Last year the U.S. prison population declined for the first time in a generation. That's good news, but it doesn't begin to offset the damage done by a 30-year incarceration binge that has made America far and away the democratic world's leader in putting people behind bars.

The numbers are staggering. In 1970 one in 400 American adults was behind bars or on parole. As of 2008, the number was one in 100. Add in probation, and it's one in 31. The number of people behind bars for drug crimes has soared from 40,000 in 1980 to about half a million today. States today spend one of every 15 general fund dollars on maintaining their prisons. According to the King's College World Prison Population List (PDF), the U.S. is home to 5 percent of the world's population but nearly a fourth of its prisoners. Judging by these official numbers, America's incarceration rate leads the developed world by a large margin, although it's doubtful that authoritarian regimes such as China's are providing accurate data, especially about political prisoners. But among liberal democracies, the competition isn't even close: As of 2008, the U.S. incarceration rate was 756 per 100,000 people, compared to 288 for Latvia, 153 for England and Wales, 96 for France, and 63 for Denmark.

America's soaring prison population has spawned much debate over issues such as the wisdom of mandatory minimum sentences, the financial burden that prisons impose on states struggling with budget shortfalls, and the degree to which incarceration explains the dramatic drop in crime during the last 20 years. But the United States has never had such a high percentage of its citizens behind bars, and we really have no idea what long-term effects the tough-on-crime policies of the last few decades will have. During the next decade, for example, we will start to see the release of nonviolent drug offenders hit with the draconian prison sentences Congress established in the 1980s. It isn't hard to see how locking a drug offender up with violent criminals for two decades and then releasing him into the population as a convicted felon might portend some bad results.

There are other problems. We have a record number of women behind bars, many of them pregnant or mothers of small children. This is a trend state governments aren't handling well. The prison population is aging, a problem made worse by policies like abolishing parole. Since Virginia lawmakers abolished parole in 1995, The Washington Post reported in September, the number of prisoners over 50 in the state's correctional system has increased fourfold. If our prison habit is expensive now, just wait until taxpayers are covering medical care as the front end of the prison boom enters its golden years. (Interestingly, prison doesn't seem to significantly shorten life spans; black men actually live longer in prison than they do outside.)

There may be lingering, intergenerational problems too. While income inequality rises and falls, America has always boasted healthy economic mobility—the ability of earners in lower income brackets to move up in a relatively short period of time. But the authors of a recent Pew Charitable Trusts study published in the social science journal Daedelus argue that mass incarceration may be crippling mobility. Sociologists Bruce Western of Harvard and Becky Pettit of the University of Washington write that the handicap associated with a criminal record and time in prison can linger for decades, affecting not just felons themselves but their families, social networks, and neighborhoods as well.

Western and Pettit note that high school dropouts without felony records do substantially better than high school dropouts who have done time. Perhaps that's not surprising; we'd expect that committing a felony would limit one's earning potential, and some might even welcome that effect as part of the punishment. But Western and Pettit argue that it's actual incarceration, not the felony record, that's most limiting. Long-term incarceration severs old social networks, instead fostering new networks with other criminals. Child support obligations accumulate while men are incarcerated, hitting them with debt upon release that limits their ability to establish themselves financially. If the aim of the correctional system is to stunt offenders for life, we're doing fine. If it's to integrate them back into society after they've done their time, we're coming up short.

Most worrisome is the effect on the children of incarcerated parents and the potential for an intergenerational "stickiness" in the lower income brackets. In 1985, Western and Pettit note, one in every 125 American children had a parent behind bars. Today it's one in 28. For black children, it's one in nine, a fourfold increase during the last 25 years. While we have yet to see any long-term studies on the income mobility of convicts' children, it seems safe to say having a parent behind bars can't help. Sons of incarcerated parents are five times more likely to be suspended from school, and about half of incarcerated parents were the primary income earners for their kids. These facts suggest that children of incarcerated parents are not just unlikely to achieve upward economic mobility; they are also prime candidates to become second-generation inhabitants of the correctional system.

How to reverse or ameliorate the damage already done is a debate we'll be having for decades. But there is one change that could at least stop the bleeding: less democracy. As New York Times reporter Adam Liptak pointed out in a 2008 article, America's soaring incarceration rate may be largely due to the fact that we have one of the most politicized criminal justice systems in the developed world. In most states, judges and prosecutors are elected, making them more susceptible to slogan-based crime policy and an electorate driven by often irrational fear. While the crime rate has fallen dramatically since the early 1990s, polls consistently show that the public still thinks crime is getting worse.

In response to these fears, legislators have increasingly eroded the discretion of prosecutors and judges (already subject to political pressures) in charging defendants and imposing sentences. Under the theory that more punishment is always better, lawmakers have imposed mandatory minimum sentences, made parole and probation more difficult, and decreed that mere possession of drugs above a certain quantity is automatically treated as distribution. The democratic demand for such policies may be clearest in California, where it is relatively easy to pass legislation through ballot initiatives. Such initiatives have led to some of the toughest crime policies in the country—and nearly twice as many prisoners as the state's prisons are supposed to hold.

The good news is that these issues are finally getting some attention, and there's some evidence that public opinion on crime and punishment may finally be shifting. If that's true, the key will be using that momentum to not only change bad laws but to add institutional reforms that better insulate the criminal justice system from politics.

Radley Balko is a senior editor at Reason magazine.