Every night for 19 years, CBS Evening News anchor Walter Cronkite ended his newscast with the same assurance to his viewers: “And that’s the way it is.”

And that’s the way it is. Only in a world without cable news, without Breitbart, without Twitter trolls, and without late-night satirists would a journalist dare make so bold and sweeping a claim. But to paraphrase Cronkite, that’s the way it was in broadcast television. No “alternative facts.” No alternative realities. And barely any alternative voices. Before cable television and the internet, the news was the news, composed of the same top stories and delivered in the same gravel-voiced tenors regardless of the outlet. Anchors might add occasional touches of flair (like a signature sign-off), but there was nothing truly novel in the news media. If ABC was Coke, then CBS was Pepsi. Each had its own flavor, but the ingredients were pretty much the same.

The homogeneity of broadcast television first showed signs of cracking in the 1980s, when CNN, the country’s original 24-hour news channel, hit the airwaves. The big three networks, perhaps too comfortable in their dominance, were quick to dismiss CNN as a fringe player, privately calling it Chicken Noodle News. But when CNN was the only network to broadcast live from inside Iraq during the Persian Gulf War, big audiences tuned in, foreshadowing the growth of cable news and the rise of MSNBC and Fox News.

These newcomers challenged the primacy of the “Big Three” networks in the 1990s, but the real disruption to legacy media’s distribution monopoly came with the internet. As the gates to mass publishing fell, new flavors of journalism began to emerge — from the Drudge Report’s politicized journalism to Vice’s gritty immersive reporting — and the democratized web became home to a wider spectrum of voices and perspectives, including those critical of the mainstream media. Suddenly, anyone with an internet connection and a Twitter account could help turn #NBCFail into a trending hashtag (as happened during the network’s coverage of the 2012 Olympics), and media criticism could go viral, giving readers’ isolated misgivings an opportunity to evolve into collective mistrust. And unlike the pre-internet era, dissatisfied audiences now had somewhere else to go.

Arguably, no trend has reshaped the media landscape more dramatically than this one — the proliferation of news options on an ungated web. And in early 2017, perhaps nowhere were the impacts of this new reality more apparent than in the White House briefing room.

Professional journalism lost the power to enforce its own rules.

On January 17, three days before Donald Trump’s presidential inauguration, the White House press corps sent an open letter to Trump offering him a glimpse of what he could expect the next four years. “While you have every right to decide your ground rules for engaging with the press, we have some, too,” the letter read. “It is, after all, our airtime and column inches that you are seeking to influence. We, not you, decide how best to serve our readers, listeners, and viewers.”

The letter came only six days after Trump famously shouted down CNN reporter Jim Acosta in his first press conference as president-elect, calling Acosta’s network “fake news” following its coverage of an investigation into Trump’s relationship with Russia. The incident sparked outrage in the media and inspired the combative letter, which promised that “we,” the press corps, would decide how much airtime to offer to Trump spokespeople, that “we” would set the ground rules about “off the record” interviews, and that “we” would even work together to hold Trump’s administration to account.

“You have tried to divide us and use reporters’ deep competitive streaks to cause family fights,” the letter explained. “Those days are ending. We now recognize that the challenge of covering you requires that we cooperate and help one another whenever possible. So, when you shout down or ignore a reporter at a press conference who has said something you don’t like, you’re going to face a unified front.”

If the promise for collaboration and a “unified front” among dozens of competitive news organizations seems almost beyond belief, that’s because it was. In reality, the letter was penned by Kyle Pope, editor and publisher of the Columbia Journalism Review, who was expressing the unity he wished existed in Washington’s press corps. Pope’s use of the collective “we” was misleading, but it was also anachronistic, a throwback to an era when journalism’s rules and standards — the ones taught in journalism schools, enshrined in codes of ethics, and reinforced by press clubs and award programs — were universally accepted across the news business.

That journalism — Cronkite’s journalism — came with a sense of collective identity, a sense of “we” that no longer exists in the age of cable news and the internet. Consider the fact that shortly after shutting down Jim Acosta, Trump took a question from Matthew Boyle, a reporter from the alt-right news site Breitbart. Regardless of the well-intentioned screeds by journalism critics like Pope, a Breitbart employee is about as likely to repeat CNN’s question as Trump is to duplicate Obama’s climate policies. (The odds might not be zero, but they’re pretty darn close.)

