In just the past few weeks, I’ve seen two notes — one from a bright college student, the other from a serious Hollywood agent — in which a nonfiction book was casually referred to as a “novel.” Ask any literature professor, and he or she will tell you that, more and more now, students don’t bother to distinguish.

I can’t help viewing this as a dark omen for our culture. Sure, it could be a simple matter of a word losing its meaning, but I think it hints at a deeper erosion in the society that these past four, painful years have laid bare.

This is the “epistemological crisis” Barack Obama discussed, with characteristic eloquence, in a recent interview promoting his new memoir — which is not, by the way, a novel.

“If we do not have the capacity to distinguish what’s true from what’s false,” the former president told the Atlantic’s Jeffrey Goldberg, “then by definition the marketplace of ideas doesn’t work. And by definition our democracy doesn’t work.”

Agreed. But where Obama fears a lack of capacity, I worry just as much about a lack of faith.

It might not be simply that Americans don’t understand the distinction between what’s real and contrived, or that they can’t be bothered to learn the terms that describe these things. It’s more that we no longer trust anyone in authority to arbitrate which is which.

And so naturally these terms lose their meanings. When you’ve lost your faith that anything presented as “nonfiction” can be irrefutably true, then everything in the culture becomes essentially novelistic — a tale invented by its author, at best a mix of fact and conjecture.

The result is a collapsing boundary between truth and fiction in the public mind. Look at how some of our finest news organizations (this one included) covered the fourth season of Netflix’s “The Crown” — a brilliant show, by the way — by offering lengthy fact-checks of each episode, as if the series were a political debate.

Did Queen Elizabeth really plant an ugly story about Margaret Thatcher? Did Prince Charles really cheat on Princess Diana from the moment they married?

Does it matter? Not at all, really, unless you expect to get your history from TV and movies, which I don’t recommend.

Having told the same political story in a nonfiction book and on screen, I can tell you that it’s impossible to avoid invention in a cinematic version, and the amount of invention — whether 10 percent or 90 percent — is irrelevant.

One form is true, and the other is art. The first is meant to be believed; the second only to be appreciated and considered.

In grappling with social media and the spread of misinformation, a lot of us have argued that a critical part of the solution is what we call media literacy — essentially teaching citizens how to navigate the various forms of content and figure out which are credible and which serve some ideological or financial agenda.

But maybe the first issue we face is more basic than that. Before we can help anyone sort out truth from fiction, maybe we first have to persuade them that such distinctions even exist.

We have to be able to agree as a society that journalism and entertainment represent not different perspectives on the same truth, but rather truth vs. something else entirely.

Of course, my liberal friends have no trouble accepting the premise that conservatives in the Trump era have contributed mightily to this trend. Trump’s “fake news” mantra was intended to obliterate the notion of objective truth. His embrace of “alternative facts,” as his adviser Kellyanne Conway famously put it, made factual relativism the official policy of American government.

But it’s not only Trumpism that contributes to that relativism. We in the media do, too, with increasingly judgmental — which is to say, leftist — news coverage and a constant stream of interpretive reporting. So do liberal schools and historians, who now declare history to be a kind of “Choose Your Own Adventure” of dueling narratives, rather than a fixed, if complicated, set of facts.

Maybe that’s a reasonable response to the monolithic version handed down by previous generations. But it invites the uncomfortable question: Is history one long novel, too? Is anything clearly nonfiction now?

This is what the Trump moment has left us with. This is the twisted legacy of a created-for-TV character who could not distinguish between statecraft and entertainment, whose instinct in life — it’s too charitable to call it a strategy — has always been to confuse the line between reality and fiction, until people find it so exhausting to separate the two that they mostly give up trying.

We can’t give up. Because there are novels, and there is nonfiction. There is fact, and there is entertainment.

And a country that stops caring about the difference is a country whose story does not end well.

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