I shall start with the grubby & ungenerous part, which is that the documentary 13th isn't all that great as a movie per se. It's distractingly over-directed by Ava DuVernay, who shot all of her interviews from multiple angles and with editor Spencer Averick (credited alongside DuVernay as co-writer) cuts them together in a dizzying pattern of jumping back and forth, like something out of a damn celebrity infotainment program. She also relies, extensively, on onscreen text, of lyrics and certain key words from the interviews - the word "CRIMINAL" flashes up for a few frames literally every single time somebody says it throughout the movie - and between this and Selma, I wonder if it's fair to suggest that it's simply a weak spot for her.

So that's that. let us move beyond the grubby part, over to how 13th is an outright masterpiece of the political documentary form, the rare example of a political advocacy film essay which is so damn good at collecting information and marshaling it into a powerful argument that it feels completely essential despite its rather pedestrian cinematic technique. How damn good? This damn good: 13th is a project that attempts to trace out the entire history of systemic racism in the United States in all of 100 minutes, and it comes very close to succeeding completely. That should be absolutely impossible. It should take closer to 100 hours to cover that many centuries of exploitation - and to be fair, this is more of a broad-strokes overview than a detailed analysis that burrows into every last case study and historical movement. But a more perfect broad-strokes overview is difficult to imagine.

The film takes its title from the 13th Amendment to the U.S. Constitution, abolishing slavery and involuntary servitude, and doing so with one solitary wrinkle that DuVernay points out immediately the start of the film and continues to reinforce for all of the next hour and a half: "except as a punishment for crime". Those six words, in the eyes of 13th, are primarily responsible for the next 151 years (and counting) of life in America, during which time one system after the next was informally or formally instituted to make sure that African-American males were punished as criminals at a statistically inconceivably higher rate than other segments of the population. The argument is dead simple and, to this leftist, unimpeachable in its reasoning: from the cotton-dominated pre-war South to the monolithic private prison industry of the 21st Century, a large portion of the American economy has depended in some capacity or another on having lots of cheap, expendable bodies at the ready, and widespread racism meant that no bodies were held to be cheaper or more expendable than that of black men. The result has been decades of a hellish spiral in which African-Americans have been feared and despised as violent criminals, leading to more severe punishments and policing targeting them, which leads to an increasingly disproportionate number of African-Americans in prison, which reinforces the idea that they're violent criminals.

To flesh out this chain of reasoning against the last century and a half of American history, with a particular focus on the "law and order" fetish that kicked of oh-so-conveniently right around when the Civil Rights Act was signed into law, DuVernay has assembled an exceptional team of activists and historians, mostly black, some white: and while it's a pleasure to watch Angela Davis recount her stormy history and discourse in thoughtful tones on the sorry state of contemporary race relations, I don't think anything in 13th startled me as much as seeing no less a conservative icon that Newt Gingrich calmly agree that the sentencing guidelines for crack possession were blatantly unfair and racist, which somehow made me angrier than if he'd just dissembled. The whole thing is passionately argued, though maybe not so perfectly strong on the evidence that I can see it convincing anybody who flatly denied that the institutional racism of the prison system is even a thing; that being said, I don't think DuVernay is necessarily trying to make that argument, so much as providing a state of the union address, circa mid-2016.

The timing of course suggests that we should read the film in the light of the lately-concluded 2016 presidential election, and DuVernay allows us to do so, by showing a lengthy montage of Donald Trump on the campaign trail, saying viciously racist things and encouraging racism in others; but it's not a campaign promotion. Hillary Clinton shows up only twice, once to say the word "superpredators" as part of DuVernay's argument that Bill Clinton's 1994 crime bill was an unmitigated disaster in gutting black communities and leading to a massive spike in the prison population; once in the 2010s, accompanied by commentators suggesting that it's hard to assume that she'd actually be sorry for that crime bill if it wasn't politically advantageous for her to be so. The film doesn't let the Democrats off the hook much more than the Republicans (maybe less; the overwhelming feeling one gets is that the filmmakers passionately hate Bill Clinton, while finding Ronald Reagan merely loathsome), and is bluntly pessimistic that any developments in 2016 would be for the better. The last words spoken in the movie fall like a crack of doom, declaring in flat, unemotional terms that American racism and the exploitation of black bodies is going to proceed without much improvement for the foreseeable future.

By that point, DuVernay has assembled such an airtight case describing the shifting face of a consistent legacy of abuse and de facto slavery that I can't imagine anybody with any real intellectual honesty in them trying to argue that things are actually getting better. And that was before the election. It's a profoundly angry and hopeless film, but an enormously important one: 100 concise minutes explaining a complex sociological system with outstanding clarity and force, too intellectual to do anything so shabby as ask us to feel passively sad, when we can instead feel outraged. That's not, of course, a feeling that most people would deliberately seek out, but it is an outrageous world, and 13th, though it is surely better as journalism than it is a cinema, is essential viewing and probably the most important movie made in America in 2016.