Over the past several decades, important feature films have been made about most of the historical and cultural touchstones of post-World War II America, from the Vietnam War and John F. Kennedy’s assassination to Watergate and women’s liberation. But there’s been one glaring exception: The breadth and depth of the civil rights movement — the most influential social and political force of the 20th century, not just on American life but throughout the world — has never been represented in the dominant narrative medium of our age.

Until now.

A number of films about the civil rights movement are in various stages of development. The first out of the gate will be “Lee Daniels’ The Butler,” which stars Forest Whitaker as Cecil Gaines, an African American man born a sharecropper’s son in Georgia, who comes to Washington in the 1950s and eventually serves eight U.S. presidents as a White House butler. (The film is based on a Washington Post article written by Wil Haygood in 2008.)

Directed by Daniels and featuring a cavalcade of stars in cameo roles, “The Butler” largely focuses on Gaines’s family life and interactions with the presidential families he serves. But it also chronicles the burgeoning movement taking shape on the streets far beyond 1600 Pennsylvania Ave.

While Gaines silently observes Dwight D. Eisenhower grappling with school desegregation, Lyndon B. Johnson preparing to sign the 1965 voting rights act and Richard M. Nixon plotting against the Black Panthers, his son Louis (David Oyelowo) is sitting in at a Nashville lunch counter, joining the Freedom Riders, crossing paths with Martin Luther King Jr. and eventually joining the Panthers himself.

Similar scenes have been portrayed as backdrops or perfunctory montages in previous films. But “The Butler,” which arrives in theaters Friday, is the first major feature film to capture the full sweep and scope of the civil rights movement, including its global reverberations. (Gaines retires during the administration of Ronald Reagan, who is seen vetoing sanctions against South Africa’s apartheid regime.) For that reason, if “The Butler” does well at the box office, projects about the same era that have been stalled over the past several years may find renewed momentum. Conversely, should the film flop, some of Hollywood’s most pernicious myths — most pointedly that there are not wide audiences for historical dramas in general and black films in particular — will become all the more entrenched.

“Yikes,” said Daniels, who visited Washington last week, when he considered “The Butler” as a cinematic and cultural bellwether. Upon reflection, however, it’s a burden he was happy to accept. “If it opens the doors for other civil rights films and African American dramas, right on,” he said. “That’s a great thing. Anything to help the cause.”

At least four major film or television projects about the civil rights movement are in the works: DreamWorks is developing an untitled Martin Luther King Jr. biopic. “Memphis,” about King’s final days and the hunt for his assassin, is back on track with director Paul Greengrass and producer Scott Rudin after being dropped by Universal Pictures in 2011. Director Ava DuVernay is preparing to direct “Selma,” about the 1965 voting rights campaign (a film that Daniels himself once intended to direct). And “America: In the King Years,” based on Taylor Branch’s trilogy of civil rights books, including the Pulitzer Prize-winning “Parting the Waters,” is in development as a seven-part mini-series at HBO.

Each of these projects has been gestating over several years, and each of them has been stymied or derailed at some point, sometimes because of disputes over King’s life rights, sometimes because financing fell apart, sometimes because a filmmaker got cold feet. But all of them have been subject to the tyranny of “comparables” in the entertainment business, whereby executives green-light or drop movies based on the performance of projects with similar themes and casting configurations.

“In any business, part of the job is to mitigate your risk,” Edward Saxon told me in 2007. Saxon, an independent producer, worked with Jonathan Demme 20 years ago when Demme sought to adapt “Parting the Waters” as a feature film. “So you say, ‘Okay, if this superhero movie does even half of what that superhero movie did, it’ll be successful.’ But when you tried to call up comparables on a movie like ‘Parting the Waters,’ they [didn’t] exist.”

That math might be changing. Consider: In 2009, Daniels’s drama “Precious: Based on the Novel ‘Push’ by Sapphire” became an unexpected art-house hit, and earned Daniels an Oscar nomination. Last year, “Lincoln,” Steven Spielberg’s historical drama about the 16th U.S. president, exceeded even Spielberg’s commercial expectations. This year, the Jackie Robinson biopic “42” and the micro-budget contemporary drama “Fruitvale Station” have both done well at the box office, earning more than $95 million and $10 million, respectively.

