The Department of Homeland Security has mistreated migrant children, their parents and the very concept of truth. That, in a nutshell, is the conclusion of the DHS inspector general, who reported this month that the agency was never prepared, and remains unable, to responsibly carry out its border policy of "zero tolerance," which resulted in separating migrant children from their parents.

Yet there is no indication that the DHS intends to change its slapdash ways, or that anyone will soon be held accountable. Last weekend, President Donald Trump even said his administration is considering renewing family separations as a means of deterring migrants and asylum-seekers.

Meanwhile, DHS Secretary Kirstjen Nielsen continues to play word games — arguing to the Senate last week that Customs and Border Protection didn't "detain" children, but rather "cared" for them.

The truth is, many of those children should never have been on their own in the first place. The forced family separations at the U.S. border earlier this year resulted directly from the Trump administration's "zero tolerance policy," which "fundamentally changed" the country's approach to immigration enforcement, the inspector general found.

The disastrous results have been well-publicized: families scattered across the country, children traumatized. But the inspector general report confirmed other troubling details: Children were detained for longer than the law allows in facilities intended for short-term stays. And some migrants crossed the border illegally only after being turned away when they sought legal asylum at a port of entry.

The inspector general found that the government gave parents inconsistent information about what was happening to their children — or in some cases no information at all. A "central database" that the administration said contained the location data on separated children and parents was a complete fabrication. The inspector general "found no evidence that such a database exists."

The zero tolerance policy was steeped in bad faith from the start. On May 15, Nielsen told the Senate, "We do not have a policy to separate children from their parents." On June 17, she reiterated the false claim in a tweet: "We do not have a policy of separating families at the border. Period."

Trump himself affirmed the policy but said it wasn't his doing. "Separating families at the Border is the fault of bad legislation passed by the Democrats," he tweeted in June. White House press secretary Sarah Huckabee Sanders, responding to the anguish expressed by former First Lady Laura Bush, said the policy originated with the administration of her husband, President George W. Bush.

Falsehood has been piled atop falsehood.

It's true that, by now, most families have been reunited and that many deported parents have decided to leave their children behind in the U.S. to pursue asylum or other claims. It's also true that not everyone who seeks to enter the U.S., legally or illegally, is benign. Border security is vital.

But 2-year-olds clinging to their mothers are not security threats.

FROM AN EDITORIAL ON BLOOMBERG OPINION