Watching 13th, the new documentary from Ava DuVernay (Selma), is like standing in the way of a fire hose that’s being slowly cranked up to full blast. You take a little more pressure every moment, until it gets to be staggering, a little bruising.

Rating 4

Then you turn around and realize that the hose is aimed at a blazing fire. And as you gaze at its destructive heat, the pressure and discomfort pales by contrast.

Vital, searing, and engaging, 13th (in theaters and on Netflix on October 7) is a primer on the historical context and moral urgency behind a lot of today’s most pressing public issues, from mass incarceration and the war on drugs to police brutality and private prisons, along with an exploration of what’s behind Black Lives Matter. It’s the movie to recommend to your loved one who is worried the media is "race baiting." And watch it yourself, especially if you’re still trying to grasp how we got to where we are today.

The movie is named for the 13th Amendment, ratified in 1865, which abolished slavery but contained a loophole: "Neither slavery nor involuntary servitude, except as a punishment for crime whereof the party shall have been duly convicted, shall exist within the United States, or any place subject to their jurisdiction." In other words, slavery isn’t permitted — but only for people who aren’t convicted of a crime. Once you’re convicted, all bets are off.

That clause depends on a just court system in which every person accused of a crime is treated fairly and equitably — which, in turn, depends on a policing system that accuses people in the same manner, with no consideration for their race, class, or gender.

Yet none of those things are true, as the statistics bear out — and many on the left and right differ on causes but agree there’s a big problem. (Keep in mind that convicted felons aren't permitted to vote.) 13th makes the strong case that this sort of prejudice, and even hatred, is baked into the American system, and that we have to reckon with the legacy of centuries before we can really start to think about "justice for all."

13th is activist filmmaking at its most effective

The documentary is a compelling whirlwind tour through America’s long history of racism and, perhaps more importantly, America’s long history of denying its racism. It scored the prestigious opening-night slot at the New York Film Festival on September 30, becoming the first nonfiction film to do so in the festival’s 54 years, and DuVernay the first black woman director to do so as well.

That it’s releasing to Netflix the same day as its theatrical release is a calculated move. Answering questions after the festival’s press screening, DuVernay jovially thanked the revenue Netflix pulled in from shows like Luke Cage and Stranger Things for helping provide the budget needed for a project like this.

But then she noted that releasing the film on Netflix right away helps circumvent the nation’s "cinema segregation." As many noted last summer, one of the few places you couldn’t watch Straight Outta Compton was Compton itself, because there are no movie theaters there — in low-income areas, theaters simply don’t open, and those places are disproportionately nonwhite. If there is a cinema in such an area, it’s likely to play only a few big studio films picked by marketers.

"Black and brown people should have more than a steady diet of Marvel films — no disrespect to the Marvel films," DuVernay said. (You couldn’t see her Oscar-nominated Selma in Selma, Alabama, either.)

13th traces a damning line from slavery and abolition to today’s injustices, noting in the film’s opening moments that though the US population accounts for less than 5 percent of the world’s population, nearly one in four people incarcerated worldwide are in America’s prisons.

A host of experts and activists (and a handful of naysayers) appear in the film, alongside charts, images, archival footage, and even song lyrics — all mustering history and statistics to bear witness to the evidence. Some of them are to be expected — Michelle Alexander, author of the best-selling The New Jim Crow, activist and commentator Van Jones, the New Yorker’s Jelani Cobb, historian and critic Henry Louis Gates Jr., controversial activist and scholar Angela Davis, former Newark mayor and New Jersey Sen. Cory Booker, and many more. (The film steers mercifully clear of inexperienced celebrity activists.)

Others are a bit more startling. Surely the most surprising is former Speaker of the House Newt Gingrich, who avers that no white person can understand what it is to be a black person in America and voices regret for the policy mistakes he and others made in the past few decades that have only contributed to the spike and its problems. Presidents and presidential candidates on left and right don’t get a pass either: Both Clintons and Donald Trump come in for judgment, just through video clips of their own speeches and assertions (though Trump's continuing refusal to back down on the Central Park Five case is especially troubling).

