Ava DuVernay’s new documentary about mass incarceration made me feel ashamed. After it ended, I thought about how much I’d gotten used to in just under two years of covering the criminal justice system for Slate—how thoroughly I have absorbed the unfathomable scale of the country’s prison crisis, and how normal it now seems to me that we tolerate a state of affairs that should be intolerable. I watched the movie for the first time with my wife, and was caught off guard about 20 minutes in, when a title card stating that the prison population had grown from 357,292 in 1970 to 513,900 10 years later made her audibly gasp. “Wait until we get to the ’80s and ’90s,” I said.

13th made me ashamed because it made me realize I’d stopped gasping. In its sweeping treatment of the history of American racism, the film brought me closer than I’ve ever been to understanding how it could be that so many people could have ever grown used to the moral catastrophes that were slavery and Jim Crow. How did they not wake up every morning, nauseated and panicked about what was happening? The same way people like me wake up in 2016 and take it as a given that there are 2.3 million people living in cages, a third of them black.

13th is named after the constitutional amendment that banned slavery—a putatively bright spot in the country’s history, except that, as the film underscores, it includes an exception that covers anyone who has been convicted of a crime. In that light, 13th is a perfectly ominous title for DuVernay’s project, the central argument of which is that, for hundreds of years now, the American justice system has been serving as a vehicle for racism and the political rhetoric that capitalizes on it. From the “convict leasing” of former slaves after 1865, to the criminalization of civil rights activism in the 1960s, to the craven politicking that used images of black criminality to win elections in the 1970s and ’80s, the story of how we got to our present moment is devastating in its coherence. Through interviews with a cast of experts that includes The New Jim Crow author Michelle Alexander, New Yorker writer Jelani Cobb, CNN commentator Van Jones, and Alabama-based justice advocate Bryan Stevenson, DuVernay’s film issues a warning: None of what’s happened has been an accident, and all of it has depended on the participation of rational people. Those of us who would prefer to think otherwise are forced to see the criminal justice system not as a well-intentioned instrument that has simply become overused, but as a weapon—one that has been aimed and fired with deliberateness and precision.

About halfway through the film, DuVernay and her subjects shift their focus from “how we got here” to “where we are,” and for a fairly long stretch, it feels like they can’t decide which travesty deserves to be dwelled on. In the span of about 40 minutes, the film throws its attention at the absurd cost of prison phone calls, the cynicism of the plea bargaining system, the sleaze of corporations that take advantage of prison labor, and the brazen unconstitutionality of cash bail. It’s during this dizzying tour of outrages that DuVernay starts developing what ends up being the film’s most disquieting idea: That for all the apparent energy that has surrounded criminal justice reform for the past several years, there is little reason to expect that the underlying logic of the existing system is at any risk of real disruption.

“They called the end of slavery ‘jubilee,’ ” says Jones, immediately after a bracing montage that juxtaposes archival footage of black civil rights activists being pushed around by whites with cellphone videos of violence directed at minority protesters at Donald Trump rallies. He continues: “We thought we were done then, and then you had 100 years of Jim Crow, terror, and lynching. … We get the bills passed to vote, and then they break out the handcuffs, label you a felon, [and] you can’t vote or get a job. So, we don’t know what the next iteration of this will be. But it will be.”

Listening to Jones, I was reminded of a time a few months into my tenure covering the criminal justice beat for Slate, when I wrote about an idea for reducing the prison population that turned out to be far more controversial than I expected. The idea, laid out on Vox, was simple enough: Instead of punishing so many people who have committed crimes by forcing them to spend years behind bars, let’s give some of them a chance to live out in the world, imposing strict rules on their conduct and using surveillance technology to monitor them. As long as these people know that breaking the rules will trigger swift and certain consequences, the argument went, they’ll be able to pay their debt to society under conditions that won’t upend their lives or expose them to the destructive horrors of the prison system.

It struck me as a promising proposal, especially after one of its proponents, then–University of California, Los Angeles professor Mark Kleiman, noted that it could be paid for with money that would otherwise be spent providing prisoners with room and board. But when I called some prominent criminal justice reform advocates and asked them what they thought of Kleiman’s vision, I was taken aback by the amount of opposition I heard. Glenn Martin, the head of an organization called JustLeadershipUSA and a prominent voice in 13th, called it a “well-intentioned … system of oppression,” and warned that it would widen the net of people whose freedom has been stolen by the state. Marie Gottschalk, author of the 2014 book Caught, called it “chilling” and noted that “some of the worst bars are the ones that people acutely experience but are invisible to the rest of the world.” Others echoed these sentiments, saying that the system Kleiman had in mind was nothing more than a technocratic redeployment of the very same pro-carceral impulses that caused the number of Americans in jail and prison to surge from 350,000 in 1970 to more than 2 million in 2015.

I was skeptical of these arguments, and I nodded in agreement when Kleiman said to me, by way of rebuttal, “The proposition here is not that we should sentence people to this. The proposition is that we should take people who are currently in prison and let them out.” The debate revealed for me an important fault line in the criminal justice reform movement—one that separated optimistic pragmatists like Kleiman from radicals who demanded nothing less than revolution. In the weeks and months that followed, I remember rolling my eyes whenever I heard activists and academics in the latter camp make the point that incremental reforms of the sort Kleiman had in mind—tweaks to the system that they saw as reinforcing the basic structure of the carceral state instead of challenging it at its foundation—were the enemy of real progress.

This is where I should say that watching 13th changed my mind entirely—that after being confronted with the depth of the rot under our feet, I now see the folly of Kleiman-style incrementalism and am ready to declare myself a full-bore prison abolitionist. But that is not really true. As convincing as the film is in tracing the national pathology that connects slavery and mass incarceration, as effective as it is in forcing its viewers to reckon with the cruelty of the prison system, it left me, in the end, with the queasy guilt of a helpless bystander—someone who doesn’t want to tolerate the imprisonment of 2 million people but has no idea what that means in practice.

What does rising to the occasion of this profound and urgent problem look like? What policies or reforms should a person support if she or he watches 13th and finds himself, as I did, paralyzed with awareness? While turning these questions over in my head, I came across a recent interview with Michelle Alexander, a radical leader in the world of criminal justice reform and as close to a star as 13th can be said to have. In the interview, Alexander expressed a point of view that sums up why I think DuVernay’s documentary might turn out to be important:

I don’t view mass incarceration as just a problem of politics or policy, I view it as a profound moral and spiritual crisis as well. I think that racial justice in this country will remain a distant dream as long as we think that it can be achieved simply through rational policy discussions. If we take a purely technocratic approach to these issues and strip them of their moral and spiritual dimensions, I think we’ll just keep tinkering and tinkering and fail to realize that all of these issues really have more to do with who we are individually and collectively, and what we believe we owe one another, and how we ought to treat one another as human beings. These are philosophical questions, moral questions, theological questions, as much as they are questions about the costs and benefits of using one system of punishment or policing practice over another.

For people who have devoted their lives to fighting for political reform, this might read as a rejection of all the hard, slow, boring work that goes into making change happen. Part of me is tempted to read it that way, too. But maybe the point is that for all that work to matter, those of us on the sidelines—the bystanders who decide, in aggregate, what can be tolerated—must have an urgent, vivid understanding of what the people we’re counting on to achieve progress are up against. That’s what a film like 13th is for: It makes us gasp and not stop gasping.