The Better Angels of Our Nature: Why Vio - By Steven Pinker Page 0,76

people who commit the most crimes expose themselves to the most opportunities to get caught, and so they are the ones most likely to be skimmed off and sent to jail. Moreover, people who commit violent crimes get into trouble in other ways, because they tend to favor instant gratification over long-term benefits. They are more likely to drop out of school, quit work, get into accidents, provoke fights, engage in petty theft and vandalism, and abuse alcohol and drugs.158 A regime that trawls for drug users or other petty delinquents will net a certain number of violent people as bycatch, further thinning the ranks of the violent people who remain on the streets.

Incarceration can also reduce violence by the familiar but less direct route of deterrence. An ex-convict might think twice about committing another crime once he gets out of jail, and the people who know about him might think twice about following in his footsteps. But proving that incarceration deters people (as opposed to incapacitating them) is easier said than done, because the statistics at any time are inherently stacked against it. The regions with the highest rates of crime will throw the most people in jail, creating the illusion that imprisonment increases crime rather than decreasing it. But with suitable ingenuity (for example, correlating increases in imprisonment at one time with decreases in crime at a later time, or seeing if a court order to reduce the prison population leads to a subsequent increase in crime), the deterrence effect can be tested. Analyses by Levitt and other statisticians of crime suggest that deterrence works.159 Those who prefer real-world experiments to sophisticated statistics may take note of the Montreal police strike of 1969. Within hours of the gendarmes abandoning their posts, that famously safe city was hit with six bank robberies, twelve arsons, a hundred lootings, and two homicides before the Mounties were called in to restore order.160

But the case that the incarceration boom led to the crime decline is far from watertight.161 For one thing, the prison bulge began in the 1980s, but violence did not decline until a decade later. For another, Canada did not go on an imprisonment binge, but its violence rate went down too. These facts don’t disprove the theory that imprisonment mattered, but they force it to make additional assumptions, such as that the effect of imprisonment builds up over time, reaches a critical mass, and spills over national borders.

Mass incarceration, even if it does lower violence, introduces problems of its own. Once the most violent individuals have been locked up, imprisoning more of them rapidly reaches a point of diminishing returns, because each additional prisoner become less and less dangerous, and pulling them off the streets makes a smaller and smaller dent in the violence rate.162 Also, since people tend to get less violent as they get older, keeping men in prison beyond a certain point does little to reduce crime. For all these reasons, there is an optimum rate of incarceration. It’s unlikely that the American criminal justice system will find it, because electoral politics keep ratcheting the incarceration rate upward, particularly in jurisdictions in which judges are elected rather than appointed. Any candidate who suggests that too many people are going to jail for too long will be targeted in an opponent’s television ads as “soft on crime” and booted out of office. The result is that the United States imprisons far more people than it should, with disproportionate harm falling on African American communities who have been stripped of large numbers of men.

A second way in which Leviathan became more effective in the 1990s was a ballooning of the police.163 In a stroke of political genius, President Bill Clinton undercut his conservative opponents in 1994 by supporting legislation that promised to add 100,000 officers to the nation’s police forces. Additional cops not only nab more criminals but are more noticeable by their presence, deterring people from committing crimes in the first place. And many of the police earned back their old nickname flatfoots by walking a beat and keeping an eye on the neighborhood rather than sitting in cars and awaiting a radio call before speeding to a crime scene. In some cities, like Boston, the police were accompanied by parole officers who knew the worst troublemakers individually and had the power to have them rearrested for the slightest infraction.164 In New York, police headquarters tracked neighborhood crime reports obsessively and held captains’ feet to the fire if