It's hardly news that America's commitment to a policy of mass incarceration has produced the most locked-up society on the planet. With more than 2.3 million people behind bars, America has the highest incarceration rate of any country, ten times higher than some European countries. The toll this takes on the country's economy, government budgets, families, and social fabric is well documented. But defenders of mass incarceration have argued that whatever its costs, it has been effective. Crime after all, has dropped precipitously in the last 30 years.
But a report released Thursday by New York University's Brennan Center for Social Justice guts that claim. "When other variables are controlled for, increasing incarceration had a minimal effect on reducing property crime in the 1990s and no effect on violent crime," the authors found. "In the 2000s, increased incarceration had no effect on violent crime and accounted for less than one-hundredth of the decade's property crime drop."
When incarceration rates are low, the Brennan Center report suggests, putting more people behind bars can actually have some effect on crime. But that effect diminishes as you keep locking folks up. That's partly because, when you put more people in prison, fewer of the them are hardened career criminals. It's also because incarceration is itself "criminogenic"—a stint in prison can lead people to commit crimes they wouldn't have otherwise.
More influential on the drop and crime, the report finds, are social and economic factors like the aging population and decreased alcohol consumption, as well as the proliferation of data-driven policing, commonly known as CompStat. The report also considers some of the more unusual theories proposed for explaining the decline in crime, including decreased lead exposure and legalized abortion, but finds that while the influence of these factors during the 1990s can't be entirely ruled out, they're unlikely to have had any meaningful impact on crime in the last 15 years.
There is some good news in the report: In the 2000s, 14 states managed to reverse the mass incarceration trend, cutting their prison populations while also managing to continue to reduce crime. In New York, where that trend is most dramatic, the state reduced imprisonment by 26 percent at the same time that property crimes dropped by 28 percent.
But even if some states appear to be starting to slow the legal machinery that pumps citizens into prisons, that's only one piece of the problem. A report issued Wednesday by the Vera Institute of Justice examines the nation's jails. Unlike prisons, which are run by the federal or state governments, America's jails are locally run by municipalities or counties, holding inmates awaiting trial and people convicted of relatively minor crimes.
The Vera report found that there were 11.7 million admissions to US jails in 2013—more than the population of Los Angeles. Even as violent and property crime rates began to decline in the 90s, the jail intake continued to surge, nearly doubling over the last 30 years. Much of that growth is attributable to an increase in the number of defendants jailed on drug charges as the war on drugs accelerated. But the report also highlights the overwhelming rate at which people with mental illness are being warehoused in jails, citing a finding by the Bureau of Justice Statistics that fully 60 percent of inmates reported having symptoms of a mental health problem in the previous year. Of course, the racial disparity of jail populations is unlikely to surprise most people, as is the degree to which the use of bail and other factors disproportionately send poor Americans to jail.
In recent years there's been a growing awareness and acknowledgment of the socially destructive consequences of mass incarceration, its staggering expense, and the demonstrable injustice of its administration. These reports provide further ammunition to critics of American incarceration policy, and could serve to foster the kind of conversation about mass incarceration that last year's police shootings started about law enforcement.
As Columbia Economics Professor and Nobel Prize winner Joseph Stiglitz writes in his introduction to the Brennan Center report, "The United States has limited resources. We must foster opportunity and work to bridge inequality, not fund policies that destroy human potential today and handicap the next generation. The toll of mass incarceration on our social and economic future is unsustainable."
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