Pope’s open letter reflects a broader failure by mainstream journalists to recognize the limitations of their influence on the internet. In 1997, for example, at the dawn of the digital age, the American Society of Magazine Editors (ASME) released a set of “Guidelines for New Media” that instructed publishers to clearly identify advertising on their websites. According to John Motavalli, author of Bamboozled at the Revolution, ASME’s leadership believed “the traditional magazine world would still dominate cyberspace,” as it had in print publishing. Instead, the organization’s guidelines were “widely mocked and ignored,” offering an early glimpse at what would happen to professional norms on the internet, where journalism’s core values, including “balance” and “neutrality,” could no longer be taken for granted.

News publishers (and audiences) gravitated toward the political poles.

In August 2016, 24-year-old Tomi Lahren became the latest fiery ideologue to “break the internet” when she delivered a three-minute rant about biracial quarterback Colin Kaepernick’s decision to protest racial discrimination by kneeling during the national anthem. Lahren, then only two years removed from college, referred to Kaepernick as a “whiny, indulgent, attention-seeking crybaby” and proceeded to blast him for choosing to “sit on a bench and bitch and moan about [his] perceived oppression.”

That kind of rhetoric would be a fireable offense at any legacy broadcast network, but Lahren’s segment didn’t appear on ABC or CBS. It appeared on the Blaze, a right-wing digital network founded by former Fox News personality Glenn Beck. And her audience loved it. Within weeks, the clip had been viewed more than 65 million times on Facebook, helping make Lahren one of the most talked-about political commentators of 2016. “I do not bullshit, I am genuine and authentic,” she said in an interview with the Guardian. “I don’t say these things to go viral or to be controversial, but I say things that a lot of people wish they could say but are fearful of saying.”

Lahren is only the latest partisan news commentator to find fame on the internet, where anyone with a smartphone and internet access can engage in the content creation, curation, and distribution work once reserved for card-carrying journalists. Digital media celebrants argue that such democratization has been a net positive for society, pointing to social media’s role in the Arab Spring revolutions, the triumphs of crowdsourced reporting, and the growth of alternative media as evidence that digital media really can be a force for democratic good.

However, even the web’s most ardent defenders must acknowledge that the digital revolution also came with a dark side. Comment sections and digital aggregators like Reddit and Digg found themselves overrun by racist, sexist, and xenophobic internet trolls. Social media platforms wrote algorithms that bifurcated the web into insular filter bubbles. And opportunistic upstarts dressed up propaganda to look like real news and then fed it to partisan news consumers who couldn’t get enough. “We built the structures for hate to flow along the same pathways as knowledge, but we kept hoping that this wasn’t really what was happening,” social media scholar danah boyd wrote for Points. “We aided and abetted the media’s suicide. The red pill is here. And it ain’t pretty.”

The red pill also isn’t new, of course. Within months of President Reagan’s 1987 decision to roll back the Fairness Doctrine, a Federal Communications Commission policy that required broadcasters to commit airtime for exploration of diverse and opposing viewpoints on controversial themes, a young talk show host named Rush Limbaugh was being syndicated on 56 stations across the United States. Within four years, Limbaugh was on more than 600 stations, reaching huge audiences with his then-novel brand of no-holds-barred conservative commentary. Subsequent efforts to reinstate the Fairness Doctrine in the 1990s were unsuccessful (in no small part due to the political mobilization of Limbaugh’s supporters), and talk-show hosts like Sean Hannity and Laura Ingraham on the right and, to a lesser degree, Alan Colmes and Stephanie Miller on the left followed Limbaugh’s game plan — and shared his success — by catering to the political extremes.

The trend toward polarization that started on talk radio only accelerated on the internet, where left-wing progressives turned to MoveOn and ThinkProgress, disaffected conservatives embraced Breitbart and InfoWars, and the mainstream outlets found themselves stuck in the middle, espousing what Jay Rosen calls a “view from nowhere” — one that’s subject to criticism from the left and the right. The result, according to the Pew Research Center, is an increasingly fractured news and information ecosystem: “When it comes to getting news about politics and government, liberals and conservatives inhabit different worlds,” a 2014 Pew study found. “There is little overlap in the news sources they turn to and trust.”

