The last few years have been very good for the once-beleaguered post of big-city mayor. While the federal government has been engaged in a decade of trench warfare, the reform currents in American life have flowed through city hall. School, welfare and crime reform all have a downtown address.

Being a big-city mayor seems like one of the best jobs in politics these days. Mayors are, by and large, winning popular acclaim. One notable exception is San Francisco's incumbent, Democrat Willie Brown, and his example is telling. Brown has violated the new commandment of mayoral politics: Thou shalt pay close attention to quality-of-life issues. Mayor Brown, whose hauteur has led him to be called "Emperor Brown," warned constituents before he was elected that "street lights, dog-doo and parking meters are not my cup of tea." When San Francisco residents discovered what this meant in practice--only intermittent attention to the problems of homelessness and panhandling, for example--Brown's popularity plunged.

These days the success--and popularity--of mayors lies in involving local citizens and local business people in solving local problems. That's not an option available to national politicians. Despite the seemingly intractable nature of many urban problems, from poverty to poor schools, the message of the past few years is that, in big cities, mayors really can make a difference. The question is whether such optimism is justified.

It's certainly a contrast from a decade ago when cities were seen as ungovernable and mayors were being thrown onto the slag heap of American politics. In the late '80s and early '90s, sections of Detroit had returned to prairie and Philadelphia was on the edge of an economic meltdown; in D.C. the high murder rate and sluggish economy, along with the antics of Mayor Marion Barry, were confirming every suburban criticism of the cities. In New York City, Democrat David Dinkins's disastrous administration imposed billion-dollar tax increases during a recession and 330,000 people employed in the city lost their jobs, while a drug-runners' riot in Washington Heights, an antisemitic rampage in Brooklyn's Crown Heights and a record-high murder rate mocked the rule of law. In Los Angeles, the once-successful administration of Democrat Tom Bradley was shattered by the 1992 riots, which set off smaller civil disturbances in Seattle, Las Vegas and Atlanta.

Mistakenly thinking it could convert misery into money, the U.S. Conference of Mayors, the leading organization of big-city mayors, saw a golden opportunity in those riots. The mayors, said Milwaukee's John O. Norquist (D), thought that "the federal government would realize it had to do something for cities." Kurt Schmoke (D) of Baltimore warned that while "we don't want to have to burn down our own cities," more riots were inevitable unless more money was forthcoming from the federal government.

Such was the prevailing attitude when President Clinton took office, and Dinkins handed him a 24-page wish list of everything from infrastructure projects to subsidized vouchers that would allow low-income families to attend cultural events. But after 30 years of suburban economic growth and substantially self-inflicted urban decline, the cities had lost their clout in both the country and in Congress. The first Clinton budget crashed, bringing to an end the period, begun after the violence of the '60s, in which the primary federal urban policy consisted of buying riot insurance.

It took a new set of faces and an abrupt change of focus to change all that. Instead of trawling for dollars on Capitol Hill, the new breed of mayors--Richard Daley of Chicago, Ed Rendell of Philadelphia and Norquist, among them--began looking for local solutions. And these Democrats were quickly joined by the unexpected 1993 victories of Republicans Rudolph W. Giuliani in New York and Richard Riordan in Los Angeles.

The first big success of urban policy in 30 years came in New York City even before the economic upturn when Giuliani and his police chief, William Bratton, showed how "broken-windows policing"--addressing the small problems to prevent major crimes from following--could dramatically reduce the crime rate even as the police use of force dropped sharply.

The new mayors' targets were ambitious. Instead of waiting for the federal government while middle-class blacks and whites were heading for the exits, they seized the reins of education reform. The Chicago-to-Milwaukee corridor took the lead. In Chicago, Daley cut a deal with the Republicans who were running the state government to take direct mayoral control of the city schools. In Milwaukee, Norquist took heat from his own party and from public-sector unions by pushing for school choice, including vouchers. While one approach involved centralization and the other decentralization, what they had in common was that both looked to break the hold of the public-sector monopoly by introducing accountability into education. Subsequently Detroit and Boston have moved toward the Chicago model, while Cleveland has tried to emulate Milwaukee.

Similarly, in Indianapolis, Republican Stephen Goldsmith demonstrated how city services could be improved and union jobs upgraded by opening vehicle repair and waste-water treatment to competitive bidding between the public and private sectors. Four thousand local officials have visited Indianapolis to study Goldsmith's approach; they're part of what he calls "the cross-party cross-fertilization of new ideas" that has helped revive the cities. The idea was to work hard on the issues that most immediately affected the daily lives of city residents.

