There is widespread agreement that our criminal justice system is in need of reform, if not comprehensive overhaul. But beyond easy generalizations, there are few clear ideas about what should be done.

What is clear is that the most egregious failings of the criminal justice system result from demands that it treat ills it is manifestly incapable of treating. Three of the most salient of these are substance abuse, mental illness and homelessness, but there are many others, including a universe of petty, nonviolent crimes.

The salient theme must be to free the criminal justice system from dealing with problems it is ill-equipped to deal with. The result would be a smaller, less expensive system focused on the issues it is well equipped to deal with: violent crime and violent offenders. Problems other than those would be directed elsewhere.

As the size and scope of the criminal justice system was gradually narrowed, we would need to scale up other institutions -- private and nonprofit as well as governmental ones -- to deal with the problems the criminal justice system would no longer handle. Many, perhaps most, of the institutions that would take on the those problems already exist, but they are mostly unconnected to each other and mostly smaller than they would need to be.

It is a given that we don't know exactly how to solve the issues of substance abuse, mental illness, homelessness and petty crime. Nor do we know what an optimal mix of institutions to address these problems would look like. We would have to learn from experience.

Such a transition would not be smooth or easy. There would be up-front costs. But over the long term the results would be highly efficacious in terms of our society's health and well-being. The end result would be cost-effective as well, in contrast to our present system.

Unfortunately, however, while the private sector is built on spending in the present for rewards in the future, the public sector is abysmal at this. It is almost impossible for elected officials to approve spending for rewards that are not immediate. It would take an extraordinary measure of goodwill, across political as well as institutional boundaries, to accomplish anything at all in the way of reformulating the criminal justice system.

On the positive side, however, everyone knows that it is waste of time to arrest and jail people for being inebriated, drug-addicted, mentally ill or homeless, or for committing petty crimes. Relatively small numbers of people are arrested over and over again for these and other minor offenses. We don't know what else to do. It is manifestly clear that we need to discover what that is and get about doing it.

It also is a plus that there would be no national, or even statewide, formulas. Our criminal justice system is a complicated mix of local, state and federal institutions, each with its own problems and priorities. So an overhauled criminal justice system would consist of combinations of programs and institutions reflective of local circumstances. As local circumstances changed, programs and institutions would change as well.

As a society we would have much to gain. Perhaps, just perhaps, the undeniable need to address these subjects could produce the political will to do so. The promise of long-term results as well as savings, coupled with the avoidance of new, powerful bureaucracies, might reduce the political obstacles to progress. Politicians across the political spectrum might even find it politically rewarding to launch and engage in such a long-term endeavor.

In the end, then, progress will require two things: top-down political and institutional leadership along with a citizenry that demands such progress. Given that the majority of people in our country have experienced, in their own families, aspects of the shortcomings of our current criminal justice system, it is just possible that such combinations could come together.

We have grown accustomed to our political differences making it impossible to accomplish much of anything at all, much less anything grand. But perhaps the grandness of what needs doing with our criminal justice system could be just the thing to make it possible.