Throughout 13th, black people assert again and again that their goal is to be seen as full, complex humans—to be rehumanized, as several put it, in the face of centuries of dehumanization. Things have changed, in many respects. But the film shows that troubling trends in incarceration (and particularly in the privatization of the prison system, which is more complicated than the headlines) continue to strip away citizens’ dignity and humanity.

13th is about how images have shaped, and continue to shape, our national imagination

These statistics and arguments have been presented before, but rarely with such cinematic lucidity. DuVernay and her co-writer Spencer Averick (who also edited the film) rely on the usual activist documentary format to build their case — interviews and statistics, no narration — but their sense of the film as a movie and not just a nightly news segment is what makes it engaging and even enraging. Films aren’t just vehicles for delivering information: They involve music, editing, and, most importantly, images.

The movie's arguments and implications for policy are a matter of life and death, and yet it’s the images that stayed with me after 13th.

I’d seen some of the more iconic and disquieting pictures, like the image of Gordon, the slave who’d been whipped so many times that his back, when photographed, was a latticework of scar tissue. In July 1863, the photographs of Gordon were published in Harper’s Weekly, and many who saw it — including free black men — joined the Union Army as a result. You can be told about the horrors of slavery all you want, but a picture is worth not just a thousand words but, sometimes, a whole library.

As a filmmaker, DuVernay knows this. And she puts it to use. Talking-head interviews are great, and her subjects are compelling, but what really lingers is the copious archival photography and video footage that she leans on to make the case. It’s easy to dismiss pundits, but it’s much harder to dismiss what you see with your own eyes: black people being assaulted and brutalized, deeply racist images from light entertainment and landmark cinema like D.W. Griffith’s The Birth of a Nation, declarations that make most contemporary Americans cringe, pictures and videos from the civil rights movement, and much, much more.

Watching, it’s hard to miss the point: If racism depends on skin color first and foremost, then images are the most powerful ways to shape public opinion both toward and away from prejudice. So the responsibility for confronting the biases and outright lies that images can powerfully perpetrate lies with the image makers, especially when the portrayals simply do not line up with actual facts.

And, in large part, the responsibility also lies with the image watchers.

DuVernay draws a strong line between racism's past and its present

Late in the film, DuVernay — with permission from the families — cuts in videos now familiar to many of us, of the unarmed black men whose deaths in police-related incidents have gripped the nation. But by the end of the film, the familiarity is gone: The images have taken on new weight. The audience is being asked to bear witness.

That’s the most heartbreaking part of the film, but it isn’t even the most disturbing. Near the end, DuVernay reintroduces an archival video of a black man being shoved by a group of white men as he tries to cross the street. As they knock his hat off and continue to shove him down the sidewalk, along with other monochrome images of black people being assaulted we hear audio from Trump rallies in which he reminisces about the "good old days" when protesters would be treated "very, very rough" or even carried "out on a stretcher." That’s intercut with images of people being shoved and physically assaulted at Trump rallies. It’s chilling. "I can’t watch that without tearing up," DuVernay said.

13th has more pressing concerns than representation in Hollywood and #OscarsSoWhite; it’s most interested in policy and institutions. But it’s also worth noting that since The Birth of a Nation, released in 1915, and extending much further back, visual art and entertainment, especially visually driven entertainment, has had a hand in perpetuating stereotypes that shape white viewers’ imaginations about nonwhite people so deeply that the biases are hard to recognize.

And if entertainment has a responsibility to represent people in a more just way, it’s just as true that audiences bear responsibility to seek out and even clamor for better art. When more voices are represented and heard, when more images are seen and internalized, that’s a win for everyone.

The film ends with images of "black joy," as DuVernay put it — photographs of black people and families celebrating and living their lives. It’s a purposeful choice, and a humanizing one.

"Black trauma is not our life," DuVernay explained. "We are survivors."