Supporters try to shield Jonathan Butler, who was on a hunger strike, from members of the media as he leaves after addressing a crowd following the announcement Monday that University of Missouri System President Tim Wolfe would resign. (Jeff Roberson/AP)

It’s now official (or at least entirely self-evident): Just about everyone hates the news media.

For decades, conservatives took it as an article of faith that the mainstream media had it in for them. From President Richard M. Nixon’s parting shot at reporters in 1962 (“You don’t have Nixon to kick around anymore, because, gentlemen, this is my last press conference”) to Ben Carson’s attack on the skeptical coverage of his life story, conservative suspicion of the media’s presumed liberal bias has cured like cement, becoming hard and unyielding.

But liberals are catching up. Democratic candidate Bernie Sanders has railed against the alleged sins of the “corporate media” during this year’s campaign. Sanders’s main opponent, Hillary Rodham Clinton, has conveyed suspicion, if not outright hostility, of the news media since her days as first lady.

And then there was Monday’s spectacle in Columbia, Mo., where a group of face-freshed college students bullied and badgered reporters seeking to cover a protest at the University of Missouri. “Hey, hey, ho, ho, reporters have got to go,” the young people chanted, echoing a campus rallying cry once aimed at a president, Lyndon B. Johnson, who presided over an unpopular war.

“Everyone sees [the media] as too arrogant,” said Tim Graham of the Media Research Center, a conservative watchdog organization. “Everyone sees them as bad listeners. Everyone sees them as dumbing down the news for consultants teaching them to goose ratings and page clicks.”

No, not everyone distrusts the “media” — a hugely imprecise terms incorporating innumerable print, broadcast and digital sources — but the trend hasn’t been the friend of journalists for years. Only 4 in 10 Americans told Gallup’s pollsters this year that they had “a great deal” or “a fair amount” of trust and confidence in the media’s ability to report the news “fully, fairly and accurately.” The figure tied all-time lows from 2012 and 2014.

Conservatives still evince far greater skepticism than liberals, but that gap is closing. Trust in the media among Democrats fell to 54 percent last year, a 14-year low. The figure for Republicans was 32 percent.

The big question is why.

Gallup itself says the media’s tumbling public esteem roughly parallels the loss of trust for other institutions, such as Congress, banks, organized religion and the presidency. But the polling organization also suggests that some of the media’s wounds are self-inflicted: “Major venerable news organizations have been caught making serious mistakes in the past several years, including the scandal involving former NBC Nightly News anchor Brian Williams.”

Academics and others who study the media see a more complex series of interactions at work.

The short version might be something like this: Digital innovations, such as social media and the Internet generally, have democratized the media, putting the power to report — sometimes not all that well — in the hands of many more people. The digital revolution has also weakened the traditional media, those professional gatekeepers who once forged a general consensus, right or wrong, about what constituted the day’s news.

As a result, the “media” have gotten bigger, broader, more opinionated, partisan and sensational — and arguably less capable.

“It bereaves me to say this, but [the public’s dim view of the media] is a perfectly understandable reflection of the fact that most of the media are not doing things as well as they once did,” said Edward Wasserman, the dean of the University of California at Berkeley’s graduate journalism school. “Coverage is not as thoughtful, penetrating and complete as it once was. You don’t have the news staff, the news hole, the foreign bureaus, the statehouse reporting that you once did. . . . It’s the rare exception that a news organization has gotten better, not worse,” over the past decade or so.

The tyranny of ratings and clicks — news sites can now instantly measure the ebb and flow of readers and viewers — might be a culprit, too. “I suspect there are many good news organizations that reward producers whose work draws the most attention,” regardless of other criteria, Wasserman said.

On the other hand, particularly during the campaign season, criticism of the media spikes, and not all of it is justified, said Paul Fletcher, president of the Society of Professional Journalists. “The press is an easy target,” he said. “Candidates like to control their messages, and they don’t like it when journalists ask them questions that might derail their messages. It’s easy to characterize a legitimate question as a ‘gotcha’ because it’s a way to escape answering or a means to try to change the subject and attack the motives of the questioner.”

Georgetown scholar Jonathan Ladd takes a longer view. He blames a convergence of factors — the inevitable “perfect storm” — for the decline of trust in the media over the past 3 1 /2 decades. New technology, starting with cable TV in the 1980s, brought more media — and more criticism of the media from the new entrants, he said. Deregulation, particularly the elimination of the restrictive Fairness Doctrine in 1987, brought still more opinionated voices to the air (Rush Limbaugh, for one), intensifying the public’s doubts about the media.

By the time the Internet matured, media-on-media criticism was rife, making public distrust all but inevitable, said Ladd, the author of “Why Americans Hate the Media and How It Matters.”

The bad news, he said, is that more partisan media may have driven a more polarized electorate. But that doesn’t mean the process will continue without end. “I think we’re starting to come to a new equilibrium,” Ladd said. “It’s settling down. I think there is a core who want the kind of institutional news that NPR, The Washington Post and the New York Times provide. There’s a large audience for that.”