A large body of evidence confirms the value of keeping violent and repeat criminals in prison.

• Studies show that crime depresses local business development and erodes local economies.

• Even excluding drug sales, the typical prisoner commits 12 crimes a year when he is not in prison.

• The best estimate is that each street crime costs victims and society at least $2,300 in pain, suffering and economic losses.

• Thus the social benefit of imprisoning the typical felon is $27,600, whereas the average cost of keeping a criminal behind bars is about $25,000 a year.

Most people in prison are violent or repeat criminals or both.

• About 90 percent have two or more felony convictions or are violent offenders.

• Even in the federal prisons, which house more white-collar criminals, more than half of all prisoners have two or more prior convictions, and 46 percent have committed one or more crimes of violence.

The negative effects of prison overcrowding have been exaggerated. Further, most prisons are not "hell holes" or "schools of crime."

Source: John J. DiIulio, Jr., "The Value of Prisons," Wall Street Journal, May 13, 1992.