I realize there’s a danger in suggesting that McQueen is guilty of overkill: that it could be taken as an attempt to say “Slavery wasn’t as torturous as all that.” The hell it wasn’t. From a political and humanist standpoint, there are plenty of reasons to champion 12 Years a Slave. In his book, Northup directly addresses an audience that (mind-bogglingly) still exists — the one that insists that many slaves were happy in the bosoms of their masters. It should shame people with Confederate flags on their walls (“It’s about states’ rights!”) or Paula Deen types who harbor nostalgia for the elegance of the antebellum South. Epps reads Scripture to his slaves and lingers on a passage calling for them to be beaten “with many stripes” — proof that the Good Book can be employed in the service of manifold Evils. The movie nails all this, and it’s smashingly effective as melodrama. But McQueen’s directorial voice — cold, stark, deterministic — keeps it from attaining the kind of grace that marks the voice of a true film artist.