Long exalted as one of the greatest achievements of cinema, Citizen Kane has suffered the fate common to canonized art: It has become familiar and safe. To be sure, the lore around the film often fixates on how controversial it once was. As a filmic roman à clef about William Randolph Hearst, the film naturally angered the powerful press baron and his many allies in Hollywood, who spared no effort in trying to suppress it. Gossip columnists ran scurrilous stories designed to destroy director Orson Welles and others involved in the production. MGM mogul Louis B. Mayer even made a bid to buy all the prints with the goal of destroying them.

But the personal spite of long-dead plutocrats is not necessarily relevant to contemporary audiences. More pertinent, but often ignored, is the fact that the movie was a product of the Popular Front culture of the 1930s and ’40s, the once-robust alliance between liberals and leftists to fight fascism. William Randolph Hearst, the onetime populist who in the 1930s devolved into a Red-baiting anti–New Deal reactionary, was the perfect target for Popular Front outrage. In Orson Welles’s voluminous FBI file, one agent made this critique of the movie: “Citizen Kane is nothing more than an extension of the Communist Party’s campaign to smear one of its most effective and consistent opponents in the United States.”

As was its wont, the FBI was too quick to conflate communism with broader radicalism. But the law enforcement agency was right to note that Welles, while making the film, had been shaped by an energetic left-wing environment. This is a fact that later critics, who focused on the inventive film techniques in Citizen Kane, often ignored. As Michael Denning noted in his magisterial history The Cultural Front (1996), “Many of those who celebrate Citizen Kane as a film masterpiece distance Welles from the culture of the Popular Front. Formalist and auteurist critics have generally ignored Welles’s political aesthetic.”

One of the singular virtues of David Fincher’s new movie Mank (now screening on Netflix) is that it recuperates the context that made Citizen Kane not just a venerable biopic about a vainglorious media mogul but also an urgent intervention against homegrown authoritarianism. Mank, about the travails of writer Herman Mankiewicz as he writes the first draft of Citizen Kane, is both an account of the making of Citizen Kane and an extended pastiche of Citizen Kane. Shot in black and white, with many off-kilter camera shots as a distancing device and moving back and forth in time, Mank mimics Orson Welles’s signature directorial style even as the narrative undercuts some of the Welles legend.

The least interesting part of Mank is its half-hearted litigation of the long-standing dispute over authorship of Citizen Kane, with collaborators Welles and Mankiewicz both claiming primary authorship. When the film won the Academy Award for best original screenplay in 1941, neither Welles nor Mankiewicz attended the ceremony. Mankiewicz said later that if he had been there to pick up the Oscar, he would have said, “I am very happy to accept this award in Mr. Welles’s absence, because the script was written in Mr. Welles’s absence.” Mank, following in the footsteps of Pauline Kael’s famous 1971 polemic “Raising Kane,” takes the same stance: Mankiewicz was a mistreated writer and Welles a credit hog.

The truth is more complicated. Mankiewicz was crucial, not just because he wrote the first draft but also because he had been a longtime crony of William Randolph Hearst and his mistress Marion Davies. Throughout the 1930s, Mankiewicz had spent many an hour as a dinner guest at San Simeon, Hearst’s palatial estate. In writing the script, Mankiewicz drew not only on the vast journalism that surrounded Hearst but also an intimate awareness of Hearst and Davies in their daily life.

Welles took Mankiewicz’s script and not only rewrote it but, more crucially, retold it with cinematic flare. New Yorker critic Richard Brody makes a judicious apportionment of credit when he argues, “Mankiewicz’s work was fundamental, and Welles’s revisions were transformative.” This sort of fair-mindedness is absent in Mank, where Welles, played with Mephistophelian aplomb by Tom Burke, is a fiendish, wheedling purchaser of souls.

Unjust to Welles, Mank redeems itself with its rounded, multisided portrait of Mankiewicz, a full-bodied presence thanks to Gary Oldman’s performance. Although only 43 in 1940 while working on Citizen Kane, Mankiewicz already looks decades older, an alcoholic wreck of man. His quick wit, once the toast of Broadway, keeps Mankiewicz not only employed writing scripts but a guest much sought after by the rich and famous. Hence his standing invitation to dine with Hearst and Davies. But Mankiewicz keeps self-sabotaging himself with bilious quips. Even as he plays the clown, he has enough dignity to resent his status as a court jester to plutocrats.

Even though Mankiewicz can make a ducal salary writing for the movies, he knows he doesn’t share the class interest of Hearst or the studio heads. When the Depression hits, Louis B. Mayer (Arliss Howard) quickly abandons his robust vulgarity and delivers an unctuous, smarmy speech to his MGM “family” asking them to take a rollback in pay (which he falsely claims will be returned to the workers in good times).

The cynical Mankiewicz is cagey enough to roll his eyes at Mayer. But the contradictions in Mankiewicz’s own position come to a head when he sees Hearst and the Hollywood ruling class close ranks in 1934 and use every means fair and foul to destroy Upton Sinclair’s socialist bid to become governor of California. In particular, they use Hollywood magic to produce deceptive radio ads and newsreels, a precursor to disinformation of our own age. (David Fincher has a long-standing fascination with media manipulation, as seen in his best movie, The Social Network).

During the election, Mankiewicz comes alive to his own complicity with the system and the fact that his preferred role as a clown is just another form of acquiescence to the status quo.

It’s Mankiewicz’s awareness of, and discomfort with, his own status as the well-paid pet of the rich that fueled the writing of Citizen Kane. He was enough of an insider to write about the world of Hearst with authority—but enough of an outsider to see through its comforting lies and pernicious politics.

Citizen Kane wasn’t the work of just one man—either Welles or Mankiewicz—but the product of a whole troupe of creators all shaped by the Popular Front. These creators all knew how theater and Hollywood worked, which made them sensitive to the fact that showmanship can often be used in the service of fascism. There’s a peculiar kind of critical empathy in Citizen Kane: The movie peers inside Charles Foster Kane’s soul even as it exposes his political foulness.

In a 1945 speech, Welles said, “Fascism, we know, sells itself by making its appeal to the emotions rather than to reason, to the senses rather than to the mind. Showmanship is fundamental to the fascist strategy.” Welles, Mankiewicz, and their army of collaborators were no mean showmen themselves, which made them all the more sensitive in their portrait of a reactionary mogul. This is the crucial but often forgotten political background to Citizen Kane that Mank has made visible to a modern audience.