In the clearest possible thumbs-down on the entire American educational establishment, homeschooling is booming.

The Washington Post last week estimated that it’s risen from 1.5 million children in 2019 to up to 2.7 million now.

Since 2018, it’s up 103% in New York, 108% in Washington, DC, 78% in California — all areas with laws hostile to homeschooling.

Public-school enrollment has crashed by millions more, since most parents simply pulled their kids to private and parochial schools — or, where possible, to public charter schools.

Across the board, it’s a reaction to what parents learned during COVID.

They saw that remote learning (despite the heroic efforts of a few truly dedicated educators) was a total farce, with all too many schools not even trying to truly teach.

And that teachers unions — with the backing of local school districts, especially in big cities — put the adults’ interests’ first, all across the board, keeping schools closed even long after the vaccines rolled out with teachers given priority access.

Heck, we now know American Federation of Teachers chief Randi Weingarten used her influence with the Biden White House to slow the nation’s return to in-classroom instruction.

Other factors play a role, but union fingerprints are all over those, too: The AFT and National Education Association are all-in on the dubious Diversity, Equity and Inclusion mandates forcing (progressive) racist nonsense into education, and on the extremist LBGT+ agenda, too.

In much of the country, parents simply wanting to opt out of that madness see no choice except homeschooling.

So its appeal spans every divide of politics, geography and demographics.

Indeed, the unions (shamefully) went along with the rollback of school discipline that’s led to rising violence, especially in urban schools.

The NEA/AFT response is to push their media allies to churn out “news” about the perils of homeschooling, and to finger right-wing extremists as driving the broader push for parental control.

But shouting “vast right-wing conspiracy” doesn’t cut it.

Students across America lost years of academic ground, as measured by National Assessment of Educational Progress testing.

Parents across the spectrum know that politicians, school leaders and teacher unions failed their kids.

That trust is hard to regain — and Randi & Co. aren’t even trying.

So expect homeschooling, and every other alternative to union-run education, to keep on booming until America’s parents have real reason to believe the public schools are actually being run in the children’s interests again.