Educators, not just those in thrall to teaching to “the test,” share plenty of the blame for “raising young people who are, by and large, historically illiterate,” as David McCullough called the problem. For educational malfeasance this year, look to the assignment given eighth graders in the Rialto, Calif., school district. Students were asked to consider whether the Holocaust was created for political gain or didn’t happen at all — a bit of homework the Simon Wiesenthal Center called “grotesque.”

When this blew up, the district blamed misguided interpretation of Common Core requirements for critical thinking. You can blast Common Core, the straitjacket of our educational system, for many things, but teaching outright lies is not among them.

I asked a couple of the nation’s premier time travelers, the filmmaker Ken Burns and his frequent writing partner Dayton Duncan, why so many Americans can’t even place the Civil War in the right half-century, or think we fought alongside the Germans in World War II.

Burns said it’s because many schools no longer stress “civics,” or some variation of it. Why? Students complain that it’s boring, or the standards are too demanding. Civics, said Burns, is “the operating system” for citizenry; if you know how government is constructed, it’s no longer a complicated muddle, but a beautiful design.

Duncan said that Americans tended to be “ahistorical” — that is, we choose to forget the context of our past, perhaps as a way for a fractious nation of immigrants to get along. Right after the Civil War, the South was allowed to promote the inaccurate narrative of “the Lost Cause” — all about states’ rights and Northern aggression. In fact, slavery was enshrined into the very first article of the Confederate Constitution; it was the casus belli, and the founding construct of the rebel republic. That history may hurt, but without proper understanding of it, you can’t understand contemporary American life and politics.

He also mentioned how immigrants may know more about history than fifth-generation natives. To pass a citizenship test, they are required to learn things about the glory and infamy, the power and abuses — the operating system — of this democracy. It’s not too onerous to ask the same thing of 18-year-olds across the land. You can’t fix stupid, as the comic line goes; but you don’t have to teach it.