"Everything that happened in the White House that we see in the movie, that all happened," insists Daniels, the Philadelphia-born-and-bred filmmaker. Dramatic license has been taken regarding aspects of Allen's family life and relationships, but as for the events depicted inside 1600 Pennsylvania Ave. . . . all true.
Because Allen, who died in 2010 at age 90, was black, a product of the segregated South, the pivotal events of the civil rights movement held particular resonance for him. The Butler, opening Friday, is a history lesson - from the perspective of someone shaped by a nation's legacy of racial injustice.
"American history is the civil rights movement, period," states Daniels, the great-grandson of a slave. "From slavery to Obama today."
So a black man trained to discreetly see to the needs of whites is there as Dwight D. Eisenhower grapples with desegregating Central High School in Little Rock, and as John F. Kennedy sends Army troops to quell rioting white students when the order came down to integrate the University of Mississippi. Among the many actors who give cameos as the presidents and first ladies are John Cusack as Richard M. Nixon; Liev Schreiber as Lyndon B. Johnson; Alan Rickman as Reagan; and Jane Fonda is his wife, Nancy.
For Wil Haygood, the Washington Post reporter whose 2008 front-page story about Allen caught the interest of Hollywood producer Laura Ziskin, the story of the White House butler was "fable-like" and astonishing.
"He was in the Oval Office and heard the echoes and the ripples of the Emmett Till murder, the Medgar Evers murder, the missing civil rights workers - Goodman, Schwerner, Chaney," says Haygood, whose book, The Butler: A Witness to History, is just out.
"He was in the White House and heard the echoes and the ripples of the four young schoolgirls bombed to death at the 16th Street Baptist Church in Birmingham. He was in the White House and witnessed up close the reverberations of the assassinations of Bobby Kennedy, John F. Kennedy, Martin Luther King, and Malcom X. He was in the White House and heard the ripples of the Watts riots, of the Chicago riots, of the Newark riots."
For Haygood - and, he says, for Ziskin - it was essential that this story come to the screen with its title character at the center as the fulcrum.
Other movies - The Help, The Long Walk Home - have addressed America's history of racial conflict and inequity. But those civil rights stories turn "overwhelmingly" in the direction of the white characters, Haygood notes.
"It seems as if the African Americans were minimalized. It's very painful to watch those types of movies. And Laura Ziskin said to me, 'This will be a movie about the butler. And its gaze will stay on the butler.' "
(The official title, Lee Daniels' The Butler, represents a compromise with the Motion Picture Association of America, which reportedly told the distributor, the Weinstein Co., that it couldn't call the film The Butler because of a 1916 silent short with that title - coincidentally by another Philadelphian, cinema pioneer Siegmund Lubin.)
For Daniels, who grew up in West Philadelphia, The Butler represents a turn in his career.
Accustomed to shepherding his own projects to the screen - from Monster's Ball, which won Halle Berry an Oscar, to Precious, which received six Academy Award nominations, including best director and best picture - Daniels was a hired gun on this project. Ziskin, who died in 2011, had been talking to Steven Spielberg about directing The Butler. But Spielberg went on to Lincoln instead, and Ziskin contacted Daniels.
The script, by Danny Strong, who is white, was already in place. "It was great," says Daniels. "But I just felt it needed to have more of an African American sensibility."
Inevitably, it got an infusion of Daniels' sensibility, too. Though The Butler doesn't pulsate with the in-your-face, bucket-of-fried-chicken audacity of Precious, the director's fingerprints are still visible - especially in the stormy encounters between Cecil's wife, played by Oprah Winfrey, and Terrence Howard's character, a rascally family friend. The tensions between Cecil and his son (David Oyelowo), who becomes a Freedom Rider, a follower of King, and then a Black Panther, also vibrate with Daniels-esque intensity.
A line of dialogue equating America's sad saga of slavery with the Nazi concentration camps of World War II is classic Daniels - searing, provocative.
"For 200 years, my people were killed," says Daniels, defending the comparison he draws in the film. "For over 200 years, they were slaughtered, they were murdered, and we were slaves. And we forget about it. We choose to talk about the atrocities that happened overseas, what other people have done . . ..
"Kids know more about the diary of Anne Frank than they do about the civil rights movement," he adds. "I hope The Butler changes that."
As for Haygood, who has an associate producer credit on the film, the liberties Daniels has taken are fine.
"The essence of the movie is Mr. Allen's life," he says. "When you look at the larger painting, Lee Daniels stays true to that painting of Mr. Allen's life.
"Now, Lee Daniels may have added certain colors here and there, because, look, you can't make . . . a four-hour movie. Things had to be tightened, compressed, condensed. But there was only one Mr. Allen, and I think the soul of the movie reflects his life very well."
Contact Steven Rea at 215-854-5629, email@example.com, or follow on Twitter @Steven_Rea. Read his blog, "On Movies Online," at www.inquirer.com/onmovies.