The question to be answered about Steve McQueen’s 12 Years a Slave is this: whether or not it expresses a truth about chattel slavery as practiced in the American South before 1865 — and let us stipulate that it does — does it express the truth? In everything I have read about it, the assumption seems to be that it leaves nothing more to be said on the subject. The movie “vividly conveys the realities of life within the peculiar institution” writes Annette Gordon-Reed in the New Yorker. Eric Foner, like Ms. Gordon-Reed a credentialed historian, tells an interviewer for the New York Times that he thinks “this movie is much more real, to choose a word like that, than most of the history you see in the cinema. It gets you into the real world of slavery.