We know – or think we know – why so many home-grown goons stormed the U.S. Capitol. Most notably, a defeated cult leader pumped his Kool-Aid down their throats.

But that’s not the whole story.

The Former Guy was able to gin them up because they were so dumbed down. They had no idea they were doing anything wrong. They felt justified to breach the legislative branch simply because the president had decreed it. They had no clue about separation of powers, or co-equal branches of government, because they’d never learned about either. They truly believed that the vice president could magically overturn the election (one facet of The Big Lie) because they’d never learned how our democracy actually works.

For this, we can blame the demise of civics education in America.

In 1838, a young Abraham Lincoln warned in a speech that unless children are taught “reverence for the Constitution and its laws,” we might fall prey to “mobocratic” rule. What we suffered on Jan. 6 was a mobocrat invasion – perhaps a harbinger of the future.

In a new report released today, a group called Educating for American Democracy tells the tale: “Civics and history education has eroded in the U.S. over the past fifty years, and opportunities to learn these subjects are inequitably distributed. Dangerously low proportions of the public understand and trust our democratic institutions. Majorities are functionally illiterate on our constitutional principles and forms. The relative neglect of civic education in the past ­half-century – a period of wrenching change – is one important cause of our civic and political dysfunction.”

Granted, it’s tough to prove that the Capitol mobocrats brutalized cops and smeared their feces simply because they lacked civics instruction. Suffice it to say that a demagogue’s odds of success are heightened when the people he seeks to exploit have little understanding of how the system works – and likely don’t know what they don’t know.

I wish we could poll all the insurrectionists, because I bet we’d discover that a disproportionate share would flunk a civic literacy exam. Last year, the Woodrow Wilson National Fellowship Foundation reported that only one-third of native-born Americans (and only 19 percent of those under age 45) would be able to pass the basic test that’s given to immigrants who aspire to become citizens.

Some stats for our Hall of Shame: 57 percent of native-born Americans don’t know how many justices serve on the U.S. Supreme Court; 60 percent don’t know what countries the U.,S. fought in World War II (um…the fascist ones?); only 13 percent know when the U.S. Constitution was ratified; only 24 percent could name one thing that Ben Franklin was famous for (37 percent said he invented the light bulb).

In another recent survey, this one conducted by the American Council of Trustees and Alumni, less than 40 percent of respondents knew how long members of Congress served; more than half didn’t know that the Bill of Rights was the name given to the Constitution’s amendments. And a 2016 survey conducted by the Annenberg Public Policy Center found that only 26 percent of Americans could name all three branches of government. (The new Republican senator from Alabama, ex-football coach Tommy Tuberville, can’t name all three branches, either.)

When I was a public school kid – at the risk of sounding old – we had civics classes all year long (commonly called Social Studies), and I distinctly remember (to cite one random example) that we couldn’t advance to fifth grade unless we correctly named all nine members of the high court. But today, 31 states reportedly require only a half-year of civics education, and another 10 states require nothing.

In public education during the last half century, civics has taken a back seat to science, technology, engineering, and math. Nothing wrong with the STEM curricula; we need people on the cutting edge of those disciplines. But two educators, making the pitch for civics, recently warned: “Without a basic understanding of our constitutional system, the foundations of democracy and the separation of powers enshrined in it, how can Americans discern fact from fiction? Without understanding what generations have fought and died for – those core principles of putting country before leader or party, the checks on power our Founders insisted on – how can they be informed and empowered citizens that our system requires to survive?”

Chief Justice John Roberts agrees: “(Our constitutional) principles leave no place for mob violence…We have come to take democracy for granted, and civic education has fallen by the wayside. In our age, when social media can instantly spread rumor and false information on a grand scale, the public’s need to understand our government, and the protections it provides, is ever more vital.”

He wrote that 13 months before the Capitol was stormed.

If we continue to ignore these warnings about our education system, too many Americans will remain putty in the paws of demagogues. As the current cult leader exclaimed on the stump five years ago, “I love the poorly educated!”