The recession crime free fall continues a trend of declining national crime rates that began in the 1990s, during a very different economy. The causes of that long-term drop are hotly disputed, but an increase in the number of people incarcerated had a large effect on crime in the last decade and continues to affect crime rates today, however much anti-incarceration activists deny it. The number of state and federal prisoners grew fivefold between 1977 and 2008, from 300,000 to 1.6 million.

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The spread of data-driven policing has also contributed to the 2000s' crime drop. At the start of the recession, the two police chiefs who confidently announced that their cities' crime rates would remain recession-proof were Los Angeles Police Chief William Bratton and New York Police Commissioner Ray Kelly. As New York Police Commissioner in the mid-1990s, Mr. Bratton pioneered the intensive use of crime data to determine policing strategies and to hold precinct commanders accountable--a process known as Compstat. Commissioner Kelly has continued Mr. Bratton's revolutionary policies, leading to New York's stunning 16-year 77% crime drop. The two police leaders were true to their word. In 2009, the city of L.A. saw a 17% drop in homicides, an 8% drop in property crimes, and a 10% drop in violent crimes. In New York, homicides fell 19%, to their lowest level since reliable records were first kept in 1963.

The Compstat mentality is the opposite of root causes excuse-making; it holds that policing can and must control crime for the sake of urban economic viability. More and more police chiefs have adopted the Compstat philosophy of crime-fighting and the information-based policing techniques that it spawned. Their success in lowering crime shows that the government can control antisocial behavior and provide public safety through enforcing the rule of law. Moreover, the state has the moral right and obligation to do so, regardless of economic conditions or income inequality.

The recession could still affect crime rates if cities cut their police forces and states start releasing prisoners early. Both forms of cost-saving would be self-defeating. Public safety is the precondition for thriving urban life. In 1990s New York, crime did not drop because the economy improved; rather, the city's economy revived because crime was cut in half. Keeping crime rates low now is the best guarantee that cities across the country will be able to exploit the inevitable economic recovery when it comes.