Overshadowed by campaign mudslinging and the approach of Hurricane Sandy, Gov. Tom Corbett signed into law a prison-reform measure last week that had passed the Legislature with rare bipartisan support. The law is expected to save state taxpayers $100 million over five years and also is designed to help prisoners integrate into society, reducing the probability of returning to prison.

Motivation for prison reform is both financial and humane. The state corrections system now costs about $2 billion a year in a $2.7 billion budget. That’s a tripling of prison-related costs over 30 years and to all observers is on an unsustainable path.

Taxpayers spend about $34,000 a year to keep an inmate in one of Pennsylvania’s 26 state prisons. And in the past three decades, the number of inmates has jumped to 51,000 from about 10,000.

Recidivism costs the state money that would be better spent on treatment and post-release follow-up support to prevent people from returning to prison after release. Some of the treatment and support programs can also keep some nonviolent offenders from spending time in prison in the first place.

For too long, the attitude across most of America, including Pennsylvania, has been to be tough on crime. But mounting evidence proves that a “lock ’em up and throw away the key” approach is not reducing crime and is costing billions of dollars.

A new approach is needed. State Sen. Stewart Greenleaf, R-Montgomery, a longtime advocate for prison reform, said about the new law, “We can be tough on crime, but we have to be smart on crime.”

Most of the reforms focus on non-violent criminals and those with drug addictions or mental health issues.

A part of the law, which was passed separately in the spring, encourages the use of alternative sentencing for nonviolent crimes that also involve outpatient treatment for drug addiction, the root problem for many people in the criminal justice system.

But effective prison reform faces the challenge of finding a balance between spending and public safety. Efforts at reducing recidivism have generally produced mixed results. There is no magic formula or simple program for keeping people out of prison.

But just because it is difficult and might yield mixed results is not a reason to avoid prison reform. Pennsylvania’s efforts mirror those in California, Oregon, Texas and others. Across the country, tough on crime and “three strikes and you’re out” attitudes are being rethought — mostly because of the stunning costs associated with rapidly escalating prison populations.

People also are realizing that putting every lawbreaker behind bars, including nonviolent criminals with underlying addiction or mental health issues, is not the answer — from a financial perspective or from a compassion perspective.

Prison reform should save money, but for the program to be effective, a significant part of those savings will have to be re-directed into other programs in the criminal justice or treatment system. Those include counseling, follow-up support, specialty courts and possibly job training.

Prison reform is a challenge, and keeping people out of prison — or from returning to prison — is difficult, no matter how much help is offered. But prison reform is necessary, along with possibly updated sentencing guidelines, now that it is clear that what we’ve been doing for the past 30 years is not working.