JIM KENNEY, a progressive with union support and backing from black leaders, handily won the Democratic Party’s nomination in Philadelphia’s mayoral primary on May 19th. Because Democrats outnumber Republicans by seven to one, he will probably win the general election in November. Mr Kenney wants to raise the minimum wage, end stop-and-frisk police procedures and bring in universal pre-kindergarten—in short, do most of the things outlined recently by New York’s Democratic mayor, Bill de Blasio, in his new agenda for the left. He has said he will build on the positives of Michael Nutter, a fellow Democrat who is stepping down because of term limits. Given Mr Kenney’s politics, that will be quite a challenge.

When Mr Nutter took office in 2008 he swore, unusually, the Athenian oath, and had it printed on the back of his business card. It includes a promise not to disgrace the city: no small vow in a place then plagued with corruption. To that end, Mr Nutter set up an office of integrity and re-established an independent inspector-general, a government watchdog with teeth. Nepotism and accepting gifts were forbidden by executive order. The new mayor also promised to make Philadelphia “greater and more beautiful”. Parts of the city do seem to aspire to that, particularly Centre City and the waterfront. Cranes strut on the skyline, and plans for new development are springing up on all sides.

Mr Nutter has been a steady hand at the city’s helm. An unassuming, slightly nerdy fellow, he is neither rich nor part of the political machine. He has a tendency to nanny, lecturing Philadelphians constantly on guns, obesity and recycling their rubbish. But he is clever, understands numbers and uses common sense. Shortly after he took office, the recession hit. He made politically tricky decisions (cutting the pay of non-union city workers, raising the sales tax, but avoiding layoffs), which ultimately helped Philadelphia stay afloat. Only just, though: although its wage taxes are among the highest of any big American city, and businesses are taxed both on gross receipts and net income, it is able to fund less than half of its $10 billion in pension obligations, a bind exceeded only by hopelessly-in-debt Chicago.

In a place once nicknamed “Killadelphia”, one of Mr Nutter’s promises was to reduce the number of murders. Today crime is at its lowest levels since 1971, and the homicide rate has fallen by more than a third since he took office. This is partly because of demographics, but also the result of community-policing methods that have drawn national attention (the city’s police commissioner chairs the White House task-force on the subject).

The mayor has also invested heavily in schools, in part to compensate for severe cuts in state funding, and controversially supported the School Reform Commission’s decisions to close bad schools down. High-school graduation rates have risen from 52% to 65% since he came in, though they are still well below state and national levels.

After decades when manufacturing jobs left the city, Philadelphia is at last seeing some job growth, but it is a long way from where it should be. (Businesses don’t care for that double taxation.) More jobs are needed because the population is growing too, after decades of decline. Immigrants are pushing in and young people are staying put: Philadelphia has the fastest-growing population of Millennials (18- to 30-year-olds) of any big city.

Bruce Katz of the Brookings Institution, a think-tank, says Philadelphia should “supercharge its economy” by creating an innovation district around the 30th Street station, the city’s main railway terminal. The station is close to Drexel University, University City Science Centre and the University of Pennsylvania. These three institutions, among others, are investing in the area, bringing in new houses and shops as well as creating space for incubators and research. Drexel has also bought a closed-down high school, and means to turn it into labs, flats, shops and an elementary school. After that it has designs on redeveloping 85 acres of railway tracks and yards.

“Nutter really made a lot of this work,” says John Fry, the head of Drexel University; the mayor helped not with money, since he had none, but with zoning permissions and the strong backing of City Hall at every stage. The question now is whether Mr Kenney, with his very different priorities, will carry that enthusiasm on—and whether he will dare take on the problems, especially taxes and pensions, that even Mr Nutter could not solve.