Signs can be found nationwide that what critics call America's "love affair" with incarcerating prisoners may be coming to an end.

The legislature of Washington state, which passed the nation's first three-strikes-you're-out law (search) by popular initiative a decade ago, recently passed a series of laws weakening it. Kansas now orders first-time drug offenders to treatment rather than prison, provided they didn't commit a crime that involved violence. Michigan has dropped its lengthy mandatory-minimum sentences for drug offenders. Iowa, Missouri and Wisconsin have eased their "truth in sentencing" laws (search), which require inmates to serve nearly their entire sentences before being eligible for parole.

In the last year, 25 states have sought to reduce the burden on their budgets and their corrections systems by weakening mandatory-sentencing statutes, reforming post-release requirements and restoring parole. Those proposing these measures come from both sides of the political aisle and from every level of government. They include sheriffs and police chiefs, legislators and members of Congress, governors and prison executives.

But if Alan Elsner, an author who focuses on criminal-justice issues, was correct in a recent op-ed for The Washington Post that our "love affair" with incarcerating dangerous criminals is waning, those proposing the changes are going to find that breaking up is hard to do. Americans have come to rely on the criminal-justice system to keep hard-core offenders locked up, and they won't think it's worth it when-- in the name of cost-cutting-- rapes, murders and other violent crimes go up by the thousands as a result of any veiled efforts to extend leniency to offenders who clearly don't deserve it.

The American people understand their state governments are in financial crisis and that the federal government expects record deficits in the near future. They sense that locking up some prisoners -- first-time drug offenders, for instance -- may be draining state money needlessly. The increased emphasis on rehabilitating prisoners and easing their return to society that President Bush advocated in his recent State of the Union speech makes sense to many of them.

But they also know that the strengthening of sentencing laws in the early 1990s, the prison-building boom (search) that began in that decade and efforts by prosecutors and lawmakers to take dangerous criminals off the street and keep them off has paid handsome dividends.

The prison population in America has quadruped since 1980 to more than 2 million people. Crime rates during the decade dropped to all-time lows. Coincidence? Consider that researchers have found that 15 crimes are committed for every person released from prison, and that 17 crimes are avoided for every person put into prison. Also along those lines, a 10 percent increase in prison population leads to a 13 percent decrease in homicides.

Considering that half the people in America's prisons are serving time for violent crimes, that means that, conservatively, millions of people have avoided becoming victims of such crimes thanks to these policies.

So pardon them if they're not quick to slash corrections budgets when corrections makes up so small a part of states' operational expenditures--about 6.7 percent, according to the latest research. Pardon their skepticism of a rehabilitation system with a long, miserable record of failure -- two-thirds of those released from prison this year will be re-arrested within three years and almost 49 percent of the violent criminals released will return to prison in that time period.

There is a lot of discussion in the country these days about the proper role and size of government. But all agree that providing for the public safety is its first and foremost job.

Right now, that means operating and building prisons will remain for some time to come a significant priority of government. America's state prisons operate today at up to 117 percent capacity, which means two things: we must ensure we incarcerate only those who truly should be in prison, and we must face the fact that we need more prisons, not fewer.

States can save money by more effectively prioritizing within their criminal-justice systems. They can find alternatives for first-time drug offenders and others who haven't committed violent crimes. They can bolster vocational training, which shows some promise of better preparing prisoners to find employment after release.

But there's only so much that can be done. America faced a real problem when the prison-building and sentence-strengthening movements began -- a wave of violent crime that left much of the nation gripped in fear. This problem got better in the 1990s, but it hasn't gone away. And even if we can decrease recidivism, those who commit crimes, especially violent crimes, owe a debt to society and need to do their time.

In truth, America does not love prisons. We'd far rather neither have nor need them. But some of us clearly need to be in prison for the safety of the rest of us. As long as that's the case, we can, will and, indeed, must spend the money to do what it takes to incarcerate those people. Which means that breaking up with the tough law enforcement of the 1990s will be indeed be hard to do.

David Muhlhausen is a senior policy analyst in the Center for Data Analysis at  The Heritage Foundation.