Money mattered in Michael Bloomberg's case.

The billionaire's personal fortune (ranked 10th in the nation by Fortune) allowed him to bankroll his three runs for New York City mayor, freeing him to hire people he believed were the best and the brightest, rather than friends of donors.

His philanthropy also backed up the experiments he ran at City Hall — and allowed him to encourage other mayors to take similar tacks.

"It's the first time we've had a foundation specifically interested in mayors and administrations that can be innovative, and put an initiative behind that," says Greg Fischer, the mayor of Louisville, one of several cities that have won grants from Bloomberg Philanthropies.

Bloomberg, who is stepping down Jan. 1, has already announced that he will continue offering both money and technical assistance to mayors around the nation and around the globe.

"One of the places where he's been most influential is his theory of mayors being key agents of change," says Carol Coletta, vice president of community and national initiatives for the Knight Foundation.

It's not only his wealth that has made Bloomberg stand out. Any mayor of New York, the nation's biggest city and its media capital, is certain to receive outsized attention for his efforts.

But Bloomberg has been an exceptionally innovative mayor. And many of the changes he has pursued in his city — in education and transportation, in public health and public spaces — have been imitated and adapted in dozens, if not hundreds, of other cities.

"He's the most influential mayor of the first decade and a half of the 21st century," says Bruce Katz, who directs the Metropolitan Policy Program at the Brookings Institution.

Nanny-State Leader

For all his urban policy initiatives, Bloomberg will always be associated with public health programs.

Many people view his efforts to curb smoking, salt intake and especially supersized sodas as the height of nanny-state arrogance — a local government official overreaching to prevent people from doing harm to themselves. And his effort to spread gun control beyond New York's borders, through his own campaign donations, has suffered several setbacks.

Much of what Bloomberg did in this area, however, is affecting diet and health across the country. His ban on trans fats from bakeries and restaurants was quickly imitated elsewhere. Once places like California got on board, national restaurant chains altered their recipes.

Something similar happened with calorie counts on menus. Seattle, Philadelphia and cities and counties in California followed New York's lead, leading the restaurant industry to push for a uniform federal standard.

"He used his city and his health department to push through some major reforms that are beneficial to New York City and set a tremendous example that people around the country have emulated," says Michael Jacobson, executive director of the Center for Science in the Public Interest, a nutrition advocacy group.

In promoting his ideas on the national stage, Bloomberg has been aided by having his former health commissioner, Thomas Frieden, serving as head of the federal Centers for Disease Control — one of several well-placed former Bloomberg staffers in the Obama administration, including HUD Secretary Shaun Donovan.

Armed With A Plan

But Bloomberg concentrated on reshaping his city and others from the ground up. Recognizing that New York was bound to absorb perhaps a million more people over the next generation, Bloomberg crafted long-range plans for New York that have since been widely copied elsewhere.

"It's really important to look not just at the daily work of your city, but what your city should look like in 10 or 20 years," says Fischer, the Louisville mayor.

Bloomberg's exercise wasn't just catnip for the urban planning set but also was readily evident to residents and even to tourists (whose numbers have increased some 40 percent during his time in office).

Many areas of an already crowded city grew more dense, while cars were banned from parts of Times Square. An old freight rail line along the West Side of Manhattan became an enormously popular park known as the High Line — one of many new parks built under Bloomberg.

"He deserves credit for grasping very early that people want to walk to work, bike, have better mass transit," says Nicole Gelinas, a fellow at the Manhattan Institute, a think tank.

Steering Through Shocks

The primary date for Bloomberg's first run was originally set for Sept. 11, 2001. His predecessor, Rudolph Giuliani, became a national hero for his response to the terrorist attacks that day.

Giuliani had already shown that New York not only was governable but could be made safer. But Bloomberg had to deal with the long aftermath of the attacks. He has since guided New York through other major shocks — the near collapse of Wall Street in 2008 and the effects of Superstorm Sandy last year.

"Just this year, the resilience plan again leads the country," says Armando Carbonell, planning chairman for the Lincoln Institute of Land Policy. "It wasn't a sort of big, aspirational plan — it was concrete, taking into account climate in looking at air quality, recycling and transportation systems."

What Bloomberg grasped when he took office — a time when many predicted New York and Wall Street would head into decline — was that central cities were becoming much more desirable places to live.

Most cities are trying to turn their downtowns into 24/7 nodes of activity, but Bloomberg came up with ways of doing that which are being adapted all over the country.

Bloomberg also changed the way the city did business with small business and helped recruit universities and other players to boost scientific research and industry in New York.

"He converted the city into a magnet for talent," says Katz, the Brookings scholar. "There was no tech sector in New York, really, but it's now thriving, with huge effects."

The Power Of Policy

Bloomberg has also altered the way mayors run their own offices, with everything from doorless bullpens at city halls to 311 calls linking citizens more easily to government. He made it fashionable for mayors to take over direct control of schools and made it imperative that city administrations take data into account in their decision-making.

Not everyone believes some of Bloomberg's widely touted innovations, such as pedestrian plazas and bike-sharing lanes, answered the most pressing needs of the city. Bloomberg couldn't eradicate New York's own financial problems, with pensions eating up nearly twice as great a share of the city budget as when he took office.

He also conveyed to some the impression that he focused on Manhattan at the expense of other boroughs. It's one reason his successor, Bill de Blasio, found his message of income inequality to be so resonant in a city Bloomberg himself once described as a "luxury product."

Still, Bloomberg has had an enormous effect not only on his own city but also on how mayors everywhere approach their jobs.

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