Facebook co-founder Mark Zuckerberg waves during the Asia Pacific Economic Cooperation forum in Lima, Peru, on Saturday. (Esteban Felix/AP)

Two days after the election of Donald Trump, Mark Zuckerberg found himself on the hot seat.

At a tech conference, an interviewer grilled the Facebook chief executive about the fake news that proliferates on the platform, suggesting that it had swayed the election toward Trump. One widely shared story, for example, said that Pope Francis had endorsed the Republican nominee.

Zuckerberg scoffed:

“Personally I think the idea that fake news on Facebook, which is a very small amount of the content, influenced the election in any way — I think is a pretty crazy idea. Voters make decisions based on their lived experience.”

But since then, under fire (including from President Obama, who railed against the fake-news epidemic last week), Facebook has taken some positive steps.

During a Facebook live discussion, reporter Caitlin Dewey explained how fake news sites use Facebook as a vehicle to function and make money. (The Washington Post)

Late Friday, Zuckerberg posted about how he grasps the seriousness of the problem and outlined the ways Facebook might deal with it. He mentioned third-party verification services; better ways for users to flag hoaxes; and efforts to keep fake-news websites from getting rich on advertising dollars.

That’s welcome progress.

Now it’s time for a bolder move: Facebook should hire a top-flight executive editor and give that person the resources, power and staff to make sound editorial decisions.

Zuckerberg may not want to call this person an editor, since he has been insistent that Facebook isn’t a media company. He sees it as a technology company, a platform for connectivity. And indeed, Facebook itself does not produce news content but merely allows its community members to share their own offerings — whether baby pictures or hoaxes about political candidates.

That’s fine. Call this person the chief sharing officer or the engagement czarina.

Whatever the title, Facebook needs someone who can distinguish a Pulitzer Prize-winning photograph from child pornography and who can tell a baseless lie from a thoroughly vetted investigative story.

What rules the roost at Facebook is “engagement.” To oversimplify: The more an item is shared among your friends, the more likely you are to see it.

Clearly, that’s not nearly enough. What’s needed to kill fake news is ruthless fact-checking, gut-checking and a big helping of common sense.

The Silicon Valley behemoth, with its billion-plus users, is a major news source — for some demographic groups, the leading one. Its influence is only going in one direction: ever upward.

Understandably, Facebook doesn’t want to turn into the world’s censor in chief. And it shouldn’t and doesn’t have to.

When Zuckerberg said recently that identifying truth is hard, Ben Smith, chief editor of Buzzfeed, had a ready answer:

That might be the case, he said, “for algorithms and epistemologists. But it’s something that professional journalists are asked to do every day, and it’s not actually that complicated.”

It comes down to judgment — the kind that can’t be done by complicated code or by relying on well-intentioned but vague “community standards.”

The need for editorial judgment at Facebook didn’t start with this post-election finger-pointing. It has been growing for many months.

Last summer, for example, a Minnesota woman named Diamond Reynolds used her smartphone to live-stream a horrific scene onto Facebook: Her boyfriend, Philando Castile, had been fatally shot by a police officer. Her post was removed for about an hour — Facebook said that was because of a technical glitch — then restored.

Then, in September, Facebook deleted Nick Ut’s Pulitzer Prize-winning photograph of a Vietnamese girl fleeing a napalm attack because it violated the platform’s standards on nudity and child pornography. When global outrage followed, it, too, was restored.

Emily Bell, director of the Tow Center for Digital Journalism at Columbia University, has called on Zuckerberg to change his mind about Facebook’s role in the media ecosystem.

“By acknowledging that Facebook can and should play a more active part in editing — yes, editing — its own platform, and hiring actual people to do so, Zuckerberg will further the civic commons as well as address a growing problem of how people perceive Facebook,” she wrote in Columbia Journalism Review.

And last week, author Jeff Jarvis and tech entrepreneur John Borthwick, writing on Medium, offered 15 ways to combat the fake-news epidemic. Among them: hire some editors, “not to create content, not to edit . . . but instead to bring a sense of public responsibility to their companies and products.”

Editors, of course, are far from infallible. Most of them would be quick to admit that. But this move would put someone in charge — at a high level — who could help journalists and technologists talk to one another and who could make decisions based on sound judgment.

Would it be enough to stamp out fake news? Certainly not.

But Facebook’s appointment of an executive editor would be a step forward, bringing accountability and good sense where it’s sorely needed. It would also set a good example for other tech companies and social platforms that are grappling with the same problems.

Another “pretty crazy idea”? Maybe so. But one whose time has come.

For more by Margaret Sullivan visit wapo.st/sullivan