It is generally attributed by those on the streets fighting crime, that the two most powerful deterrents to crime—broken-windows policing and three-strikes sentencing—have finally reached a point of large national impact and lower crime rates are the result.
This article from the Washington Post continues the argument that the reasons are largely unknown.
“AS YOU HAVE no doubt heard, the first 10 years of the 21st century were dreadful -- a lost decade of terrorism, war and economic stagnation. There is some truth to that portrayal. But in one significant respect, the awful Aughties were practically a golden age. We refer to the continued progress the United States is making against homicide and other violent crime.
“According to some conventional wisdom, economic trouble breeds lawlessness. Yet in the first half of 2009, as unemployment skyrocketed, reported murders, forcible rapes, robberies and aggravated assaults decreased by 4.4 percent compared with the first half of 2008, according to the FBI. The decline in homicide was especially striking: down 29.8 percent in Los Angeles, 14 percent in Atlanta, 10 percent in Boston. With 461 murders through Dec. 27, New York was on track for the lowest number since comprehensive record-keeping began in 1963 -- when the Big Apple was a slightly smaller town. …
“If only we knew exactly why and how it has occurred. An accident of demography? The passing of the crack cocaine epidemic? We're inclined to credit policies that put more brave and dedicated cops on the street, with better technology and smarter tactics. Still New York City continued to rack up lower homicide rates in the past decade even as its police force shrank by 6,000. New York officials say that city's tougher gun laws have helped; yet Houston also recorded a drop in homicide in the first half of 2009 despite loose gun laws.”