In the 1990s, John DiIulio, a conservative American academic, argued that a new breed of "superpredators," "kids that have absolutely no respect for human life and no sense of the future," would terrorize Americans almost indefinitely. He was not alone. Experts were convinced that crime would keep rising. Law-abiding citizens would retreat to gated communities, patrolled by security guards. Politicians and police chiefs could do little except bluster and try to fiddle the statistics.
DiIulio later recanted, and it is clear that the pessimists were wrong.
Even as DiIulio was writing, America's crime wave was breaking. Its cities have become vastly safer, and the rest of the developed world has followed. From Japan to Estonia, property and people are now safer than at almost any time since the 1970s. Confounding expectations, the recession has not interrupted the downward trend. Even as America furiously debates the shooting of Trayvon Martin, new data show that the homicide rate for young Americans is at a 30-year low.
Some crimes have all but died out. Last year, there were just 69 armed robberies of banks, building societies and post offices in England and Wales, compared with 500 a year in the 1990s. In 1990, some 147,000 cars were stolen in New York. Last year, fewer than 10,000 were. In the Netherlands and Switzerland, street dealers and hustlers have been driven out of city centers; addicts there are now elderly men, often alcoholics, living in state hostels.
In countries like Lithuania and Poland, the gangsters who trafficked people and drugs in the 1990s have moved into less violent activities like fraud.
Cherished social theories have been discarded. Conservatives who insisted that the decline of the traditional nuclear family and growing ethnic diversity would unleash an unstoppable crime wave have been proved wrong.
Young people are increasingly likely to have been brought up by one parent and to have played a lot of computer games. Yet they are far better behaved than previous generations. Left-wingers who argued that crime could never be curbed unless inequality was reduced look just as silly.
There is no single cause of the decline; rather, several have coincided.
Western societies are growing older, and most crimes are committed by young men. Policing has improved greatly in recent decades, especially in big cities like New York and London, with forces using computers to analyze the incidence of crime. In some parts of Manhattan, this helped to reduce the robbery rate by more than 95 percent. The epidemics of crack cocaine and heroin appear to have burned out.
The biggest factor may be simply that security measures have improved. Car immobilizers have killed joyriding; bulletproof screens, security guards and marked money have all but done in bank robbery. Alarms and DNA databases have increased the chances a burglar will be caught. At the same time, the rewards for burglary have fallen because electronic gizmos are so cheap. Even small shops now invest in closed-circuit television cameras and security tags. Some crimes now look very risky — and that matters because, as every survey of criminals shows, the main deterrent for crime is the fear of being caught.
Many conservatives will think this list omits the main reason crime has declined: the far harsher prison sentences introduced on both sides of the Atlantic over the past two decades. One in every hundred American adults is now in prison. This has obviously had some effect — a young man in prison cannot steal your car — but if tough prison sentences were the cause, crime would not be falling in the Netherlands and Germany, which have reduced their prison populations. New York's prison population has fallen by a quarter since 1999, yet its crime rate has dropped faster than that of many other cities.