UNDER THE heading Better Late Than Never: "12 Years a Slave" finally gives America a definitive movie on its peculiar institution.

One could chastise Hollywood for being overdue, except that this movie isn't very Hollywood. British director Steve McQueen migrated to movies from the art world, and that's significant, because Hollywood, with its entertainment imperative ("Gone with the Wind"), has seemed to lack the language to properly explain the historic monstrosity that is slavery.

Watching the postmodern tomfoolery of last year's "Django Unchained" made you wonder whether the opportunity had passed. Did contemporary filmmakers have the moral imagination to engage the subject in a meaningful way?

"12 Years a Slave" answers, "Yes," resoundingly, drawing on the published, first-person narrative of Solomon Northrup (Chiwetel Ejiofor), an educated and prosperous free man living happily in Saratoga Springs, N.Y., until he's drugged, kidnapped and sold into slavery.

The facts of Northrup's life work enormously to the movie's advantage. In some ways, Northrup's dislocation becomes our own, and bridges the difficult gap between modern sensibility and the dreadful, period reality of slavery.

Northrup's status as a literate man also gives the movie its unique power and purpose. We see that he's an immediate and obvious threat to those who would own him. Not for his brawn, or his insurgent anger - muscle can be met with muscle, insurrection with guns.

What the slavers cannot abide, what exposes the flagrant hypocrisy of the institution, is Northrup's intellect. And it leaves Northrup exposed, too. Every time he opens his mouth, he lays bare the pretense that whites are superior to blacks.

Other captives sense it, fear it. On a slave ship heading south, Northrup is told that if he wants to live, he must never mention his free past, and especially never mention that he can read or write.

There is a small, vivid role for Chris Chalk as the man who gives Northrup this advice. The fellow then makes a quick but astonishing exit - it's a brilliant bit, one that places us in the historical moment and speaks to the folly of using conventional moral scales to measure people trapped inside this immoral system. (Ditto Alfre Woodard's later appearance as an owner's mistress.)

Northrup, though, learns the lesson of enforced ignorance the hard way. He cannot suppress who he is. So he's beaten by the trader who sells him (Paul Giamatti) and picked upon by the lunkheaded overseer (Paul Dano) who can't stand being outwitted by a black man. This prompts a confrontation that reveals the moral cowardice of the story's "benign" plantation owner (Benedict Cumberbatch).

All leads to Northrup's final ordeal at the hands of the dangerously unhinged plantation owner Epps (Michael Fassbender), for whom Northrup's destabilizing presence provokes a kind of madness. Scripture-quoting Epps is already fighting a raging internal war between his piety and his urges and actions, and Northrup pushes him to the edge.

It's here that the movie shows us in grisly detail the physical brutality of slavery. This is something of a specialty for McQueen, who made his reputation with "Hunger," an unblinking account of the mistreatment of IRA prisoners.

In "Slave," scenes of rape and rent flesh have gained a reputation for their rawness, but they do not dominate the movie (which is often almost inappropriately beautiful), and there is no point in engaging the subject without them.

And the most affecting scenes are of Northrup's self-diminishment. Through Ejiofor, we feel the tragedy of a man slowly pulling tight a tourniquet on his own intelligence, knowing that it's what he must do to survive, knowing also that merely to endure is not enough.

As he memorably says in the movie, he doesn't want to survive. He wants to live.

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