“The number of very tenable explanations for the crime drop [of the 1990s], none of which inherently excludes any of the others, leads to the conclusion that . . . a variety of factors . . . have been important.” —Alfred Blumstein and Joel Wallman, The Crime Drop in America

The good news on crime is that, since 1993, the United States has been experiencing a sweeping decline in crime rates. According to the Justice Department’s National Crime Victimization Survey, between 1993 and 2002 the violent crime rate decreased 54 percent, from fifty to twenty-three victimizations per one thousand persons age twelve or older. Rape and sexual assault decreased by 56 percent during this period, robbery rates fell by 63 percent, and aggravated assaults (assaults associated with weapon use or serious injury) were down 64 percent between 1993 and 2002. The property crime rate declined 50 percent, from 319 to 159 crimes per one thousand households. The household burglary rate fell...