Prisons are absolutely necessary for public safety, but prison beds are an expensive resource. Michigan is not managing this resource well.

It costs more to incarcerate a prisoner in Michigan than in any other state in the Midwest, according to a recent Senate Fiscal Agency analysis. And the financial burden of jailing prisoners has increased dramatically in the last two decades.

In the 1988 budget year, state Corrections Department spending accounted for 8.5 percent of the general fund. In the governor's proposed 2008 budget, prison spending, at $1.9 billion, amounts to 20 percent of the general fund budget.

The number of inmates held in Michigan's prisons and camps is more than 51,000, more than twice the number of prisoners in 1988.

Michigan imprisons a higher share of its population than the surrounding states or the national average. The Senate analysis, published last month, notes that in 2005, the last year for which comparable data is available, Michigan incarcerated 489 people per 100,000 of its residents; the national average was 401. This state ranked 11th in the nation in the percent of its population behind bars.

Certainly, Michigan must continue to be aggressive in locking up violent criminals. But it can sensibly reduce prison costs without sacrificing public safety.

Oakland County Sheriff Michael Bouchard, for example, reports that he saves $1.6 million annually by competitively bidding food services for his 2,000 county prisoners. He has also saved close to half a million dollars by privatizing the pharmacy for prisoners. State prisons would find savings on a much grander scale by taking similar steps.

Sentencing and parole policies have been driven by horrific crimes committed by people who have been erroneously released from prison. But the remedy for these mistakes is not to keep everyone jailed for as long as possible.

In the early 1990s, there was a spate of awful sex crimes committed by released offenders. As a result, parole procedures were tightened. In 1990, the parole board approved the parole applications of 46.5 percent of sex offenders who came before it. Last year, 10 percent of such applications were approved for sex offenders. About 35 percent of other violent offenders had their parole applications granted, down from 61 percent in 1990.

The Senate Fiscal Agency analysis suggested that a recent slowdown in paroles could be a result of the accidental release of Patrick Selepak, who went on a murder, robbery and kidnapping spree before entering a guilty plea last year.

But this kind of bungling shouldn't drive all decisions on releasing inmates. This spring, Gov. Jennifer Granholm proposed the release over two years of more than 5,000 aging or medically fragile prisoners, along with inmates who could be deported to other countries. This is a sensible move.

In addition to a stepped-up review of likely prisoners for release, the governor is recommending an increase in funding for a prisoner re-entry program in which parolees receive more intense monitoring and support in the community. Early results from a pilot program show a reduction in repeat crimes by parolees of 20 percent.

Legislation in the House to reform the parole process to make it less rigid and allow inmates to appeal decisions should be adopted.

Finally, the governor has proposed sentencing reforms. She and lawmakers need to work together to craft reforms to keep more nonviolent and minor offenders out of prison. Not everyone who commits a crime is a danger to society. Other, less expensive means of punishment should be explored.

Sentencing reform is ultimately the key to keeping prison costs under control. As Corrections spokesman Russ Marlan notes, "We can release inmates. But without sentencing reform, we'll just keep filling up the prisons."