Whoosh! There goes Hillary Clinton, hurt­ling leftward after another 180-degree cartwheel on a critical issue — this time, a flip-flop on charter schools.

Charters once had no greater fan. Back in 1996, Clinton hailed them as being “freed from regulations that stifle innovation, so they can focus on getting results.”

But the two national teachers unions — the National Education Association and the American Federation of Teachers — were first to endorse her latest presidential run.

So now Clinton’s script on charters might as well be written by AFT President Randi Weingarten (an informal campaign adviser).

Asked about charters at a recent town hall, Clinton said she’d backed them for 30 years — then added that now she sees problems.

“Most charter schools,” she said, “they don’t take the hardest-to-teach kids, or, if they do, they don’t keep them.”

That claim is utterly false — and right out of the union playbook.

As we’ve said before: Charters choose students by lottery. And the city Independent Budget Office found they retain more kids than traditional schools. That’s one reason waitlists for charters are so long — 50,000 here in the city.

But paying off a political debt comes first for Hillary Clinton. Of course, that’s how she gets to most of her positions these days.