On demand: "13TH"

Early reviews suggested Ava duVernay's documentary follow-up to her much-admired breakthrough feature Selma was going under the title The 13th. Now that it's reached its ultimate home on Netflix, we can see that that title appears on screen as the far starker 13TH - a reference to that crucial amendment in the Constitution that defines who, in the quote-unquote land of the free, actually gets to live free. duVernay's using her newly bestowed stateswoman role to critical ends here, parlaying the success of her previous project into an extended inquiry into whether or not the Civil Rights Act with which Selma finished wasn't, in fact, something of a false dawn. The stats are damning: here's a film that questions how, at the tail end of the Obama administration, America arrived at a situation where a country boasting five percent of the world's population could have ended up jailing a quarter of the entire planet's prisoners, the majority of those black.

The opening stages thus function as a primer in race relations since the Civil War, whisking us through the lowlights of The Birth of a Nation - that blockbusting exercise in racism that enshrined a certain idea of the African-American in white consciousness - to arrive at the Klan, segregation and that late Sixties moment where the panicked powers-that-be reacted to the growing turmoil on the streets by inscribing suspicion, paranoia and outright prejudice into law. duVernay and her co-writer Spencer Averick show how - like capitalism - the phenomenon of mass incarceration only accelerated under the ultra-conservative Nixon and Reagan administrations: from 350,000 prisoners in 1970 to double that by the mid-1980s, reaching 2.13m by 2014. That figure surely wouldn't have been allowed to creep that high had the policy been a lossmaker; clearly, at some point, someone realised it was possible to make big bucks from keeping people behind bars. (The film's Netflix stablemate Orange is the New Black has dramatised this very issue over recent seasons.)

To any British viewers wondering what this problem has to do with them, I'd first say a) how very parochial of you, and then b) as is generally the way with culture and policy alike, what starts in the US is often carried via geo-economic current to the UK. (Seek out this summer's The Hard Stop for further information.) In 2016 of all years, we should all feel a chill of recognition entering the room during the segment that outlines how Nixon realised he could reach out to poor white voters with openly racist imagery and rhetoric; as several survivors of that moment attest, when you create a context in which one group of people is afraid, another group of people often wind up in the garbage pail, or on the bonfire. Some of these tactics clearly aren't going away - a lamentable situation only underlined when the film begins to explicitly address the contenders in the current US Presidential race.

Inevitably, Donald Trump's heavily harrumphed thoughts on the Central Park Five case are called back into question, yet duVernay and Averick also call out Hillary for using the loaded term "super-predator" in an early 90s speech on crime, and they venture that her husband only reached the White House after deploying tougher rhetoric than his opponent George H. W. Bush in a bid to win over conservatively minded floating voters. Bill's "three strikes" policy is cited as one of the main reasons the number under discussion has skyrocketed since the millennium, jailing so many (without the possibility of parole) for relatively minor infractions. (It's a sign of just what a topsy-turvy year this has been politically that the Caucasian senator who emerges with the most credit from duVernay's interviews is the veteran Newt Gingrich, who admits it was racist for Congress to push for punitive measures against the - predominantly black - users of crack, when those of oh-so-white cocaine, doubtless including some key Washington staffers, were being let off with warnings.)

The result is one of those umbrella docs that usefully rounds up and digests the themes and arguments of a decade's worth of engaged non-fiction - films like The Black Power Mixtape 1967-75, The Black Panthers: Vanguard of the Revolution and The House I Live In - while seeking out pockets of new and valuable material. duVernay draws a very persuasive line between Jim Crow-era lynchings and the recent spate of shootings involving unarmed young black men - where a different weapon has been deployed to bring about the same oppression, written into the very fabric of American life as business as usual - and she draws out a series of revelations on the mysterious group known as ALEC (the American Legislative Executive Committee), a cabal of corporate interests convened to write overextended congressmen's bills for them, including that which engendered the controversial Stand Your Ground loophole by which George Zimmerman was exonerated for killing Trayvon Martin.

All of it packs a punch, yet much of 13TH's potency lies in the film's stitching: in Averick's own hands, this is a most sharply cut documentary, weighing point against counterpoint in mini debates of a rare clarity and perspicacity, and working recent footage of the Democratic primary debates and footage of black protestors being shoved around at Trump rallies into a 100-minute single-sit briefing. duVernay may be responsible for the additional layer of pop-cultural savvy: the lyrics of songs by key black voices, from Paul Robeson to Public Enemy, provide their own damning commentary on a history we see repeating itself. Will 13TH have any impact beyond the sitting room? Well, who knows: at this point in 2016, you fear anything might happen. Still, this hellyear would have to outdo itself if a film this combative yet accessible and eloquent didn't resonate in some way among voters and legislators alike. To paraphrase a lament raised around the time of Dr. King, a change is going to have to come - the question 13TH leaves us facing is when, and what form it will take.

13TH is now streaming on Netflix.