There’s a “Standard Story” that many Americans, particularly on the left, believe about mass incarceration: During the 1970s and ’80s, the federal government dramatically escalated its war on drugs. This alone led to millions of people getting locked up for fairly low-level drug offenses, causing the US prison population to spike. This new prison population is predominantly black, leading to massive racial disparities in the criminal justice system. And all of this happened, not coincidentally, right after the civil rights movement — showing the rise in incarceration was a ploy to oppress black Americans just after they made huge gains.

But in a new book, Locked In: The True Causes of Mass Incarceration and How to Achieve Real Reform, Fordham University criminal justice expert John Pfaff offers a trove of evidence that this narrative is by and large wrong or, at the very least, misses much of the real story.

The “Standard Story” of mass incarceration, as Pfaff calls it, was largely popularized by a 2010 book, The New Jim Crow: Mass Incarceration in the Age of Colorblindness by Michelle Alexander. Pfaff goes through many facts and statistics to show that this Standard Story gets a lot wrong about the causes and realities of mass incarceration, from the types of crime that people are locked up for (in reality, largely violent offenses) to the areas in which reform is truly needed (with a focus on state and local, not federal, reform).

“The core failing of the Standard Story is that it consistently puts the spotlight on statistics and events that are shocking but, in the grand scheme of things, not truly important for solving the problems we face,” he writes. “As a result, it gives too little attention to the more mundane-sounding yet far more influential causes of prison growth.”

The story that Pfaff carefully describes is different from the standard narrative: It’s not drug offenses that are driving mass incarceration, but violent ones. It’s not the federal government that’s behind mass incarceration, but a whole host of prison systems down to the local and state level. It’s not solely police and lawmakers leading to more incarceration and lengthy prison sentences, but prosecutors who are by and large out of the political spotlight.

The book dampens much of the excitement around the progress we’ve seen in the past few years. Starting in 2010, the incarceration rate began to fall in the US for the first time in decades. But the drop has been slight, driven mostly by changes to sentencing laws for low-level drug and property crimes.

And based on Pfaff’s work, this drop won’t continue — at least in a dramatic fashion — as long as reformers and the public remain focused on a Standard Story that’s almost entirely about the federal war on drugs.

“Simply stopping the rise in incarceration has been a huge accomplishment,” Pfaff notes. “If the goal is real decarceration, however, it is time to shift focus to the much broader, much more confounding issues that keep us locked in to our current predicament.”

To this end, Pfaff agrees that, for example, we should strive to get low-level drug offenders out of prison. He just says it’s not enough — that the real issue is much bigger.

It’s an uncomfortable read, not least because it suggests America will have to make some very tough choices if it wants to seriously cut the incarceration rate: Are we really okay with locking up fewer violent offenders? Does the country really have the ability to sustain a focus on local and state politics to ensure that the real sources of mass incarceration come down? If America does stumble upon a new crime wave or drug crisis, will all the work that’s already been done be pulled back as politicians resurrect “tough on crime” rhetoric (like President Donald Trump has)?

All of this is a reason for reformers to be pessimistic about their ability to undo mass incarceration. The bright spot, if there is one, is that work like Pfaff’s can help expose the real problems in the system, leading to more sustainable solutions.

Drug offenders make up a small portion of the US prison population

No misconception wraps the Standard Story more than the belief that mass incarceration was caused by the war on drugs. This was widely popularized by Alexander’s The New Jim Crow. That book argues that, facing the success of the civil rights movement, racist lawmakers shifted to another regime to try to control black Americans: the criminal justice system. So the federal government launched the war on drugs, locking up black people for low-level drug offenses and driving incarceration rates in the US to astronomical highs.

“The impact of the drug war has been astounding. In less than thirty years, the U.S. penal population exploded from around 300,000 to more than 2 million, with drug convictions accounting for the majority of the increase,” Alexander writes. She later claims that “the uncomfortable reality is that arrests and convictions for drug offenses — not violent crime — have propelled mass incarceration.”

Pfaff demonstrates that this central claim of the Standard Story is wrong. “In reality, only about 16 percent of state prisoners are serving time on drug charges — and very few of them, perhaps only around 5 or 6 percent of that group, are both low level and nonviolent,” he writes. “At the same time, more than half of all people in state prisons have been convicted of a violent crime.”

