The arc of history is long. But does it bend toward a Martin Luther King Jr. movie?

For years, filmmakers have tried to get King dramatizations off the ground, with directors as prestigious as Oliver Stone and Jonathan Demme failing to gain traction. Whether because of lack of financing, the absence of a good script or simply the failure of the cinematic planets to align, arguably the most important American of the 20th century, not to mention the story of the movement he helped lead, has gone un-memorialized in the dominant narrative medium of our time.

That omission was on its way to being rectified with a vengeance earlier this year, when no fewer than five King-related projects were underway in Hollywood. With two dropping out and two merging into one, it seems that at least one major King motion picture and a cable miniseries are finally on the way to screens big and small.

In April, DreamWorks Studios and Warner Bros. announced they would join forces to produce an as-yet-unnamed King drama, which is being written by Kario Salem (“The Score”). Both studios had King projects in development, with DreamWorks having secured the cooperation of King estate chairman Dexter King in 2008. After some initial squabbling with siblings Martin and Bernice King, in 2009 they joined their brother on the project, announcing that DreamWorks would have access to their father’s papers, life rights and rights to his speeches. (DreamWorks executives expect to see Salem’s most recent draft this fall.)

Meanwhile, last year, Lee Daniels, fresh off directing the Oscar-nominated “Precious,” indicated that his next film would be “Selma,” about pivotal events in that Alabama city in 1964, with David Oyelowo in the lead. And in February, Paul Greengrass announced that he would write and direct “Memphis,” about King’s last days and the search for his assassin.

But in April, Universal Pictures, which had agreed to produce and distribute “Memphis,” abruptly confirmed it would not back the film, a reversal that stunned Greengrass and producer Scott Rudin, who thought they’d be filming in June. Although the studio attributed the change of heart to timing issues, Deadline Hollywood reporter Mike Fleming revealed that Andrew Young — the former Atlanta mayor and U.N. ambassador and close King confidant — had read the “Memphis” script and raised objections with Universal executives, which may have informed their decision to scuttle the film.

Young reportedly objected most strongly to Greengrass’s depiction of a character based on Georgia Davis Powers, who, according to her memoir, was with King at the Lorraine Motel the night before he was shot. Reached at his office in Atlanta, Young said he’d forgotten why he’d objected to Greengrass’s script, but that, like “Selma,” which he also read, as well as other projects, he felt “Memphis” distorted and sensationalized King’s legacy.

“For instance, I read some script where they had [King] and Ralph [Abernathy] in Selma, drinking beer and smoking pot,” Young said. “Well, that could not have happened. Every room we ever stayed in was bugged, and if there was ever any incidence of Martin Luther King and drugs, they would have locked him up so quick, you’d never hear from him again. Yet these arrogant screenwriters want to try to humanize him in a way that they . . . project their weakness on to him.”

Those familiar with Greengrass’s script, as well as with his taut truth-based dramas “Bloody Sunday” and “United 93,” insist that “Memphis” is anything but prurient or salacious. “I thought it was really compelling and very important,” said Fleming of the “Memphis” screenplay. “It’s a little bit warts-and-all, but I think it’s a very honorable depiction of Dr. King’s struggle. It’s not a preachy biopic.”

For his part, Greengrass expressed confidence that “Memphis” would make it to the screen. “We’ll set about making the film in due course,” he said in an e-mail. “The good thing is this: The way the world is turning right now makes King’s legacy and ideas increasingly more relevant. Look at what’s happened in the Middle East right now. What do we see? Millions of disenfranchised mainly young people pressing for radical non violent change. . . . This great, unstoppable ideal that King developed in the U.S., is alive and moving across the world today in profound ways.”

(In May, “Selma” executive producer Brad Pitt said that, although the film was “in limbo at the moment,” he was confident that “Lee would get it done.”)

Perhaps the longest-running attempt to bring King’s work to the screen may finally be on the verge of realization: An adaptation of Taylor Branch’s trilogy “Parting the Waters,” “Pillar of Fire” and “At Canaan’s Edge” is in development at HBO under the production auspices of Oprah Winfrey’s Harpo Films. The seven-hour miniseries, which is being adapted by “Pacific” screenwriter Robert ­Schenkkan, has the potential to capture the complexities, characters and scope of an era that stand in danger of being reduced to stock figures in a standard feature film. After two decades of stops and starts bringing his Pulitzer Prize-winning history to the screen, Branch said, “I’m more curious than anybody on Earth to see what Robert Schenkkan has come up with.”

He continued: “We still have this vast, empty canvas from that period, and the first film that breaks through needs to have some balance. It needs to invite other films to come through.” He cites “Mississippi Burning” as an example of a film that had a chilling effect on dramas that sought to tackle the subtleties of the civil rights era, and not only because it cast the FBI in a heroic light, which many observers considered a scandalous distortion of history.

“The movie squandered an opportunity,” Branch said, because “it killed the [civil rights workers] in the first scene. So you had no sense of why they did what they’d done and why it was so transformative. You didn’t feel the movement.” That densely layered sweep of history may be best served with the long-form storytelling that HBO has perfected with such miniseries as “The Pacific” and “John Adams.”

Surprisingly, one of the reasons why audiences have gone so long without a King movie may be the King family itself: Understandably seeking to have only the most flattering portrait presented for the permanent record, family members haven’t hesitated to contact filmmakers of what they deem to be negative portrayals, suggesting that without rights to King’s life and speeches, the projects might be on thin legal ice. Although few filmmakers would admit it, surely some have backed off after these threats, if only to avoid a public relations disaster.

Still, DreamWorks partner and co-chairman Stacey Snider said the studio wanted freedom to quote liberally from King’s writings and speeches, without fear of infringing on copyrights. “As a movie executive, usually we want to make things shorter,” she said. “In this case, we want the audience to be in the swell of his oratory. . . . If we are giving it our very best effort to be comprehensive and righteous to his memory, then we have to be comprehensive and righteous to his words.”

There’s little doubt that DreamWorks, whose co-founder and partner Steven Spielberg directed such epics as ­“Schindler’s List” and “Saving Private Ryan,” is capable of making what Andrew Young said he was looking for in a King movie: “the kind of thing that Sir Richard Attenborough did on ‘Gandhi.’ ” That was a classy, stirring evocation of Gandhi’s work, surely, but some critics thought it presented an overly idealized version of a more complicated man.

With the King family executive-producing the DreamWorks-Warner Bros. project, the question arises as to which nuances, if any, of King’s life and character might be left on the cutting-room floor. It seems more likely than ever that the arc of history will include a King movie. The question is whether it will bend toward depicting the man or the myth.