BEFORE THE spring of 2018, U.S. Customs and Border Protection had no system in place to track migrant children who were separated from their families. That was the case even though, it now turns out, the Trump administration, in its first months in office, had already begun wrenching scores of babies, toddlers, tweens and adolescents from their parents to deter illegal border crossings. Then, beginning in April last year, the administration doubled down, systematically breaking apart migrant families upon apprehension at the border — still with no means of tracking and reuniting the families it had sundered.

Only now, 16 months after a federal judge ordered migrant families reunified, has the scale of the administration’s cruelty become understood. Most Americans thought the policy detestable. It was far worse than they imagined.
Having resisted demands that it compile a definitive listing of the families broken apart by its policies, the administration finally relented this spring when U.S. District Judge Dana M. Sabraw ordered a full accounting. Last week, hours before the deadline set by the judge, the government submitted the numbers to the American Civil Liberties Union, to whose volunteers it has fallen to clean up the mess created by President Trump, former attorney general Jeff Sessions, former homeland security secretary Kirstjen Nielsen and others.
No, it was not only the 2,814 traumatized children who had been separated and were in custody under the government’s policy of “zero tolerance” for unauthorized border crossers when Judge Sabraw ordered families reunified in June last year. It turns out that an additional 1,556 children had been separated in the preceding 12-month period, beginning in July 2017. Of those, more than 300 were 5 years old or younger.
Imagine, if you can, the suffering visited upon those children, including many still in diapers and requiring afternoon naps, by the administration’s cavalier brutality and incompetence — the anguish of little girls and boys removed from their parents for weeks or months because of a president lacking a conscience and a government whose data systems were not suited to the task of reunification. Those wounds won’t heal easily, or ever.
Incredibly, having shattered so many families, the administration threw up its hands and declared the task of reuniting them beyond its capabilities. Even now, volunteers working under the coordination of the ACLU are going door to door in Guatemala and Honduras, seeking to ascertain whether families have recovered their children. 
More than 1,000 additional migrant children have been separated in the past 17 months on the grounds, the government says, that their parents or guardians endangered or abused them, or were unable to care for them, or were criminals, or were not actually their parents. The ACLU maintains that in some cases, those separations are also unjustified, triggered by minor offenses committed by the parents, such as shoplifting or driving without a valid license. It has asked Judge Sabraw to set a narrow standard for separations.
In all, the administration has taken at least 5,460 children from their parents. That is a stain on Mr. Trump, on the government he leads and on America.