And it’s no coincidence that “The Butler” is opening the same month as did “The Help,” the period drama about African American domestic workers and their white employers that became a box-office smash in 2011 — and that shares more than a little thematic DNA with “The Butler.”

Eugene Allen saw eight presidents come and go over three decades serving on The White House staff. On Background's Nia-Malika Henderson talks with Wil Haygood, who wrote a book about Allen and whose reporting inspired the film version of "The Butler." (The Washington Post)

Knowing the importance of comparables, “The Butler” screenwriter Danny Strong crossed his fingers when “The Help” came out, watching its commercial journey closely. “I was writing ‘The Butler’ simultaneously and I was very worried: Could this hurt getting ‘The Butler’ made?” Strong recalled last week. On the strength of the $180 million “The Help” earned at the box office, he added, “we were able to go to private financiers and say, ‘Look at what a hit this was.’ It was enormously helpful in giving people confidence that we could quote unquote be the next ‘Help.’ And if we can make half as much as ‘The Help’ did, we’re a hit.”

Of course, the reason why “The Butler” was financed independently — the film boasts more than 30 producers, each of whom ponied up some money for the $25 million production — is because Sony, the studio that originally optioned Haygood’s article, has almost entirely gotten out of the business of producing modestly budgeted dramas. Like every other major movie company, Sony’s revenue is increasingly coming from overseas, where tent-pole pictures such as “Spider-Man” and “Men in Black” habitually rake in the euros. And like every studio, Sony has been operating under the stubborn belief that black films don’t do well overseas — despite success stories like “The Help,” which earned a respectable $42 million in non-U.S. markets.

For that reason, even with such recognizable stars as Whitaker, Oprah Winfrey and Cuba Gooding Jr., Daniels felt compelled to cast the biggest white stars he could find, “name actors that meant something overseas, so that we could finance the film.” (“The Butler” features Jane Fonda, Robin Williams, John Cusack and Alan Rickman in cameo roles.)

Despite the fact that the studio didn’t go forward with the project, Daniels credits Sony’s co-chairman, Amy Pascal, for seeing value in the story in the first place. “I’m not upset with her, I’m upset with the system,” he said, adding that the studios’ recalcitrance is “an incredible testament to Hollywood underestimating the intelligence of America.”

Branch, for one, is eager to put the “black doesn’t travel” shibboleth to rest. “To me, it’s just a matter of intuition that that’s wrong, because the civil rights movement went abroad so strongly,” he says. “The Solidarity movement against the Soviet Union was modeled on sit-ins. They were singing ‘We Shall Overcome’ in Prague and in South Africa. . . . I am convinced that in Germany and in India and Asia, a good story that crosses racial barriers and shows the potential of democratic freedom will have an enormous market, not necessarily because it’s black, but because it’s in the larger sphere of people growing.”

Branch says he’ll be watching how “The Butler” does domestically and, perhaps most crucially, internationally. “There are a hundred movies about that era that might come crowding behind the first successful one.”

Branch also thinks the election of Barack Obama represented a shift that is only now being seem in movies, a sentiment shared by “Selma” director DuVernay — who notes that a wide range of movies about African Americans are being released this year, including “Fruitvale Station,” the pre-Civil War-era drama “12 Years a Slave,” and “Black Nativity,” a modern-day musical. DuVernay isn’t looking to “The Butler” as an augury of “Selma’s” fortunes once it’s ready to make a distribution deal. “I would say it’s much less about one film as opposed to an overall collective energy around what’s real, what’s viable and what’s relevant and worth being told,” she said.

Whether it’s a function of comparables, cultural progress, changes in the global film business or the Obama effect, the zeitgeist seems to be shifting. The result is that one of the most vibrant, meaningful, potent and richly dramatic eras in American history may finally find the cinematic foothold it has been denied for far too long. As Daniels told me when I asked how “The Butler” got made in spite of the obstacles: “You can’t stop the universe from doing what is meant to happen.”