worked for decades in the United States and are the parents of U.S.-born children. That practice, too, carried out by Homeland Security deportation agents, has become far more common under the Trump administration.

Since being torn away in early November, S.S., who is being held at a facility in Chicago, has been permitted to speak with her mother, who is in a detention center in San Diego, just half a dozen times by phone. The girl, who turned 7 in December, routinely cries on the phone, according to the ACLU lawsuit. Is this the kind of protection Americans want from their Department of Homeland Security?