The view from Schmitt,Warner, and Gupta (2010):
The United States currently incarcerates a higher share of its population than any other country in the world. We calculate that a reduction in incarceration rates just to the level we had in 1993 (which was already high by historical standards) would lower correctional expenditures by $16.9 billion per year, with the large majority of these savings accruing to financially squeezed state and local governments. As a group, state governments could save $7.6 billion, while local governments could save $7.2 billion.
These cost savings could be realized through a reduction by one-half in the incarceration rate of exclusively non-violent offenders, who now make up over 60 percent of the prison and jail population.
Missouri Supreme Court Chief Justice William Price puts this into perspective for Missouri in a Feb. 3rd, 2010 speech:
Perhaps the biggest waste of resources in all of state government is the over-incarceration of nonviolent offenders and our mishandling of drug and alcohol offenders. It is costing us billions of dollars and it is not making a dent in crime.
Listen to these numbers. In 1994, shortly after I came to the Court, the number of nonviolent offenders in Missouri prisons was 7,461. Today it’s 14,204. That’s almost double. In 1994, the number of new commitments for nonviolent offenses was 4,857. Last year, it was 7,220 — again, almost double. At a rate of $16,432 per offender, we currently are spending $233.4 million a year to incarcerate nonviolent offenders … not counting the investment in the 10 prisons it takes to hold these individuals at $100 million per prison. In 1994, appropriations to the Department of Corrections totaled $216,753,472. Today, it’s $670,079,452. The amount has tripled. And the recidivism rate for these individuals, who are returned to prison within just two years, is 41.6 percent.
Here is a graph, again from CEPR:
The problem is that this makes sense.