A major new study of social media sharing patterns shows that political polarization is more common among conservatives than liberals — and that the exaggerations and falsehoods emanating from right-wing media outlets such as Breitbart News have infected mainstream discourse.

Though the report, published by the Columbia Journalism Review, does an excellent job of laying out the challenge posed by Breitbart and its ilk, it is less than clear on how to counter it. Successfully standing up for truthful reporting in this environment “could usher in a new golden age for the Fourth Estate,” the authors write. But members of the public who care about such journalism are already flocking to news organizations like The New York Times, The Washington Post, and, locally, The Boston Globe, all of which have experienced a surge in paid subscriptions since the election of President Trump. That’s heartening, but there are no signs that it’s had any effect on the popularity or influence of the right-wing partisan media.

The CJR study, by scholars at the Berkman Klein Center for Internet & Society, at Harvard Law School, and the MIT Center for Civic Media, examined more than 1.25 million articles between April 1, 2015, and Election Day. What they found was that Hillary Clinton supporters shared stories from across a relatively broad political spectrum, including center-right sources such as The Wall Street Journal, mainstream news organizations like the Times and the Post, and partisan liberal sites like The Huffington Post and The Daily Beast.

By contrast, Donald Trump supporters clustered around Breitbart — headed until recently by Stephen Bannon, the hard-right nationalist now ensconced in the White House — and a few like-minded websites such as The Daily Caller, Alex Jones' Infowars, and The Gateway Pundit. Even Fox News was dropped from the favored circle back when it was attacking Trump during the primaries, and only re-entered the fold once it had made its peace with the future president.

The authors of the study refer to their findings as “asymmetric polarization,” and they point to some deleterious effects. The Breitbart-led sites were able to push the traditional media into focusing on Trump’s favored issue — immigration — and to frame it on their terms: overwrought fears about crime and terrorism. Clinton, on the other hand, was defined mainly by scandal coverage in the form of her use of a private email server, the attack on the American consulate in Benghazi, Libya, and the Clinton Foundation. The authors of the study, Yochai Benkler, Robert Faris and Hal Roberts of Berkman and Ethan Zuckerman of MIT, write:

It is a mistake to dismiss these stories as “fake news”; their power stems from a potent mix of verifiable facts (the leaked Podesta emails), familiar repeated falsehoods, paranoid logic, and consistent political orientation within a mutually-reinforcing network of like-minded sites.

Use of disinformation by partisan media sources is neither new nor limited to the right wing, but the insulation of the partisan right-wing media from traditional journalistic media sources, and the vehemence of its attacks on journalism in common cause with a similarly outspoken president, is new and distinctive.

Washington Post media columnist Margaret Sullivan, writing about the study earlier this week, recalled talking with a Trump voter in Pennsylvania who said she didn’t support Clinton because “I didn’t like how she stole those emails and it got people killed in Benghazi” — a perfect storm of misinformation.

But Sullivan’s prescription is unsatisfying. “There’s another way that the traditional press has allowed right-wing media to flourish — by moving too far to the left itself,” she writes. Though it’s true that studies show most mainstream journalists are liberal, she offers little evidence suggesting that the situation has changed much over the years, although longtime media observer Tom Rosenstiel did tell her that there are fewer Republicans in newsrooms than there used to be.

Besides, in contrast with the partisan right-wing media, mainstream journalists are dedicated to the proposition that facts should be verified and errors corrected. Let’s not forget that it was the Times that exposed Clinton’s email habits — an overblown story that almost certainly cost her the presidency when FBI Director James Comey reopened his investigation on the basis of zero evidence barely a week before the election.

Then, too, the kinds of people who share stories from Breitbart on social media are politically engaged in ways that the average Trump supporter is not. But never fear: the right-wing media machine is there for them, too. The current issue of the National Enquirer features two front-page photos of Trump and the headlines “How I’m Cleaning Up Obama’s Mess!” and “Amazing Secrets Behind Triumphant Capitol Hill Speech.” (Also: Michael Jackson was murdered.) I would quote from the Trump story, but that would require me to read it.

What's at issue here is not just asymmetric polarization but asymmetric news consumption. The left and the center avail themselves of real journalism, however flawed it may be, while the right gorges on what is essentially political propaganda — all the while denigrating anything that contradicts their worldview as “fake news.”

Doing a better job of listening to criticism and being open to change, as Margaret Sullivan suggests, is always a good idea. But it is hardly going to give rise to a new “golden age.”