By the numbers, Pfaff is correct: The latest data by the US Bureau of Justice Statistics shows that in state prisons, where about 87 percent of US inmates are held, nearly 53 percent are in for violent offenses (such as murder, manslaughter, robbery, assault, and rape), while only about 16 percent, as Pfaff said, are in for drug offenses.

These figures are at best a minimum for the number of violent offenders in prison. It’s not rare for violent offenders to plea down their charges to nonviolent crimes; this lets offenders get a lower sentence, and it lets prosecutors and judges skip a costly trial. So at least some of the supposedly nonviolent offenders have likely committed violent crimes.

This context is crucial to understanding why mass incarceration happened: It really was a reaction to a massive violent crime wave. From the 1970s to ’90s, violent crime rose dramatically across the US — and lawmakers responded, in what Pfaff characterizes as an overreaction, with mass incarceration.

That doesn’t rule out the role of racism. One reason that policymakers overreacted to the crime wave, Pfaff acknowledges, is likely prejudice, given that “our durable history of racism may make rising crime seem more frightening to white voters than it is to Europeans [who didn’t react to their own crime waves with similar bouts of incarceration], or at least it may ensure greater rewards (or fewer risks) for politicians who crack down on poor minority communities.”

Still, the statistics indicate that violent crime played a huge role in mass incarceration. It wasn’t just — or even mostly — the war on drugs. “Until we accept that meaningful prison reform means changing how we punish violent crimes, true reform will not be possible,” Pfaff writes.

Yet the opposite has happened. Over the past few years, local and state lawmakers have enacted criminal justice reforms. But these efforts almost always focus on low-level drug and property offenses. In some cases, lawmakers and reformers will argue that low-level offenders need to be kept out of prison so more violent offenders can be locked up — a framework that could lead to more incarceration, not less. (Consider the common line that we need to “focus expensive prison beds on those who deserve them the most.”)

Pfaff cites Georgia, often celebrated as a success story in criminal justice reform, as one example: “Georgia’s lauded 2011 reforms have cut prison populations, but hidden in that decline is a rise in the absolute number of people serving time for violent crimes — people whose sentences tend to be longer, and whose rising imprisonment may, in the long run, undo the short-run declines.”

This won’t work, Pfaff argues: “Freeing every single person who is in a state prison on a drug charge would only cut state prison populations back to where they were in 1996-1997, well into the ‘mass incarceration’ period. That’s not to say we shouldn’t think about releasing a lot of those who are in prison for these sorts of crimes, but we need to be realistic about what doing so would accomplish more broadly.”

One caveat to this part of Pfaff’s argument is the churn of the prison population. While the majority of people in state prison at a single point in time are in for violent crimes, many more people are admitted to prison for drug and property offenses than for violent ones. But the lower-level offenders end up serving much shorter sentences, so they don’t add as much to the total prison population at any given point in time as violent offenders do. This was demonstrated in a 2015 analysis by Jonathan Rothwell for Brookings, where he charted the “stock” and “flow” of prisons and how they differ based on offense:

So while reducing the number of violent offenders in prison is needed to undo mass incarceration (as measured by the total prison population), cutting back on drug and property offenders would still do a lot to lower the total amount of people exposed to the criminal justice system.

The big criminal justice story is local, not federal

Another fundamental problem with how the Standard Story approaches mass incarceration is the narrative poses the greater rates of imprisonment as the result of one system, working to perpetuate mass incarceration as a singular response to civil rights gains. As Alexander writes in The New Jim Crow, “We have not ended racial caste in America; we have merely redesigned it.”

The reality is that there are many systems at play — more than 3,100, representing every county and county equivalent in America. As Pfaff writes, “[T]he term ‘criminal justice system’ is a misnomer; criminal justice is, at best, a set of systems, and at worst it is a swirling mess of somewhat antagonistic agencies.”

Despite the perennial focus on the federal criminal justice system in the media, most incarceration and law enforcement take place at the local level. “About 87 percent of all prisoners are held in state systems,” Pfaff writes. “The federal government runs the single largest prison system, but several states have systems that are fairly close to the federal one in size, and if we look at total populations under some sort of correctional observation (not just prison, but also jail, parole, and probation), the federal government quickly falls out of first place.”

The focus on the federal prison system may explain why many in the media and other experts think that drug offenses are such a huge driver of incarceration. In the federal system, about half of prisoners are in for drug crimes — more than three times the rate of the state systems.

