In February of this year, Michael Cohen, the president’s personal lawyer, testified before Congress that he assisted in burying stories of Trump’s affairs. In today’s everything-is-on-fire context, the scene barely registers now, but any long-term vision of American democracy would consider it remarkable: the personal lawyer to the president of the United States, a former reality TV star ensnared by campaign finance laws after paying former Playboy models for their silence in the 2016 presidential election. The mind-boggling convergence of politics and celebrity, soap opera and political formality, public and private, money and low-brow titillation would seem unprecedented – that is, unless you’ve followed the story of the paper involved in suppressing stories of Trump’s affairs: the National Enquirer, a gore rag turned sensationalistic newsstand staple which has long been at the forefront, for better or for worse, of America’s celebrification of news.

That’s the story covered in Scandalous: The Untold Story of the National Enquirer, a new documentary on the history of an ethics-blurring American gossip magazine – and, by extension, on American celebrity culture, and the issues and storylines that could produce, as one former Enquirer staff member recalls, the goal of “a triggering response”.

Scandalous traces the literal slash-your-competitors’-tires style of journalism practiced at the National Enquirer through some of the biggest and most breathlessly devoured stories of the last several decades: the deaths of Elvis and comedian John Belushi (of which coverage by the Enquirer led a source, perhaps unfairly, to be jailed for injecting drugs), the OJ Simpson trial, the death of Princess Diana and the Clinton impeachment saga. The film portrays a publication proudly putting the service of readers – in particular, a tantalizing Page One for the fictional conception of Missy Smith in the grocery aisle of Kansas City or Yonkers or anywhere – over journalistic ethics; the paper routinely paid sources for information, built networks on personal betrayal and savaged most celebrities it covered.

Director Mark Landsman was neither fan nor reader during the National Enquirer’s heyday, in terms of circulation, in the 1980s, or even in recent years. But his interest piqued during the 2016 presidential election, when he found himself “baffled” while “waiting in the supermarket checkout lines staring at the racks of headlines from the National Enquirer describing Hillary Clinton in various stages of near-death or hooked on narcotics”, he told the Guardian. The incongruity of the coverage prompted him to ask, what the hell is going on here? But it wasn’t until a year later that a chance encounter turned the question into a film pitch. Landsman was having dinner with a family friend when her father, Malcolm Balfour, started regaling the table with stories from his old job back at the upstart tabloid in the early 70s. Balfour, it turns out, was one of the first of the scrappy, ethically dubious tabloid reporters poached from UK publications to bring the National Enquirer some chops.

“His stories were kind of mind-blowing: stories of checkbook journalism, unconventional sourcing, bribes, disguises, espionage and all kinds of scurrilous tactics,” Landsman recalled.

So Landsman dove into the paper’s evolution. Starting with Balfour, Landsman “tried to arrange for as much access to their world as I possibly could”. The network of Enquirer alumni was “this very interesting series of dominoes either falling or refusing to fall”, said Landsman. With the help of an “ace” archival producer, Aileen Silverstone, he obtained extensive footage from the paper’s early years and 1970s newsroom.

Though the National Enquirer itself has existed for over 90 years, Scandalous begins with its modern iteration, when the New York magazine was bought (allegedly with money from mob boss Frank Costello) by Generoso Pope Jr in the 1960s. Pope pivoted the National Enquirer squarely into gore – horrific car accident pictures, murder victims’ blood on the floor – but shifted gears with the advent of suburbia. In a stroke of marketing brilliance, he directed the magazine to mirror America’s obsession with celebrities, their weight and diets, and true crime shockers, and convinced grocery stores to stock them in checkout lines. Now an impulse buy with kernels of truth exploded into titillating, if “fake-ish” in substance, headlines, the Enquirer’s circulation soared to 5.9 million people a week by 1978; when the magazine put a shadily obtained photo of Elvis Presley in his coffin in 1977, the subsequent cover sold 6.7m copies.

An issue of the National Enquirer featuring Donald Trump on its cover at a store in New York. Photograph: Mary Altaffer/Associated Press

The gems uncovered by Silverstone in the archive don’t refute these first-person accounts, according to Landsman; rather, it’s “like taking a time capsule back”, to a looser, more wild west era of tabloid journalism, chain-smoking and all. “It had this crazy beehive of activity with cigarettes and ashtrays,” Landsman said. “I just thought, this is a time and place that no longer exists any more and won’t exist any more.”

This was before, of course, Ronan Farrow’s revelations on the National Enquirer’s practice of so-called “catch and kill”, a particular version of silencing in which a publication buys the exclusive rights to a story with the intent of burying it indefinitely. Farrow’s stories revealed that the owner of the National Enquirer, David Pecker, worked with Trump’s personal lawyer Michael Cohen to arrange catch-and-kill payments during the 2016 election to former porn star Stormy Daniels and Karen McDougal, who both had affairs with Trump during his marriage to Melania. “It was bizarre,” Landsman said of continuing his research into the history of the National Enquirer during the period when the publication’s tactics were themselves front-page news. (Besides the Trump and Cohen hearings, there was also Pecker’s deeply miscalculated attempt to blackmail the Amazon founder, Jeff Bezos, with leaked photos).

The film does not feature any first-person testimony from the contemporary iteration of the National Enquirer; reaching out to AMI was “a dead end”, Landsman said. Instead, Scandalous also features commentary from such journalistic heavyweights as the New York Times White House reporter Maggie Haberman, Watergate-era legend Carl Bernstein, New Yorker writer Ken Auletta and Keith Kelly of the New York Post. Their inclusion was “intentional from the first moment of the film … we didn’t want to make this film in a vacuum”, explained Landsman. “We didn’t want this to be an echo chamber of just Enquirer voices. We really wanted to understand, from a first person perspective, what quote-unquote ‘legitimate journalists’ were experiencing at the time that Enquirer over history was breaking certain stories. And the effect that they felt that it had – bad, good or otherwise – on journalism as a whole.”

That effect, it’s revealed, is a weirdly prescient echo of today’s dominant headlines – the National Enquirer, long chummy with Trump, essentially created his image as a celebrity famous for being famous. Its agnostic respect of power fostered coverage of deeply troubling allegations – Bill Cosby’s affairs, Michael Jacksons’s child abuse – long before capital J journalism outlets investigated them seriously. And its dogged pursuit of the lowest-common-denominator personal life stories, particularly in politics, are now de rigueur in wide swaths of coverage, online and on TV. As one former staffer put it, by now, the traditional press has “out-Enquirered the Enquirer”.