Most recently, this polarized media ecosystem has been weaponized by blatant propaganda, which uses fabrication and fiction to appeal to partisan audiences. During the 2016 presidential campaign, these sensational fake news stories sprinted around the internet, driving millions of clicks that in turn generated thousands of dollars for their unscrupulous publishers. One of those publishers, a recent college graduate named Cameron Harris, estimates he made about $1,000 an hour writing up content for his bogus news site ChristianTimesNewspaper.com, which posted headlines like “Protesters Beat Homeless Veteran to Death in Philadelphia” and “NYPD Looking to Press Charges Against Bill Clinton for Underage Sex Ring.”

Interestingly, Harris isn’t a political ideologue, nor are the Macedonian twentysomethings who, according to Buzzfeed, created more than 100 bogus news sites focused on the U.S. election. For these profiteers, fake news is just business, and clicks are the currency. “The info in the blogs is bad, false, and misleading,” one Macedonian student acknowledged. “But the rationale is that ‘if it gets the people to click on it and engage, then use it.’”

The brazenness of the propaganda (and the extent to which news consumers shared it, uncritically, on social media) took many people by surprise in 2016, but as Bill Kovach and Tom Rosenstiel warned as early as 2001, the economic conditions that fueled this movement have in fact been building for years. “For the first time in our history,” they wrote, “the news increasingly is produced by companies outside journalism, and this new economic organization is important. We are facing the possibility that independent news will be replaced by self-interested commercialism posing as news.”

Rolling Stone’s Matt Taibbi similarly interpreted the rise of propaganda as a symptom of market forces. “I think for a long time now, Americans have been consuming facts as consumers,” he told Trevor Noah on the Daily Show. “I think we shop for facts the same way we shop for hats, shoes, or radial tires; we shop for the things we like. And I think people are choosing their own reality now.”

This trend toward a post-truth society has alarmed political leaders across the world, including President Obama, who spent much of his lame-duck period speaking out about the perils of fake news. In November 2016, Obama told HBO’s Bill Maher that “it’s very hard to figure out how we move democracy forward” without “some common baseline of facts,” and during a press conference in Germany, he warned that “if we are not serious about facts and what’s true and what’s not…[and] if we can’t discriminate between serious arguments and propaganda, then we have problems.”

The president even devoted a section of his farewell speech to the issue of truth in the media, urging Americans not to retreat into their own bubbles, “surrounded by people who…share the same political outlook and never challenge [their] assumptions.” He continued:

The rise of naked partisanship, and increasing economic and regional stratification, the splintering of our media into a “channel for every taste”—all this makes this great sorting seem natural, even inevitable. And increasingly, we become so secure in our bubbles that we start accepting only information, whether it’s true or not, that fits our opinions, instead of basing our opinions on the evidence that is out there. And this trend represents a third threat to our democracy…Without some common baseline of facts, without a willingness to admit new information and concede that your opponent might be making a fair point, and that science and reason matter, then we’re going to keep talking past each other. And we’ll make common ground and compromise impossible.

Because news publishers no longer control society’s media and information gates, they are largely powerless to stop the virality of fake news and the fracturing of news audiences on the internet. However, there is at least one digital-era gatekeeper that could help reverse the tide if it wanted to: Facebook. In 2016, a Pew Research Center study found that 67 percent of Americans are registered Facebook users, and 66 percent of those users get news on the site — up from 47 percent only three years earlier.

As a result of the platform’s growing reach, Facebook’s algorithms now increasingly shape the news diets of millions of Americans. And in 2016, those algorithms served up lots of garbage. According to an analysis by Buzzfeed, the 20 most viral fake election stories generated a total of 8.7 million shares, reactions, and comments on Facebook, compared to only 7.4 million shares, reactions, and comments for 20 of the top-performing legitimate election stories.

It’s true, of course, that human users — not algorithms — were the ones choosing to share those stories with their friends. But by allowing investigative reports from the New York Times to appear alongside half-baked propaganda from the Conservative Tribune — and by providing few visual cues to distinguish the two — Facebook enabled a problem that critics argue it might have easily fixed. As techno-sociologist Zeynep Tufekci wrote for the New York Times, “When the company decided it wanted to reduce spam, it established a policy that limited its spread. If Facebook had the same kind of zeal about fake news, it could minimize its spread, too.” Another Facebook engineer agreed, telling Buzzfeed that the company could slow fake news if CEO Mark Zuckerberg simply gave the order. “There is a lot more we could be doing,” the unnamed employee said, “using tools already built and in use across Facebook to stop other offensive or harmful content.”

