So…we now have a Rosa Parks Barbie, apparently. In a way, it seems like a triumph of the Civil Rights Movement, right? But only in a way. Like the conservative backlash against the NYT’s 1619 series, Barbie’s version of history proves once again that there is still an unyielding third rail in America’s public conversations about history.

What’s wrong with a Rosa Parks Barbie? One might take it as good news—more progress toward giving children a diverse set of heroes to look up to. As scholars have pointed out, however, the Barbie version of Ms. Parks’ story has been whitewashed. Instead of a devoted Civil Rights activist protesting for decades against racial inequality, Mattel tells children that Parks was only a tired woman who had led an “ordinary life” up until her famous refusal to give up her bus seat.

Why would the toy company want to politely ignore real, established history? It has something to do with the NYT Magazine’s recent 1619 series. That series, about the history of racial slavery in the British Colonies, has sparked a ferocious response among conservative historians and pundits. Perhaps most memorably, Newt Gingrich freaked out about it on Fox News.

As Gingrich declaimed,

The whole project is a lie. Look, I think slavery is a terrible thing. I think putting slavery in context is important. . . . I think, certainly, if you are an African-American, slavery is at the center of what you see as the American experience. But, for most Americans, most of the time, there were a lot of other things going on. There were several hundred thousand white Americans who died in the Civil War in order to free the slaves. The fact is that I saw one reference that The New York Times claims that the American Revolution was caused in part to defend slavery. That is such historically factually false nonsense that it’s embarrassing that The New York Times is doing this.

This leads us to our two big questions. First, why do conservatives—even history experts such as Rep. Gingrich—get so flustered over an extremely uncontroversial position like the one taken in the 1619 project? After all, among historians, the centrality of racial slavery in the founding of the United States is a given. And second, what does any of this have to do with a Rosa Parks Barbie?

My two cents: Over the years, conservatives have been very willing to expand the galaxy of American heroes. In addition to the traditional cluster of Washington, Jefferson, Franklin, and Madison, conservatives have been happy to add new heroes such as Martin Luther King Jr., Sacagawea, and, yes, Rosa Parks.

The idea that a mild-mannered “ordinary woman” could stand up to injustice fits in nicely with the traditional tale of heroic America. Sure, there have been problems—the story goes—but heroic Americans have always stepped up to solve them. Even the curse of slavery, Gingrich pointed out, was solved by the self-sacrificing heroism of “several hundred thousand white Americans.”

What doesn’t fit in is the real story of Rosa Parks. Parks, a life-long civil-rights activist, learned from radical institutions such as the Highlander Folk School, and campaigned against racism long past the 1950s. That real story raises questions most Americans are not comfortable confronting. For example, what were the connections between civil-rights activism and left-wing politics? Why did Parks feel a need to keep campaigning for racial justice long after the Montgomery Bus Boycott? Why was the second-class-citizenship she endured so entrenched and durable? What did the Civil Rights Movement leave unsolved?

All those questions point to a fundamental fact about American history that conservatives can’t abide. Instead of a flawed-but-improving land of truth and justice, these questions point to a vision of United States history in which the nation has always been fundamentally formed and guided not by heroism, but by racial (and other) hierarchies.

As I argued in my book about the history of educational conservatism, conservatives have drawn the line when it comes to questioning America’s heroic history itself. Any intimation that the United States has fundamental, formative flaws has always drawn ferocious criticism. Consider, for example, the reaction to a popular textbook series in the 1930s and 40s. Harold Rugg’s textbooks sold by the millions. But when rumors spread that Rugg’s books denigrated America’s unique awesomeness, they crossed a culture-war line.

One conservative critic, Bertie Forbes of Forbes Magazine fame, warned in 1940 that the textbooks guided teachers to criticize the greatness of the United States. When one middle-school teacher was asked by her students if the USA was the greatest country in the world, she looked at her Teacher’s Guide and responded, “No. . . there are several countries in Europe which have as good, if not better, form of government than ours.”

Forbes raises a stink, October, 1940

Not a particularly shocking statement, but it lit a fire under conservative Americans at the time. Sometimes literally. Soon, Rugg’s books were yanked from school bookshelves and rumors spread of book burnings in Wisconsin and upstate New York.

When it comes to Barbies and popular histories, then, we shouldn’t be surprised to find this third rail still firmly in place. We Americans are happy to add heroes to our list. We are happy to have Rosa Parks Barbies as well as Malibu ones. But as a whole we can’t stand to see the big story of our history challenged. We can’t and won’t tolerate public discussions that imply that there are any serious, fundamental, structural flaws in America’s past.