NEWARK, N.J. – Four years ago, Cory Booker’s campaign for mayor of this city, New Jersey’s largest, attracted from Manhattan lots of press attention, dollars, and idealistic young volunteers – but ended in a narrow loss to the incumbent.

Now, Mr. Booker, a 36-year-old graduate of Stanford and Yale Law School and a Rhodes Scholar, is at it again, gearing up for another run.

The hot water in his apartment in the Brick Towers housing project stopped working earlier this week, just as a snowstorm dumped more than 2 feet of snow on the East Coast. But the sacrifice could be worth it if it helps Mr. Booker defeat efforts to depict him as an outsider in this city.

Mr. Booker is the native of an affluent suburb in northern New Jersey. For the past eight years, though, he has called Newark’s low-income Central Ward home.

Last time around, Mr. Booker lost to Sharpe James, who is now in his fifth term. This time, Mr. Booker has wooed several members of his opponent’s inner circle to his campaign and picked off a number of key supporters.

If Mr. James, 69, decides to run, as he is widely expected to, some political analysts said the rematch will be closer than the 3,500 votes that decided the last election. That campaign was the subject of the Oscar-nominated documentary “Street Fight” and drew national attention when a political war erupted between the two black candidates – Mr. Booker, the younger, fresh faced reformer, who emerged with celebrity status, and Mr. James, who had stalwart machine backing and a presence in local politics for decades.

“Unlike the last campaign, it’s not who we’re running against, it’s what we’re running for,” Mr. Booker said during an interview in his 21st floor office, located in the center of Newark’s downtown.

On Mr. James’s watch, downtown Newark has seen some revitalization, but not far away, in the rest of the city, the schools are among the worst in the state and poverty and crime are serious problems.

Mr. Booker’s attempt to dislodge the political infrastructure in Newark – a city that has floundered since the race riots of the 1960s and has garnered a reputation for political corruption – led to a Howard Dean-style upstart campaign four years ago, even before Dr. Dean’s presidential bid got under way.

For the last four years, Mr. Booker, who is 6 feet 3 inches tall and was an all-American football player, has been running a non-profit he founded called Newark Now. His backers are hoping that his commitment to Newark, even after losing in 2002, will shift the outcome this time around.

“We pretty much had every union in the state against us last time and now as we sit down with the unions, more and more of them are committing their support to us,” Mr. Booker said. “It’s really great and encouraging.”

Mr. Booker, who has already raised roughly $3.7 million, has an odd mix of support. He has received contributions from celebrities such as Oprah Winfrey, Chris Rock, and Ben Affleck, while also making inroads with high-profile Democrats and conservatives who are drawn to his support for school choice and his willingness to work with the private sector.

“He’s certainly demonstrated over the past six, or seven, or eight years that he’s willing to roll up his sleeves and live and work in the community,” the founder and CEO of the Democratic Leadership Council, Al From, said. “I would guess that the fact that he’s worked there and stayed there will make more people comfortable with the kind of change that he will bring.”

But some called the national attention and the interest from young, well educated Manhattanites, who worked on Mr. Booker’s campaign and helped to pad his war chest, a double-edged sword.

A political analyst in New Jersey, Steve Adubato Jr., said drawing people into Newark politics that were not paying attention before 2002 has been both positive and negative for Mr. Booker.

It has gotten people interested in improving a city, but has allowed Mr. Booker’s opponents to feed the perception that’s he’s using Newark as a launching pad.

“I think everyone I know in Montclair is supporting Cory Booker, there are parties for Cory up here,” Mr. Adubato said. “I’ve never seen anything like that. Maybe in New York it’s no big deal, but in Newark sometimes it feeds the perception that you’re not a real Newarker. If I were Cory I would do that exact same thing, because there is not a lot of money in this city.”

Mr. Booker said all the staff members on his campaign this time around are Newark residents and he is raising money both inside and outside the city: “The reality is that we got 25,000 votes in the last election so this outsider stuff really didn’t stick. We got more votes losing to Sharpe James than he had gotten in his three previous elections,” he said.

One of Mr. James’s backers in the last election, the Reverend Al Sharpton, told The New York Sun this week that he hadn’t yet decided whom to back or whether to get involved this time around, leaving open the possibility that he could switch allegiances.

“In the last two or three years I have gotten to know Cory better. I have not decided what I’m doing. I would not make that decision until I know what the mayor is doing,” Rev. Sharpton said.

Mr. James’s office did not return calls for comment, but the mayor, who also holds a job as a state senator, has never lost an election.

Mr. Adubato said he expected Mr. James to wait until mid-March, the deadline, to announce whether he’ll run and said the mayor can’t be underestimated.

“This campaign is going to start for real March 17,” Mr. Adubato said. “If the mayor doesn’t run, it’s Cory’s to lose. If the mayor does run, it’s just a war and a dogfight every inch of the way.”