There’s an old expression that the longer American kids stay in American public schools, the dumber they get.

By that we mean that as kindergartners they tend to score near the top of the heap internationally, but they slip during the middle school years, and they slip even more by the time they graduate high school.

When we consider this against the additional ground we lost during the disastrous COVID lockdowns — the ones engineered by the Democrats and the teachers union pals, never forget — the picture is not only grim; it’s infuriating. As the Wall Street Journal editorial board reported last year on the National Assessment of Educational Progress (NAEP) results, also known as the nation’s report card: “Average nine-year-old scores declined the most on record in math (seven points) and in reading since 1990 (five points). Two decades of progress [were] erased in two years.”

Why not just throw more money at the problem, you ask? Oh, we’ve tried that. As the Reason Foundation reported in 2020, “Inflation-adjusted K-12 education spending per student has increased by 280 percent since 1960.”

With that kind of profligacy, is it any wonder that Randi Weingarten and her American Federation of Teachers cronies donate around 100% of their campaign funding to the Democrats every election cycle?

But trust us: Our kids haven’t gotten 280% smarter since 1960. Indeed, now we’re learning that they’ve gotten demonstrably dumber.

A new study suggests that, for the first time in nearly 100 years, the American people’s average IQ is declining, with the greatest difference in annual IQ scores being in the 18-22 age group. And — shocker of shockers — it’s a trend that the study’s authors believe might be related to the quality of education they’re getting.

As political analyst Robert Spencer sardonically puts it:

Yes, it’s hard to believe, but after years of being told that boys who think they’re girls and girls who think they’re boys are “brave” and “courageous” instead of mentally ill, and that the Founding Fathers were all racist white supremacist slave owners who did nothing good in the world, and that figuring out one’s pronouns is much more important than learning algebra or calculus, America’s teens are registering lower IQs than they have in nearly a century. It has long been obvious but now it has been proven: the woke indoctrination that passes for education in America today is making our young people stupid.

The study, published in Intelligence, “measures IQ test results among 18- to 60-year-olds to examine the phenomenon first observed by philosopher James Flynn” — namely, that starting in 1932, average IQ scores increased roughly three to five points per decade. The “Flynn Effect,” then, says that younger generations are expected to have higher IQ scores than the previous cohort.

“Data from the sample of U.S. adults, however,” writes Campus Reform’s Shelby Kearns, “imply that there is a reverse Flynn effect. From 2006 to 2018, the age groups measured generally saw declines in the IQ test used by the study, the International Cognitive Ability Resource.”

The study’s authors theorize that “a change of quality or content of education and test-taking skills” could explain the difference that education makes in the IQ of younger versus older Americans, “perhaps due to a shift in the perceived value of certain cognitive skills.” What those “certain cognitive skills” might be is unclear, but if we had to guess, it’d be a lack of sufficient emphasis in math and the hard sciences.

Trillions of dollars have been pumped into our nation’s public schools and universities for decades, and this is what we’re getting. If ever a moment was ripe for a hostile conservative takeover of Big Education, this is it.