But given that the state systems contain a much larger bulk of the prison population, Pfaff argues the fight to end mass incarceration should focus at the local and state level — and that means focusing on crimes that go far beyond drugs.

Emphasis on local. “Take New York, a state that has experienced one of the longest sustained decarcerations in recent history, with prison populations falling by about 25 percent since 1999,” Pfaff writes. “This looks like a state success story, but the entire decline between 2000 and 2011 took place in just twelve of the state’s sixty-two counties, with the other fifty counties adding inmates to state prisons during that time.”

The federal government does have some sway over local and state prison systems. But Pfaff argues that this influence is perhaps not as strong as people think.

To demonstrate this, he looks at the federal government’s main tool for driving criminal justice policies at the local and state levels: grant money. These funds are supposed to encourage local and state government to adopt certain policies, but they’re just not sizable enough to make a big impact.

“Between 1993 and 2012, eight major grant-making arms of the US Department of Justice awarded about $38 billion to state and local governments,” Pfaff writes. “As a percentage of annual criminal justice spending, these grants consistently hovered (in total) around 2 percent for the states and under 1 percent for local governments.”

In short, the federal government’s war on drugs never played much of a role in incarceration because the federal government just doesn’t play much of a role in incarceration overall.

Prosecutors are enormously powerful, yet rarely discussed in reform efforts

Typically, discussions of the criminal justice system focus on lawmakers, prisons, the police, and maybe judges. Rarely, however, is the most powerful actor in this system mentioned: the prosecutor.

Local and state prosecutors are enormously powerful in the US criminal justice system, in large part because they are given so much discretion to prosecute however they see fit. For example, former Brooklyn District Attorney Kenneth Thompson in 2014 announced that he would no longer enforce low-level marijuana arrests. Think about how this works: Pot is still very much illegal in New York state, but Brooklyn’s district attorney flat-out said that he would ignore an aspect of the law — and it’s completely within his discretion to do so.

Prosecutors make these types of decisions all the time: Should they bring the type of charge that will trigger a lengthy mandatory minimum sentence? Should they bring a charge that’s only a misdemeanor? Should they strike a deal for a lower sentence, but one that can be imposed without a costly trial?

Courts and juries do, in theory, act as checks on prosecutors. But in practice, they don’t: More than 90 percent of criminal convictions are resolved through a plea agreement, so by and large prosecutors and defendants — not judges and juries — have almost all the say in the great majority of cases that result in incarceration or some other punishment.

Many prosecutors are also elected. This, too, is supposed to keep prosecutors in check. But in practice, prosecutors try to appease the electorate by looking “tough on crime” — and that means imposing harsh prison sentences, as well as locking up as many “bad guys” as possible. (This may go against voters’ wishes, but another problem is voters don’t actually do much to hold prosecutors accountable: When Ronald Wright of Wake Forest University School of Law looked at data from 1996 to 2006, he found that about 95 percent of incumbent prosecutors won reelection, and 85 percent ran unopposed in general elections.)

Pfaff has even found evidence that prosecutors have been the key drivers of mass incarceration in the past couple of decades. Analyzing data from state judiciaries, he compared the number of crimes, arrests, and prosecutions from 1994 to 2008. He found that reported violent and property crime fell, and arrests for almost all crimes also fell. But one thing went up: the number of felony cases filed in court.

Prosecutors were filing more charges even as crime and arrests dropped, throwing more people into the prison system. Prosecutors were driving mass incarceration.

Pfaff provides a real-world example of this kind of dynamic: “Take South Dakota, which in 2013 passed a reform bill that aimed to reduce prison populations. The law did lead to prison declines in 2014 and 2015, yet at the same time prosecutors responded by charging more people with generally low-level felonies, and over these two years total felony convictions rose by 25 percent.” In the long term, this could lead to even larger prison populations.

To combat this, Pfaff argues that states could enact, for example, prosecutorial guidelines that limit the amount of discretion these officials have.

“Almost all stages of the criminal justice system now operate under some sort of guideline or actuarial regime,” he writes. “The lone exception is the prosecutor. Although prosecutors need room to exercise discretion, their job is not so uniquely different from the other parts of the criminal justice system that they alone cannot do it if they are subjected to some sort of guidance.”

Yet, he explains, “No major piece of state-level reform legislation has directly challenged prosecutorial power (although some reforms do in fact impede it), and other than a few, generally local exceptions, their power is rarely a topic in the national debate over criminal justice reform.”

