Nelson Mandela's basic story is known to most Americans, but the details, as dramatized in "Mandela: Long Walk to Freedom," will be a revelation for many. Even those familiar with the history will be impressed and moved to see these events as Mandela experienced them, before the Nobel Prize and universal adulation re-cast the past in a glow of inevitability.
What comes through in Idris Elba's performance is a leader of enormous emotional strength. Here's a man in his mid-40s, sentenced to life in prison on Robben Island, where he is called "boy," forced to wear short pants and work at hard manual labor.
The international community is years away from caring. Clearly, only someone with a capacity to take the long view could find a shred of hope in this situation. Only someone with a regal sense of self could keep from breaking. And only someone with a preternatural mental discipline resist falling into an all-consuming vat of resentment.
"Mandela: Long Walk to Freedom" overcomes the two main challenges that any Mandela drama must face. The first is the obvious one, to make an audience understand and feel exactly what made Mandela remarkable.
The second is more subtle. It's a dramatic challenge, to maintain movement and velocity in a story in which the central character spends 27 years in prison. That it's possible to watch "Mandela" and not realize that difficulty is a measure of its success.
The film tells Mandela's story from his early years, when he seemed poised for a comfortable life as a successful lawyer, albeit a life circumscribed by apartheid.
A certain temperamental inability to withstand or witness injustice draws him into revolutionary activity, where he rises to become the leader of the African National Congress. In these years, we see an angrier Mandela, who is also a womanizer. By the time he is imprisoned, he is already married to his second wife, Winnie, who is 18 years his junior.
Elba's performance is commanding and physically meticulous. As he ages throughout the film, he takes on the stiff gracefulness of the elderly Mandela, so familiar to us from news footage.
At the same time, Elba cannot escape the difficulty that comes with playing any fantastically famous individual. And so, there's rarely a moment watching him that we are not consciously aware of his effort to talk and move like another person. This isn't terrible, and with as distinctive an individual as Mandela it was probably inevitable, and yet it's notable all the same.
With the lesser-known Winnie Mandela, Naomie Harris has an easier time, and she emerges as a fierce and fascinating figure. She starts off as a young idealist, but government harassment and prison stretches radicalize her. There's a scene in which she leaves prison and tells the press and supporters that she is no longer afraid of anything. Harris has a look in her eye -- you believe her.
The dynamic between Nelson and Winnie is complicated, with much being said between the lines. When Harris, as Winnie, looks at the white-haired Mandela, newly free, you know that she thinks she's stronger than he is, knows more than he does and really isn't all that interested in this elderly version of the strapping man she married decades before. Not a word is spoken, but it's in Harris's face, and suddenly no explanation is required as to why they soon divorced.
At times, "Mandela: Long Walk to Freedom" lurches from event to event, in the way that movies do when filmmakers are covering lots of history. This results in some moments of awkwardness, but they are a small price to pay, when the overall effect is enlightening and inspiring.
Mick LaSalle is The San Francisco Chronicle's movie critic.