Roger Ailes was a genius. He realized that short skirts and blond hair combined with heavy doses of racist fearmongering and hysterical patriotism could hook a cable TV audience of mostly old white male Americans, especially the type who thought of themselves as hardcore conservatives but who in fact were eager to get on board with the zaniest conspiracy theories – Barack Obama is a Muslim born in Kenya – as long as it vindicated and reinforced their pinched worldview.

Then Ailes turned around and scammed those same viewers by showing them promos for dubious products such as gold coins alongside ads for products those viewers actually needed: weight loss, psoriasis treatment, insurance and portable oxygen. The proceeds, plus a mountain of fees from cable and satellite distributors – to the tune of $4.42bn in quarterly revenue for Fox’s cable division – were passed straight up the corporate chain to Rupert Murdoch and sons.

It can be argued that Ailes’s political products were even more spurious than the emergency gold. Recent work by the Stanford academics Gregory J Martin and Ali Yurukoglu has indicated that Fox News was stunningly successful at helping to elect George W Bush twice, and the network remade itself as a state media arm for Donald Trump, two presidencies devoted to making sure rich people – not the core Fox News viewership – have the tools to stay that way.

Behind the scenes, we now know, Ailes was engaging in serial sexual harassment, and he presided over a culture that marginalized and demeaned women, the extent of which was a shocking discovery when it came to light through a lawsuit brought in 2016 by the former host Gretchen Carlson – shocking even given the blatant game of sexual objectification and titillation on display in most every Fox News broadcast.

But there was another side to Ailes, who died in May 2017. He was more than unusually good at television, and more than unusually committed to owning the liberals, and he knew a thing or two about human nature, and he was very ambitious, and he loved to be a star, and he never claimed to be a journalist. And you can’t argue with the popularity of the network he built or its influence.

Thus duty-bound, one wades into the Ailes life story, which is thankfully told with both journalistic verve and human sensitivity in the new documentary Divide and Conquer, directed by Alexis Bloom, who won a Producers Guild of America award for her 2013 film We Steal Secrets: The Story of WikiLeaks.

Should you miss Divide and Conquer, be advised that it is merely the leading edge of a breaking wave of cultural content centered on Ailes, with upcoming offerings including a Showtime series with Naomi Watts and Russell Crowe and an Adam McKay-directed film starring John Lithgow as Ailes and Charlize Theron as former Fox host Megyn Kelly, whose own story of harassment helped end Ailes’s career.

The Divide and Conquer film-makers set out to balance the story of Ailes’s brilliance with the reality of his corrosiveness, said Bloom.

“I think the two things coexist in reality, and you have to find some way to make them coexist in the film,” she said. “It’s not true to life if you come out that he’s just pernicious and monstrous. Neither that he was a genius. He was both.”

There’s a debate to be had about whether the film gets that balance right, considering the havoc wreaked by Fox News on the country, embodied by the current president. Political scientists have measured rapidly growing political polarization in the United States which has in turn been linked to the rise of siloed media of which Fox News is the apotheosis. That polarization has diminished the quality of the elected leadership while breeding a sense of alienation and suspicion among the populace.

While Divide and Conquer does not go deep on the changes wrought to America by Fox News, the film does a good job of getting former Fox News personalities to speak about Ailes, including Glenn Beck, whose interview on camera is a masterpiece of pseudo-insightful mumbo-jumbo.

Roger Ailes in Divide and Conquer: The Story of Roger Ailes. Photograph: Magnolia Pictures

“It’s easy to make somebody into a monster,” Beck says. “It’s hard to see that you’re on that path, too.” Unless … you aren’t?

“It wasn’t easy to get access,” said Bloom. “We never thought it was going to be easy. But those who had left Fox – it became easier when he died, because people really feared his litigiousness.

“People who’ve worked there have described it as a cult, and many are aware of the kind of repressive aspects of the workplace. But they’re incredibly well-paid, and Roger was famous for taking care of people.”

The film vividly tells the story of the lesser-known passages in Ailes’s life, including his foreshadowing work as president of the cable channel America’s Talking and his later, unsuccessful effort to jerk around the Hudson Valley town of Cold Spring when he moved there.

In a brilliant move, the film-makers cast a genderqueer actor, Babette Bombshell, as Ailes’s body double, for a scattering of re-enactment scenes. It has the ring of poetic justice, given Fox News’s record of homophobia and fear-mongering on transgender issues.

But most powerfully, the film puts the camera on women telling their stories of how Ailes sexually harassed them. The stories have previously been printed, but it is galvanizing to meet the women onscreen and watch them as reveal the true story of Ailes, who resigned amid accusations of harassment by more than 20 women.

People in TV are enamored by what they do, and the film leans heavily on television people, producer types, speaking in hushed tones about “the genius of Roger” and his knack for camera positioning and closeups and the number of seats in the audience.

“There is a Citizen Kane quality to his life,” somebody says at one point, and at another a comparison between Ailes and John Wayne is supported by footage of the movie star. We also learn that Ailes was a hemophiliac whose “daily life was a fear of annihilation” which supposedly “allowed him to understand the fears of other people”.

Or maybe he was just an uncommonly talented and unscrupulous television producer. Do we really care what made Roger Ailes tick?

“The big disappointment was that he used his talent and his media savvy to build something that drove a wedge,” says Felycia Sugarman, a former producer at Ailes communications, in the film. “To me that’s pretty devastating.”