You and I might not agree on the best American governors of recent years, but we would probably agree on what makes a governor effective. Mostly, it's a matter of having a coherent program and finding ways to get it enacted. Similarly, it's not too hard to define the qualities of an outstanding legislator. This is somebody with the brains to understand complex problems, the creativity to frame solutions, and the personal skill to build majorities in favor of the things he proposes. However people may differ on the elements of wise policy, they tend toward consensus on who's good at getting the job done.

But broaden the subject of the inquiry from individuals to institutions, and the consensus all but disappears. What's a good legislature? For that matter, what's an effective one? That's about as slippery a question as you can find anywhere in the textbooks of political science. Those who believe in tax reduction and limited government tend to think the Republican-managed state legislatures of the past decade have generally acted in the public interest. Those more interested in maintaining high levels of social service spending come to an opposite conclusion. At the institutional level, good performance is very difficult to disentangle from ideology.

But if students of legislative life have been a little bit befuddled in their search for the good, they have historically been rather confident that at least they knew a really bad legislature when they saw one. A bad legislature is unable to attract talented members, is lacking in staff and resources, succumbs to the pressures and personal favors of lobbyists, meets only infrequently and allows the governor to treat it like a doormat. A bad legislature is one pretty much like those found in most American states in the 1950s and '60s.

It was in the late 1960s that the Ford Foundation, subscribing to this view, funded one of the most influential crusades in modern American government--to improve the quality of state legislative practice. Over a period of several years, Ford subsidized a long series of detailed reports, a widely circulated paperback book, called "The Sometime Governments," and a much-publicized ranking of every legislature in the country, from 1st to 50th, on categories labeled functionality, accountability, informedness, independence and representativeness. The majority of legislatures did poorly in virtually every one of the categories.

There was, however, one shining model for states to copy. It was California, which under the leadership of Speaker Jesse Unruh had transformed itself from corruption and ineptness--"I am the governor of the legislature," liquor lobbyist Artie Samish had proclaimed just a few years earlier--into a condition of admirable capability. California's legislature, researchers reported, was stocked with talent, impressively staffed, resistant to old-fashioned lobbying pressures and strong enough to challenge governors.

And so, backed by mountains of surveys and scholarly research, legislatures throughout the country began to reposition themselves in the direction of Sacramento. They sought to professionalize. Not all of them moved equally far in this direction, of course--some small states scarcely moved at all--but on balance, it is fair to say that state legislatures transformed themselves dramatically in a relatively short period of time.

Three decades after the reform project completed its work, there is no question that state legislatures as an institution possess more resources, more information and a higher degree of independence than virtually any of them did in the bad-old pre-reform days. But are they better? That remains an elusive question.

Its elusiveness can be demonstrated by a brief look at two of the states that took reform most seriously. Both Minnesota and Wisconsin moved expeditiously from part-time, poorly staffed institutions to ones that remain in session for a good part of the year and provide members with abundant personal and informational support. For a decade or so, this looked like a highly positive development. More recently, it hasn't looked so good.

In the 1990s, the Minnesota and Wisconsin legislatures fell into a culture of partisanship and incivility that made it difficult for them to handle the most basic governmental tasks. By the end of the decade, voter disgust with the infighting among Democrats and Republicans in Minnesota helped contribute to the upset gubernatorial victory of third-party insurgent Jesse Ventura. But the situation didn't change during Ventura's four years in office, and it hasn't changed since his departure. This year, partisan bickering was so intense in Minnesota that lawmakers adjourned in May without coming close to passing a budget, and the House Speaker declared the session the least productive of his 25-year career.

Wisconsin's legislature, with a century-long tradition of honest politics and public-spirited reform measures, professionalized to the point where the two parties became electoral war machines willing to go to virtually any lengths in the battle for control. Leaders became consumed with campaigns and fund-raising. As I write this, half a dozen longtime members, including the former Speaker and the former Senate majority leader, are under indictment on charges that range from extorting contributions to misusing state funds for political purposes.

Meanwhile, the legislature in California, so recently a model for what such bodies ought to be like, has become a model for what they should not be like. Famously unable to take any serious action against the state's multibillion-dollar budget shortfall, it has largely abdicated its fiscal authority to Governor Arnold Schwarzenegger, whose fulminations against legislative politics were in part responsible for his election last fall.

What are we to make of all this? Not that professionalization was a mistake, I think, but simply that legislatures can fail in more than one way. The poorly equipped, lobbyist-dominated institutions of the 1960s were inadequate and needed to change; the reforms of the 1970s largely took care of that. But solving one set of problems doesn't preclude the emergence of new ones. A cynic might simply say that all we've managed to do over the past 30 years is trade one kind of "bad" legislature for another.

Alan Rosenthal, who may know more about American legislatures than anyone, doesn't take the cynical position. Rosenthal was involved in the reform efforts of the 1970s as a young political scientist and has been studying the legislative process ever since. He has spent much of his time stalking state capitol corridors, buttonholing the members and the lobbyists, forging personal relationships with the leaders. Through all those years, half a dozen scholarly books and countless essays, he has pondered not only the negative side of the issue--How do legislatures get in trouble?--but also the opposite and much more difficult side: What makes a good legislature?

Rosenthal's newest book, "Heavy Lifting: The Job of the American Legislature," is in large measure an effort to sum up his life work by answering the latter question. He starts by citing a couple of criteria that, in his view, shouldn't be used to determine whether a legislature is good or not.

One is the product. That's a matter of political values and personal taste. I might think a legislature that grows the state budget is a model of performance. I have a right to my opinion. But you have a right to the opposite opinion. As Rosenthal says, "it's probably not possible to agree on a product that is indispensable to a 'good' legislature. It may not even be worth the search."

Then there's structure. The legislatures of the 1960s lacked the staff, physical facilities and communications apparatus to serve the public interest. But, as the past two decades have shown, all the equipment in the world doesn't guarantee virtue. The essence of a "good" legislature lies somewhere else.

At that point, Rosenthal suspends the inquiry and takes the reader on a 200-page discursive tour of legislatures and leaders he has known, especially those he has watched in recent years. When the tour is over, he does his best to answer the question. Legislative excellence is all about balance and harmony. There are three major functions of the modern legislature: representation, lawmaking and dealing with the executive branch. The ideal legislature does all of them well, and keeps them in proper proportion. Currently, Rosenthal argues, legislatures are performing the representative function extremely well. Members are listening to constituents, and solving people's problems. The lawmaking function isn't quite as strong, and the executive-relations function is the weakest of the three.

It's nice and symmetrical, anyway. It almost sounds like Plato's Republic. Does it have any practical value? Actually, it does have some. If the lawmaking side needs improvement, it might be a good idea to increase the power of the committee system. Committees are where most lawmaking actually gets done. If legislatures are finding themselves overmatched by governors, one might want to reexamine term limits. Term limits have deprived legislative bodies of the senior members who can wrestle with the executive on an equal basis. And when leaders come and go every couple of years, nobody has sufficient clout to keep the fragile components of the institution in sufficient balance.

I confess that, even when I had finished reading about life in Rosenthal's Republic, I still didn't have a clear idea of what a "good" legislature would look like up close. Quite likely I never will. But then, on this subject as with many fields of inquiry, it may not be the answers that matter most. What's important is that we keep asking the questions. Judged by that standard, Alan Rosenthal has performed an admirable service to American government.