The bottom line: Mass incarceration is about way more than the federal war on drugs

Piece by piece, Pfaff paints a more nuanced picture of the criminal justice systems in America than that of the Standard Story. In the end, it’s not that the war on drugs or the federal system doesn’t matter; it’s that they both play a much smaller role than they are typically given credit for. Pfaff goes through similar data on private prisons, the length of certain prison sentences, and other Standard Story tropes — showing that they all tend to get outsize attention given their actual impact on incarceration.

It all points to one conclusion: To truly eliminate mass incarceration, reformers will have to at some point shift more attention to dealing with the mass incarceration of violent offenders, not just low-level drug offenders, and do so with a focus on the state and local levels, particularly prosecutors in these areas.

This puts reformers and lawmakers who want to end mass incarceration in a much more difficult situation. For one, it’s going to be way more challenging to advocate for lower sentences and fewer admissions for violent offenders.

A poll conducted by Morning Consult for Vox last year, for example, found that nearly eight in 10 US voters support reducing prison sentences for people who committed a nonviolent crime and have a low risk of reoffending. But fewer than three in 10 backed shorter prison sentences for people who committed a violent crime and have a low risk of reoffending.

Pfaff tries his hand at some of the messaging that will be needed here: He argues that incarceration is simply an ineffective way to combat crime, while it imposes all sorts of costs on individuals and society that likely outweigh its benefits.

“It’s true that crime is costly — but so, too, is punishment, especially prison,” he writes. “The real costs are much higher than the $80 billion we spend each year on prisons and jails: they include a host of financial, physical, emotional, and social costs to inmates, their families, and communities. Maybe reducing these costs justifies some rise in crime.”

It’s hard to imagine Americans buying Pfaff’s suggestion that we should accept more crime. But he’s certainly right that prison is an ineffective way of dealing with crime, based on much of the research in this area.

A 2015 review of the research by the Brennan Center for Justice estimated that more incarceration — and its abilities to incapacitate or deter criminals — explained about 0 to 7 percent of the crime drop since the 1990s. Other researchers estimate it drove 10 to 25 percent of the crime drop since the ’90s.

More incarceration can lead even to more crime. As the National Institute of Justice concluded in 2016, “Research has found evidence that prison can exacerbate, not reduce, recidivism. Prisons themselves may be schools for learning to commit crimes.”

Meanwhile, criminal justice experts have come up with all sorts of other solutions to combating crime. There are new police strategies — such as “hot-spot policing” and “focused deterrence” — that have measurable impacts on crime, including violence. There are other ideas focused more on socioeconomic issues, such as stricter alcohol policies, raising the age for dropping out of school, and some behavioral intervention programs.

“Besides prison, crime is shaped by the number of police, the unemployment rate, wage levels, the number of crime-aged young men in the population, immigration levels, cultural attitudes toward violence, technological improvements, and so much more,” Pfaff writes.

This creates a lot more room to enact policies that are less brutal and much more efficient at dealing with crime than prisons are. “Hiring a police officer is probably about as expensive as hiring a prison guard, for example, but investing in police has a much bigger deterrent effect and avoids all the capital expenditures of prisons,” Pfaff argues. “Steven Levitt has estimated that $1 spent on policing is at least 20 percent more effective than $1 spent on prisons.”

In an ideal world, maybe America would spend infinite money on these programs and stop all crime forever. But resources are limited. So the US and the different criminal justice systems within it could see better results if they put the money they do have toward anti-crime policies other than prison.

Adopting this sort of perspective on criminal justice issues, Pfaff argues, is crucial to undoing mass incarceration. The important thing here isn’t just to pass laws that cut prison sentences or make it harder to lock someone up, but to fundamentally alter the way that Americans and their leaders think of crime in America. Only then can the US adopt the kind of mentality that will push against “tough on crime” attitudes even as the crime rate goes up.

After all, even if the US did enact a bunch of reforms now, there’s always the fear of a future crime wave, Pfaff explains: “If crime starts to really rise again, which almost certainly will happen at some point, there’s nothing to prevent legislators from rolling back the current reforms and overreacting once more.” He later added, “It is a change in attitude, more than anything else, that will prevent legislatures from bringing back tough laws they earlier repealed.”

That’s why work like Pfaff’s is so important: Only by understanding the real causes of mass incarceration can the public and policymakers be prepared to undo and resist it now and in the future.