So will Zuckerberg answer the call? Many critics say he has a moral obligation to do so, citing the role Facebook plays as a modern news and information filter and invoking the company’s “responsibility” to the public. Their hope is that Facebook, along with fellow digital media giants Twitter and Google, might yet embrace their role as gatekeepers of the modern web and choose to filter out fake and hyperpartisan news, doing for journalism what journalism can no longer do for itself. However, this white-knight logic neglects an important point: The internet’s new gatekeepers aren’t journalists — and they have plenty of reasons to keep it that way.

The internet’s new gatekeepers don’t share journalism’s values.

During an August 2016 school visit in Italy, an inquisitive student asked Zuckerberg whether his company intended to become a news editor. The question came at a moment of soul searching for the social media giant: Three months earlier, Gizmodo had broken the news that Facebook’s “news curators” were deliberately stifling conservative news sources on the platform’s Trending Topics feed, sparking an uproar of criticism from Republicans and leading to Facebook’s eventual decision to replace its human curators with supposedly “neutral” algorithms.

The snafu underscored Facebook’s increasingly influential role as a gatekeeper of the modern web, and for a fleeting moment in May 2016, when Zuckerberg used the word “newsworthy” to describe his vision for Trending Topics, it seemed that Facebook might start approaching this gatekeeping role with a greater sense of journalistic responsibility. In Italy, however, Zuckerberg doused those hopes with a splash of reality. “No, we are a tech company,” he told the student, “not a media company.”

Zuckerberg has appeared to give some ground since the election, announcing a range of efforts to make fake news less viral on the platform; launching the Facebook Journalism Project, an initiative intended to “establish stronger ties” with the news industry; and publishing a 3,600-word manifesto affirming Facebook’s commitment to “reduce sensationalism and help build a more informed community,” among other lofty goals. But none of these modest steps even remotely suggest that Facebook plans to assert “news judgement” in the way that professional journalists have for more than a century. In fact, Zuckerberg’s vision for the company (he has called Facebook a “platform for all ideas” and repeatedly expressed a desire “to make the world more open and connected”) is fundamentally at odds with this heavy-handed gatekeeping approach, and so is his business model. In 2016, Facebook raked in $26.9 billion dollars from digital advertising, a 57 percent increase from 2015 that helped the company turn a record profit of $10.2 billion, up 177 percent. And it’s surely no coincidence that this spike coincided with the explosion of fake and hyperpartisan news on the platform. The reality is that sensationalism and partisanship are not bugs in Facebook’s platform so much as features of the machine — a machine that works best when audiences become glued to their screens, no matter what brings them there. As John Hermann wrote for the New York Times:

Unlike traditional media organizations, which have spent years trying to figure out how to lure readers out of the Facebook ecosystem and onto their sites, these new publishers are happy to live inside the world that Facebook has created. Their pages are accommodated but not actively courted by the company and are not a major part of its public messaging about media. But they are, perhaps, the purest expression of Facebook’s design and of the incentives coded into its algorithm — a system that has already reshaped the web and has now inherited, for better or for worse, a great deal of America’s political discourse.

So, sure, Zuckerberg might be earnest about combatting blatant propaganda on Facebook, if only to ward off public criticism and prevent a revolt by advertisers. But the idea that Facebook will assume responsibility for curating and filtering news in the “public interest” is a pipe dream. As long as Facebook’s bottom line remains beholden to clicks, likes, and shares, the public should expect its infrastructure and algorithms to reward the types of content that deliver on these metrics. That’s good news if you run a hyperpartisan news blog or specialize in “trendy” social videos, but it’s bad news for the rest of the news media, including a pillar of American journalism that’s already in trouble: the watchdog press.

This article is an excerpt from Reimagining Journalism in a Post-Truth World: How Late-Night Comedians, Internet Trolls, and Savvy Reporters Are Transforming News, forthcoming from Praeger in January 2018. The next installment of this series will address the decline of the watchdog press and the increasingly cozy relationship between journalists and political elites.