Months ago, when former New York City mayor Mike Bloomberg said he would not run for president, a palpable feeling of relief flooded the global newsrooms that bear his name.“The sound of 2,700 exhaling,” as the quip had it.Now — with the 77-year-old billionaire’s decision to get in the Democratic race after all — that relief is over, replaced by a collective gasp.The situation is worse than many expected.Initial decisions about how to handle 2020 coverage are stunning ones. They put Bloomberg’s many talented journalists, especially those in Washington and New York, in a compromised position.The policy, as detailed over the weekend in a memo from top editor John Micklethwait: journalists will not dig into Bloomberg himself — or his charitable endeavours, business practices, family, etc — or into his Democratic rivals. They will cover developments in the campaign on a more superficial level.Micklethwait: “We will look at policies and their consequences. We will carry polls, we will interview candidates and we will track their campaigns, including Mike’s. We have already assigned a reporter to follow his campaign [just as we did when Mike was in City Hall]. And in the stories we write on the presidential contest, we will make clear that our owner is now a candidate.”Bloomberg News also will publish other organisations’ investigations, sometimes in summary form.However, for now, they will continue to investigate Donald Trump.These plans “relegate his political writers to stenography journalism”, Kathy Kiely, Bloomberg News’ former politics director, told the Associated Press on Sunday. She left the news service in 2016, when Bloomberg was considering a presidential run.And Megan Murphy, former Washington bureau chief of Bloomberg News, tweeted that she was presented “with a near identical ‘memo’ during his 2016 flirtation”, and found it unacceptable. “I was very clear that I would quit the second it ever saw the light of day.”To those insiders, the dangers were all too clear.There’s more: at Bloomberg Opinion, unsigned editorials — the institutional voice of the organisation — are being discontinued altogether, and prominent members of the opinion staff, including top editors David Shipley and Tim O’Brien, the Trump biographer whom I’ve often quoted in my Washington Post column, will take leaves of absence to join the boss’s campaign.That, too, raises dicey questions: What happens if Candidate Mike is unsuccessful — these journalists just blithely spin back through the revolving door into their old jobs? What happens if he becomes president? They leave journalism altogether?But it’s the news-side issues that raise the most vexing ethical questions.Built into good journalism is independence. It’s a requirement, the very foundation — the sine qua non, since we seem to like three-word Latin phrases these days. “Without which, not”: the essential element.Making a crucially important area of coverage off-limits saws away at that foundation, leaving everything that remains in an unstable state.This isn’t entirely new at Bloomberg. The long-held policy is that the organisation doesn’t investigate its owner’s wealth, personal life, family and so on.That was true during his three terms as New York mayor; it wasn’t good then, either, but the stakes are far higher now.And at times, the billionaire has hinted at why:“Quite honestly, I don’t want all the reporters I’m paying to write a bad story about me,” he half-jokingly told a radio interviewer late last year, as he suggested that he might end Bloomberg News’ political coverage should he decide to run.He added: “I don’t want them to be independent.”Bloomberg could have entirely recused himself from decision-making or influence at the news organisation — saying, in effect, “cover me like anyone else and do it with journalistic integrity”.Journalism “without fear or favour” — associated with a written statement of purpose by New York Times publisher Adolph S. Ochs in 1896 — could have been the aim.Is this realistic when a mighty billionaire’s future is at stake? Granted, it’s always difficult for news organisations to cover themselves and the powerful people who own or run them.There is always the risk of self-censorship — but yes, it’s possible.These are not perfect parallels, but The Washington Post has written many tough-minded stories about Amazon, whose founder, Jeff Bezos, owns this news organisation but leaves the editorial decisions to Executive Editor Martin Baron. And I never experienced an iota of editorial meddling from The Buffalo News chairman and owner Warren Buffett when both the newsroom and the editorial board reported to me for almost 13 years.That, however, is not the plan, which doesn’t bode well for what’s ahead, especially if Bloomberg is successful.We already have a rich-guy president who thinks the tried-and-true rules that underpin American democracy aren’t made for him and who doesn’t exhibit a core understanding of the accountability role of an independent press.The Bloomberg Way is the company’s well-known guide for journalists at the news organisation, an intended manifesto for best practices.Failing to fairly cover the most important story of our time — with built-in provisions for complete independence — may be the Bloomberg way at the moment. But it isn’t the right way.• Margaret Sullivan is The Washington Post’s media columnist. Previously, she was The New York Times public editor, and the chief editor of The Buffalo News, her home-town paper