Lee Daniels’ The Butler puts its ambitions on display with all the obvious grandness of a state dinner at The White House. At its most basic, it’s the story of a dignified black man who rises from humble beginnings to become a butler at that White House, serving at the pleasure of seven U.S. presidents. But really, it’s the story of pretty much every significant thing that’s happened to African-Americans in the 20th and 21st centuries.

The remarkable thing is that even with those bold aspirations, the film sometimes works. Its two leads are a big help in this regard. As Cecil Gaines, the young man who leaves his life as a so-called “house nigger” on a Georgia cotton farm and eventually works his way up to serving tea trays to JFK, Forest Whitaker is wonderfully restrained. As Cecil’s wife Gloria, Oprah Winfrey mostly overcomes her own Oprah-ness, particularly as she ages into an old woman whose voice has weakened but whose soul is still all feisty spunk. Meanwhile, Lee Daniels—the director whose name appears in the film’s title and who most recently tossed all restraint out the window to make the swampy, sordid The Paperboy—wisely makes sure the audience never gets too comfortable watching a black man in a subservient role.

In one particularly moving sequence, Daniels toggles between Cecil, as he sets out the fine commander-in-chief china for a formal White House meal, and his son, Louis (David Oyelowo), as he’s berated for not sitting in the colored section at a lunch counter down South during a Civil Rights–era protest. It’s a scene that basically summarizes the whole movie, emphasizing how one generation of African-Americans broke down barriers quietly, by working within a system controlled by whites, and another blasted away those barriers, with rage sometimes barely contained. The problem is that this dichotomy, as well as the nature of the relationships Cecil develops with the occupants of 1600 Pennsylvania Avenue, increasingly becomes too preposterous to be believed. Lee Daniels’ The Butler eventually starts to drown in a soup of Forrest Gumpiness.

The movie is based on a real man, Eugene Allen, who really did serve as a White House butler for many decades and, as explained in a series of stories by the Washington Post’s Wil Haygood that inspired The Butler, really did become a witness to history. (Disclosure: I previously worked at the Washington Post with Haygood.) But did Mr. Allen, like Cecil, really stand alone in the same room with Jackie Kennedy (Minka Kelly), as she wept with fresh blood on her Chanel suit shortly after the assassination of husband John F. Kennedy? Did Richard Nixon (John Cusack, with a hooked, prosthetic nose) really share a late-night drunken confession with Mr. Allen, as he does here with Cecil, in which he refuses to resign in the wake of the Watergate scandal? Did Ronald Reagan (an overly serious Alan Rickman, another in the parade of too-recognizable actors playing ex-presidents) really say the following to Mr. Allen, as he does to Cecil during the debate over his attitude toward South African apartheid: “This whole Civil Rights issue: Sometimes I fear I’m on the wrong side of it”?

It seems unlikely, just as unlikely as the idea that Cecil has a son who simultaneously finds himself on freedom rides just before the buses burn, or in Martin Luther King Jr.’s presence shortly before he gets shot in Memphis, or in the Black Panthers at a time when Nixon is advocating, in Cecil’s presence, that such revolutionaries be squashed like bugs. (For the record, Allen had one son named Charlie, who is represented in the movie, but there was no Louis in his life.) Daniels and screenwriter Danny Strong seem so intent on intertwining their narrative with history that they lose their grip on the credibility established in those early scenes, when Cecil happily shows up at the White House with his freshly pressed tuxedo while, at home, his son casts a skeptical side-eye at his father’s pride. One wonders if The Butler would have been a stronger, tighter movie if it had laser-beamed its focus on the 1950s and 1960s, then fast-forwarded directly to the election of Barack Obama that—no spoiler alert necessary—serves as the obvious bookend for the tale of a black man working in the White House.

Unfortunately, we’ll never know. What we do know is that, as well-intentioned and occasionally effective as Lee Daniels’ The Butler is, it can’t match the pieces that Haygood wrote. Those stories tell the facts of a real man’s life in a way that makes the reader feel their weight and significance. The movie version ultimately tries too hard to convey that same kind of weight, but relies too heavily on contrived fiction to pull it off. —Jen Chaney