The Otay Mesa detention center in San Diego. (Elliot Spagat/AP)

A YEAR ago, then-Homeland Security Secretary John F. Kelly said publicly that his department might separate children from parents caught crossing the border, including those fleeing violence and seeking asylum, as a punitive means of deterring others who might follow. Officials floated the idea again in December, having presented it to Mr. Kelly’s successor, Kirstjen Nielsen. Future families should be aware that “there are consequences to illegal entry,” one official told The Post.

Now, as immigration advocates document such cases occurring nationwide — some said to involve weeping children wrenched from their mothers’ and fathers’ arms — DHS officials profess outrage at suggestions that they would do such a thing “for reasons other than to protect the child.” Claims that the department would be so heartless should be regarded “with the level of skepticism they deserve,” said Tyler Houlton, a spokesman.

So the department stands accused of doing precisely what it said it might do, but assertions that it is actually doing so should be viewed skeptically?

Homeland Security has deployed that tortured logic recently in defending its treatment of a 39-year-old mother and her 7-year-old daughter, asylum seekers who fled Congo, fearing violence. The two presented themselves in November to officials at the border in Southern California, cleared an initial screening interview in which a U.S. official determined that they stood a decent chance of being granted asylum — and, within days, were forcibly separated by immigration agents. The mother, known in court papers as Ms. L., was taken to a detention facility near San Diego; the little girl, known as S.S., who screamed when separated from her parent, was taken to a facility in Chicago.

After the American Civil Liberties Union filed suit last month to reunite the two, DHS officials declined to comment on their case, citing privacy concerns, and insisted that the department does not “currently have a policy of separating women and children.” However, Mr. Houlton said in a statement, the department might sometimes do so, “particularly to protect a child from potential smuggling and trafficking activities.”

Having thereby hinted at Ms. L.’s culpability without actually alleging it — or even, f or four months, testing her DNA or blood to settle any doubts about parentage — the government then released her Tuesday. In court filings, it made no effort to explain the basis on which it doubted that Ms. L. is the girl’s mother. Thus has DHS associated itself with insinuations of guilt without evidence, along with arbitrary detention and release, and professed concern for the welfare of children, while keeping a 7-year-old among strangers. Now the ACLU has broadened its lawsuit to include what it says are hundreds of other cases involving children taken from their asylum-seeking parents.

And what of the little girl, Ms. L.’s daughter? She remains at the facility in Chicago, from which she has been allowed just a handful of telephone conversations with her mother in four months. Ms. L., according to her lawyers, intends to pursue her asylum claim but remains desperate to be reunited with her daughter. Will Ms. Nielsen and her Homeland Security agents continue to traumatize an innocent child, or will they permit the girl to be where she belongs: with her mother?