Quentin Tarantino has made a career of corkscrewed portrayals of race. Why is he so squeamish about sex?

The release of Quentin Tarantino's Django Unchained has kicked off the gnarliest round yet of a debate that never gets old. What are we supposed to make of his alternately frisky and convoluted relationship to African American culture? Crude exploiter, extravagantly repurposing fabulator, sly prankster tweaking everybody else's racial hangups and categories—he wouldn't be our Quentin if he didn't give us plenty of ammo for all three takes. But if you go along with Stuffyville's abiding notion that he's some sort of post-everything pop nihilist and that's all there is to it, the reason Django is the most problematic movie of his never dull career may surprise you. Leaving aside the lardy script and self-indulgent length, this sucker's larger failure is its sentimentality.

Even though Tarantino's cinematic idiom of choice is barbaric shlock transfigured by wit and self-conscious genius, underneath it, he's as eager as a 1970 Swarthmore grad meeting her first Black Panther to let African Americans know he digs their historical struggle. And because the real hangups on ample display in his filmography are less racial than sexual—not that he hasn't made gleeful hay out of conflating the two—what he leaves out of Django Unchained may reveal more than all the gaudy stuff he's happy to shove in our faces.

I speak as a Tarantino admirer who truly hoped he'd pull Django off. His anything-goes pulp sensibility has a way of producing unruly insights I prefer to respectable bromides. How often that almost happens here makes Django frustrating as well as tedious, particularly after its very promising first act. The movie can't be faulted for lack of ambition: Dramatized via Jamie Foxx as an ex-slave who teams up on the eve of the Civil War with bounty hunter Christoph Waltz (the Oscar-winning villain of Tarantino's infinitely better Inglourious Basterds) to rescue Foxx's wife from decadent plantation owner Leonardo di Caprio, who's abetted by a bunch of predictably Colgate-challenged rednecks—that Waltz's character is a dentist turned anti-racist avenger is the subtlest joke here by miles—Quentin on Slavery was pretty much the only way of upping the boldness ante after Inglourious Basterds gave us Quentin on the Holocaust.

Still, let us note that Steven Spielberg, Tarantino's opposite in about every way, obeyed the same trajectory by following up Schindler's List with Amistad. Behind them both is the all-thumbs, Casper-like ghost of liberal '60s producer-director Stanley Kramer, who followed up his sententious Judgment at Nuremberg and Ship of Fools—trust me, Nazism's reputation has never recovered—with Guess Who's Coming To Dinner?. Then there's that cutup Mel Brooks, who followed The Producers with Blazing Saddles. The Auschwitz-to-racism pattern is pretty uncanny.

What differentiates Tarantino from the others is that a white boy's impudent and corkscrewed take on African-Americaness has been part of his act from the start. In Pulp Fiction, most famously, he indulged his superspade fantasies by casting Samuel L. Jackson as the world's studliest hit man and Ving Rhames, by way of unconscious payback, as the victim of Tarantino's idea of the ultimate indignity: buggery. Next came the blaxploitation tribute Jackie Brown, crystallizing irreverence as reverence by other means. Despite my teenage fascination with Norman Mailer's tellingly bonkers midcentury essay, "The White Negro," I hardly thought I'd end up citing it as a relevant text in connection with any filmmaker's work in 2012.

Jackson, as it happens, turns up in Django Unchained as DiCaprio's monstrous, ossified black butler, "Stephen." That's as in Stepin Fetchit, folks, and I can remember when sussing out Tarantino's references was more like doing the Times's Sunday crossword puzzle than one in an in-flight magazine. The concept of a slave who's internalized the system to the point of being more royalist than the king is Django's most provocative notion, but in practice it's just another excuse to hear Jackson say "Motherfucker" in unexpected contexts. At this late date, I doubt we need more proof that nobody does it better.

True, not many American movies, worthy or otherwise, have dramatized the horrors of slavery at all. Even Spike Lee, whose sight-unseen attacks on Django sounded suspiciously like a way of protecting his increasingly dubious copyright on all things African-American, has steered clear in his own work of confronting that abyss. To my eyes, however, the real problem isn't that Tarantino is a white dude appropriating black experience to his own Grand Guignol purposes; it's that he's as squeamish about sex as he is unabashed about violence. The plot's entire motor is Django's sexual rage that his wife has been forced into concubinage. But—one flash of sickening public humiliation aside—we aren't shown her being violated, or even given any indication that she has been. She just seems to be hanging around "Candyland" (the DiCaprio character's plantation) in a state of apprehension about what might happen to her once her laggardly masters catch on she's available. This is, of course, another form of sentimentality, and a ludicrously decorous one coming from Mr. Pulp Insolence himself.

Since I'm sure I'll be misunderstood, let me be clear: I'm hardly complaining that my craving for prurient jollies went unslaked. I regret Tarantino's missed opportunity to genuinely disturb and appall audiences, not turn them on. For both its female victims and the black men with no recourse to stop or even protest the practice, sanctioned master-on-chattel rape had to have been slavery at its most nightmarish; Tarantino's story is premised on avenging it. Yet he can't bring himself to depict it in the first place, an omission that does a lot to keep Django Unchained hollow and cartoonish at its very core. Emotionally, this florid, intermittently arresting, but only superficially outrageous movie makes no sense unless we see DiCaprio having his way with Kerry Washington, not just giving baroquely hateful speeches about black inferiority. Even though the conventional outcry against Django in some quarters is sure to be that Tarantino has gone too far, the movie's best-kept secret is that he didn't go far enough.