The buzz around Newark's new mayor has been so intense that pundits are already speculating about his chances of becoming the nation's first black president. But first, Cory Booker has to prove he can change his city. And it's a city that's notoriously difficult to change.

In some highly visible respects, Newark did all right in the closing years of Sharpe James' 20-year mayoral tenure. The downtown enjoyed a fairly impressive revival, marked by thousands of new jobs and a successful performing arts center. There's a new minor-league ballpark, and ground recently was broken on a $310 million hockey arena. The easy victories, in other words, have already been won.

The problems left for Booker to deal with are thornier. Newark's social fabric has never really recovered from the deadly rioting in 1967 that left a legacy of gangs and violent crime, lousy schools, scary public housing and a quarter of the population living in poverty. Booker has promised to address all of these--but in so doing, he may have promised too much. He takes office at a time when the deficit-ridden state of New Jersey is contemplating reductions in aid to its big cities, and Newark will soon run out of money from a $450 million airport lease settlement that has helped smooth its recent budgets.

Booker talks about imitating Milwaukee's school-choice program, although he would like vouchers funded with private money rather than the city's. He wants to use a version of New York City's CompStat performance measurement program to bolster a troubled police department. But it isn't just the police force whose management needs an overhaul. The entire city bureaucracy has a reputation for being resistant to change.

To judge by his press clips, the 37-year-old Booker should be up to any challenge. Raised in an affluent Bergen County suburb, he was a high school All-American in football and attended Stanford on a scholarship. He was a Rhodes Scholar at Oxford, where he read Gandhi and became a vegetarian. He has a law degree from Yale.

Booker moved to Newark specifically because it was distressed, once explaining that it was "a calling, not a choice." He unseated a veteran city councilman and then set his sights on defeating James. Booker's 2002 mayoral campaign garnered national media attention--it was the subject of "Street Fight," an Oscar-nominated documentary--but he was unable to match James' machine-style strength on the ground or refute the charge that he was too pedigreed for a poor city.

Booker spent the next four years building an organization and a polling lead that scared James out of the race. He also lent his prestige and a good deal of money to the "Booker team," a slate of council candidates who won all nine seats this spring.

But even with a friendly city council, the mayor has his work cut out for him. In the words of Walter Fields, former political director of the New Jersey NAACP and a longtime observer of Newark and its problems, Booker needs to convince people that change requires some pain, and that for all his charisma and connections, he can't just wave a magic wand and make the city better overnight.