Lefties and their media minions painted President Joe Biden’s border opening as humane and just, but it brought the largest child-trafficking operation in history.

A quarter-million unaccompanied children, waved into the interior, simply disappeared because the Bidenites made no real provision for keeping track of them — with Xavier Becerra, now running to become California’s next governor, one of the chief culprits.

US law requires the feds to carefully supervise and track unaccompanied minors they let enter the country, passing them only to vetted sponsors, ideally family or former neighbors, who agree to take good care of the kids, enroll them in school and ensure they show up to future immigration court hearings.

But Biden’s de facto “come on in” signals led to hundreds of thousands of children, mostly from South and Central America and many orphaned or abandoned, flooding in — and his people let the system collapse.

More than two-thirds of these kids fell off the radar: Their sponsors quit answering the phone, vanished from whatever address they’d provided and of course didn’t bring the children to court.

The Biden White House shrugged off its legal duties and let the chaos continue.

Some of the kids are likely with genuine guardians who simply think it best to avoid immigration authorities.

But thousands (at least) had been sent into our country by trafficking rings who had “super sponsors” — criminals using fake IDs to claim sponsorship of multiple unrelated children — indenture them to construction, factory or slaughterhouse jobs or simply sell them to pimps.

It seems the Biden crew accepted this child slavery, often open, as just a cost of its “just” immigration policies.

Kids working in meat-processing factories was hardly the worst; America’s cities are flooded with young girls forced into prostitution, sometimes “servicing” dozens of men a day.

All because Biden took office determined to undo all the “inhumane” Trump border policies.

Democratic politicians who’d wept over “kids in cages,” namely children in holding facilities (really just dorms with educational and recreational facilities) awaiting placement with legitimate sponsors, said nothing about kids in slavery.

Acting Attorney General Todd Blanche has announced criminal indictments of some of the worst known super-sponsors, but the Justice Department has identified tens of thousands of addresses repeatedly used to sponsor children under the Biden crew’s oblivious eyes.

Specifically on the watch of Health and Human Services Secretary Xavier Becerra, whose Office of Refugee Resettlement was supposed to protect the kids.

As the Bidens tour the country selling their books, and other administration alums like Becerra seek office, a decent press corps would demand answers on this nightmare.

Joe, Jill, Xavier: What do you have to say to the tween girls forced to sell their bodies on the streets of New York, Los Angeles and other “sanctuary” cities because you chose to wink at child enslavement?