According to the FBI, the national homicide rate dropped 10 percent in 2009. Property crimes also dropped significantly in 2009. Crime, broadly speaking, is now at levels not seen since the early 1960s. No longer is this just a New York City miracle. It’s a national story.

Why did that happen?

Crime used to be the most ideological debate point in American politics. Liberals attributed crime’s increase in the late 1960s, 1970s and 1980s to deindustrialization and increasing class divides. Conservatives blamed lax moral standards and a judicial system too friendly to criminals.

Then crime started to drop around 1995. This happened in high-profile cities like New York and in lower profile cities across the country. Some credited the end of the crack wars, others more aggressive community policing, others the harsh sentencing regimen of the War on Drugs, and others the economic gains for African Americans in the Clinton years. After leveling off in the mid-00s crime went down again this last year.

Again, there are ideological arguments abundant. Conservatives cite looser gun laws giving law-abiding citizens the ability to defend themselves (though still gun-unfriendly cities like DC have seen major drops in crime too). And some credit a black President with steering some previously disaffected African American youth away from a life of crime (though crime has dropped among whites too).

But I think the real reason is the economy. It seems counterintuitive that a recession would cause crime to go down. After all, massive joblessness means more desperate people looking for money, right?

But the 1930s showed a similar trend – crime actually bottomed out in that decade too.

Part of the explanation may be that there just aren’t that many people to steal from – though that was always the case in poor inner city neighborhoods.

I think what’s happened is that the general economic downturn has simply lowered economic expectations to the point that fringe elements of the population don’t feel like they’re missing out on their share of the wealth. In times of national abundance the poor feel that they aren’t “getting paid” and so must do whatever is necessary to make ends meet. In comes the New Jack City culture of the 1980s and early 1990s where inner city youth sought the instant wealth that seemed universal outside the ghetto.

In 2009 there is little of the culturally-driven envy – or get-rich-quick underground economy – of the 1980s. There’s a resurgent drug culture – methamphetatimine here in Appalachia and Mexican cartel-supplied cocaine in the cities. But the massive drug gang war seems not to have accompanied it for now. The drugs are there, but the jealousy isn’t.

This is all just a theory, of course. Crime is driven by many factors. But financial expectation – more than objective class reality – is a major driver behind both property and violent crime. When the suffering is broadly felt the poor are less likely to turn to crime.