On October 10, 1999, The Los Angeles Times published a special issue of its Sunday magazine devoted entirely to the opening of the Staples Center arena in downtown LA. Apparently unbeknownst to the Times editorial staff, including the writers and editors who put the magazine together, the paper had struck a deal with the owners of the Staples Center to split the profits from the ads sold in the issue.

When the staff found out about the arrangement, they rebelled. More than 300 reporters and editors signed a petition demanding that the publisher apologize, which she did. In a sweeping, 12-part post mortem, the paper’s media critic, David Shaw, noted that “many in The Times newsroom see the Staples affair as the very visible and ugly tip of an ethical iceberg of ominous proportions—a boost-the-profits, drive-the-stock-price imperative that threatens to undermine the paper’s journalistic quality, integrity and reputation.” The deal had violated one of the most sacrosanct principles in serious journalism, sometimes referred to as the “firewall” or separation of church and state: the business department should have no influence on editorial decisions.

Things have changed a great deal in the decades since the Staples Center incident. Social media has become a dominant forum for discourse and news distribution. The leaders of social media companies insist that they are not publishers but merely technological conduits for user-generated content. And yet at the same time they proudly advertise the critical role they play in modern communication and access to information. The decisions they make about what material should be seen by whom have a greater impact than anything The Los Angeles Times could ever have dreamed of.

But the social media industry has yet to articulate a philosophy of how the pursuit of advertising revenue should be balanced against other social values. Facebook, in particular, does not appear to have anything like a separation of church and state. An explosive investigative series in The Wall Street Journal last week provided fresh evidence of what happens when there’s nothing preventing the business side from overriding the people working on quality control. In one case, the Journal reported, researchers inside the company studied certain changes to the News Feed ranking algorithm that had been designed to increase “meaningful social interactions.” When the changes were introduced, CEO Mark Zuckerberg had publicly declared they were the “right thing” to do, even if they sacrificed user engagement and time spent on the app. The researchers, however, found that the features, which included amplifying posts deemed most likely to be reshared, inadvertently ended up boosting “misinformation, toxicity, and violent content.” According to documents reviewed by the Journal, when a leader from Facebook’s integrity department proposed a solution to the company’s business department—that is, to Zuckerberg—he declined to implement it. He didn’t want to sacrifice user engagement.

In response to stories like these, Facebook points out that it has increased its investments in safety and content moderation in recent years. This week in a press release it announced that it employs “40,000 people working on safety and security, up from 35,000 in 2019 and a four-fold increase from 10,000 in 2016.” (That’s roughly one employee for every 71,000 users, by the way.) But, as the Journal and other reports have repeatedly shown, at crucial moments, those teams are overruled as decisions about safety, content moderation, and enforcement are made by the executives in charge of the company’s growth and lobbying operations. Facebook, in other words, needs its own version of journalism’s firewall.

In fact, the lesson social media companies should take from traditional media is much broader. The most interesting thing about journalism’s separation of church and state is that it’s self-imposed. No federal statute says a newspaper must keep its advertising operations walled off from coverage decisions. It’s a value that crystallized in the 1920s, when American journalists adopted a commitment to objective, nonpartisan reporting. As historian Michael Schudson explains in his book Discovering the News: A Social History of American Newspapers, this was a key moment in the professionalization of journalism, as reporters and editors “accepted a definition of what it meant to be independent from the state and the market.” In theory, nothing is stopping Jeff Bezos from interfering with how The Washington Post, which he owns, covers Amazon, which he founded. In practice, he’d be risking a wave of resignations and a major dilution of the value of the Post’s brand. No self-respecting reporter wants readers to think they’re doing the bidding of the sponsor. (By all accounts, Bezos has been scrupulously hands-off since buying the paper in 2013.)