The mayors who have not adopted these have heard about it. In Baltimore, for instance, Schmoke came under fire from candidates who campaigned to succeed him for refusing to champion the Bratton-style policing policies that were working in New York, Philadelphia and New Orleans. His likely successor, Martin O'Malley, won the Democratic primary by promising to reverse Schmoke's policies.

There's another way of looking at this transformation: The new mayors' "back-to-basics" approach to city government was born of necessity. Unless they could both improve services and keep taxes under control, the moving vans would continue to drive in only one direction. Their emphasis on quality-of-life issues led to an almost obsessive concern with the details of daily living. Daley has been planting trees throughout Chicago, even on the roof of City Hall. Giuliani has cracked down on everything from jaywalking to drunk driving--and lived politically to tell the tale. Properly managed, the cities' strong suit, Norquist argues, is their design and public spaces. Cities, he notes, offer the pleasures of public life unavailable in suburbs where "life is filtered through a two-screen experience--the TV and the windshield."

The focus on detail is a return to the traditional task of mayors who, by the very nature of their job, are unlike governors or members of Congress. Mayors are in constant touch with their constituents; they are by definition local personalities, and recent success stories have fueled that image. Rendell certainly has a mixed record as mayor of Philadelphia, but no one doubts that his hail-fellow-well-met style has raised the spirits of that city. If Rendell's exuberance has obscured policy failures, in New York, Giuliani's hard-edged, take-no-prisoners style has served to obscure his policy achievements.

That's not to suggest that being a mayor is a real political steppingstone. Despite the success of the new mayors, city hall remains a weak jumping-off point for higher office. Goldsmith was defeated in his race for governor, and Norquist and Rendell, the incoming chairman of the Democratic National Committee, have been thwarted in their statewide aspirations. If Giuliani wins his Senate race against Hillary Clinton, he would be the exception. But no mayor of the Big Apple has gone on to higher office in the 20th century.

Still, even without winning higher office, the new wave of mayors has had a profound effect on national politics. When Texas Gov. George W. Bush recently described himself as a "compassionate conservative," he was following in the path of Riordan, Los Angeles's highly effective Republican mayor, who calls himself a "bleeding-heart conservative." Bush has made Goldsmith his chief domestic policy adviser. And Vice President Gore's commitment to quality-of-life issues sometimes sounds as if he's running to be the mayor of America.

This focus is a sweet reversal for city dwellers, of course. But the troubling question is how much of the new mayors' legacy will endure. Wellington Webb (D) of Denver, the new head of the U.S. Conference of Mayors, sees an unstoppable wave of reform. But there are reasons for doubt. The achievements of the past decade were made possible not by ongoing social movements, but by the conjunction of the perception that the cities were about to collapse with the presence of extraordinary leaders like Webb himself. Ironically, the possibility of ongoing reform may have passed with the ongoing prosperity of the late '90s.

What's more, the reform mayors lack heirs. Neither of the lackluster candidates in the campaign underway in Indianapolis looks like a promising prospect to fill Goldsmith's shoes. Riordan and Giuliani are due to leave office no later than 2001--and neither is likely to have much influence on his successor. The biggest immediate test for the future of reform regimes comes with the Philadelphia mayoral election on Nov. 2, where Democrat John Street and ex-Democrat Sam Katz are running to replace the term-limited Rendell.

The Philadelphia election is instructive because it is shaping up as a battle over the limits of reform. Street, who is running on Rendell's record, insists that little more can be done to reform Philly, even though its taxes are still the highest of any large city and it lost 150,000 residents in the 1990s. Without saying it, Street sees the reforms of the 1990s as a passing phase. Katz, by contrast, insists that Rendell's reforms are just the first phase of a larger transformation. He argues that, with good leadership, Philadelphia can remake itself into a player in the new economy. Building on the city's numerous universities and medical schools, Katz wants to use sharp tax cuts and school choice to attract the knowledge workers who are driving the economy. If Katz wins, urban reform may gain new energy and a new champion. If he loses, it may slowly wither on the vine. And, with that, the notion that mayors can really make a difference may well begin to evaporate.

Fred Siegel is a senior fellow at the Progressive Policy Institute and the author of "The Future Once Happened Here: New York, D.C., L.A. and the Fate of America's Big Cities" (Free Press).