Mourners pay tribute at a makeshift memorial on the Las Vegas Strip for the victims of this week’s mass shooting. (Eugene Garcia/European Pressphoto Agency/EFE)
Media Columnist

Well-intentioned warnings to journalists were circulating early this week as the news of the Las Vegas massacre broke.

The Society of Professional Journalists urged accuracy, fairness and respect.

Poynter Institute cautioned reporters to avoid speculating on mental illness and told editors not to use images that glorify the shooter.

But the purveyors of viral lies weren’t listening to this good advice, and never will.

Facebook and Google served up disinformation on their all-powerful platforms. They promoted rumors that not only named the wrong gunman but blamed his supposedly liberal politics.

“Social media has become totally weaponized,” Kara Swisher, co-founder of the technology news site Recode, said at a conference Tuesday. The former Wall Street Journal and Washington Post reporter couldn’t be more right.

And the managing editor of the fact-checking website Snopes.com warned that “it’s getting more polarized.”

“There’s this mad scramble to paint the guy as a Democrat or a Republican, so they can cheer,” Brooke Binkowski told the Guardian. “A lot of this is pushed by trolls deliberately to muddy the conversation.”

The worst of it this week probably was the falsehood spread on the anonymous message site 4chan that the shooter was someone named Geary Danley, using his Facebook “likes” to show that he was a Trump-hating liberal. It quickly made its way into prominence through the big social media sites. The Las Vegas tragedy is only the latest example. We’re only now beginning to get a grip on social media’s role during last year’s presidential election.

CNN reported Wednesday that Russian-backed advertising on Facebook — damaging to Hillary Clinton — was targeted at her campaign’s weak spots in Michigan and Wisconsin. She lost both states by narrow margins, and they were important to Donald Trump’s electoral college triumph.

“The ads employed a series of divisive messages aimed at breaking through the clutter of campaign ads online, including promoting anti-Muslim messages,” according to the CNN story.

These platforms couldn’t be more powerful or influential. (Facebook now has 2 billion monthly users. Google’s parent company is worth more than $600 billion.) Millions get their news — or what looks like news — from these behemoths.

At a time when the truth is under assault, including from the Oval Office, it’s clear that the weaponizing trend couldn’t be more damaging.

What’s far less clear is what should be done.

This week, the platforms made their usual weak-tea excuses, accompanied by vague pledges of reform — delivered in the equally familiar robotic prose:

“Unfortunately, early this morning we were briefly surfacing an inaccurate 4chan website in our Search results for a small number of queries. Within hours, the 4chan story was algorithmically replaced by relevant results. This should not have appeared for any queries, and we’ll continue to make algorithmic improvements to prevent this from happening in the future.”

Facebook’s response had a similar mind-numbing tone.

To be fair, they’ve made a start. Under fire, Facebook has announced that it will hire 1,000 people to review ads. (This after dismissing a host of editorial employees not too long ago.) In a full-page print ad in Wednesday’s Washington Post, Facebook said it would fight election interference. And both companies have supported news literacy efforts and journalistic initiatives.

Granted, an obvious solution is elusive.

“No amount of ‘fixing’ Facebook or Google will address the underlying factors shaping the culture and information wars in which America is currently enmeshed,” wrote Danah Boyd in Wired.

Undeniably true, as is her point that it’s hard to define “fake news” in a terribly divided society. (The president’s definition, for example, is anything — true or false — that paints him in a negative light.)

Still, there is such a thing as verifiable reality. There is such a thing as valid, fact-based journalism. And while it may be hard to pin down, there is such a thing as truth.

And there’s the opposite of these things: hoaxes, conspiracy theories, flat-out lies in the form of news stories, advertising from a foreign adversary meant to sway a presidential election.

Given the platforms’ outsize role in these problems — and their immense wealth — they need to step up with some serious solutions and stop blaming their own technology.

I continue to believe that elevating the judgment of experienced, intelligent news experts — editors, by any other name — must be a central part of the answer.

The tech giants need to fully grasp what’s happening here, and devote their attention and plentiful resources to addressing it. And soon — before their weaponized platforms kill what’s left of our democratic society.

For more by Margaret Sullivan, visit wapo.st/sullivan