Standing at the balcony of the Water Works restaurant on a gorgeous afternoon Thursday, Democratic mayoral candidate Michael Nutter had plenty of reasons to smile.

While he waited for a news conference to accept the endorsement of two grassroots groups, a stranger, Kathleen Sucharski, interrupted her lunch to shake Nutter's hand. "I just love you," she said.

Better, she introduced her mother, Loretta, celebrating her 72nd birthday, who beamed as Nutter signed her birthday card.

In a city with a history of racially charged elections, an elderly white woman from Northeast Philadelphia embracing this African-American politician was a good omen, one of several that day for Nutter.

Moments earlier, word had broken that the Daily News had joined the chorus of Nutter media endorsements. Those, along with Nutter's strong showing in fundraising and two recent polls, have made him what he wants to be: a potential winner.

Which raises a question more people are now considering seriously: Does Mike Nutter have the leadership skills to be an effective mayor?

In 15 years on City Council, Nutter has amassed an impressive record of legislative accomplishment, including a smoking ban and some of the most far-reaching ethics reforms in the nation.

He's known for long hours and hard work. He has a reputation for intelligence, honesty and persistence, and has long been a favorite of good-government policy wonks.

He's a competent, if not inspiring, public speaker.

If there's a question about Nutter's ability to lead, it's whether he has the political skill and temperament to handle the demands of the mayor's office.

Nutter was elected to Council in 1991, taking the district that includes Roxborough, Manayunk, East Falls and parts of West Philadelphia from incumbent Ann Land on his second try.

He ran as a reformer, and announced upon being sworn in that he wouldn't accept the free Crown Victoria that taxpayers provide to Council members, choosing to drive his own car to work.

It was a sign of things to come: Nutter would walk the walk of reform and do things his own way. And if it showed-up colleagues who were happy to accept their luxury cars, so be it.

By nearly all accounts, Nutter represented his diverse district well, and it rewarded him with easy re-elections. In Council, he soon proved himself a leader on issues of citywide impact.

He led the drive to establish the Police Advisory Commission, overcoming the opposition of Mayor Rendell. He sponsored a charter amendment to increase the mayor's authority over the school board (a move rendered moot by the state takeover of the schools).

He sponsored legislation requiring publicly funded construction projects to use workers who live in the city, and along with Councilman Frank DiCicco, he led fights to establish the Tax Reform Commission and reduce wage and business taxes. He led the push for the city's new voting machines.

In recent years, he led budget fights to increase funding for the Community College of Philadelphia and street-tree maintenance, and to hire an additional 100 police officers.

And most recently he sponsored and successfully passed a broad range of ethics laws called some of the best in the nation by Public Citizen, a watchdog group that monitors pay-to-play legislation across the country.

"He always amazed me, with his management skills, how much he could get done with a small staff," said Republican Councilman Frank Rizzo. "He really knew how to use the Law Department and other city agencies to get things done."

So what's not to like in Mike?

The edge in his style and personality, say some insiders watching the mayor's race unfold.

A mayor has to work with Republicans and Democrats in Harrisburg, Washington and on Council, not to mention labor, community and ward leaders. Relationships matter.

Gov. Rendell has said that a key to success as mayor is subordinating one's ego, flattering others and sharing credit.

Nutter wasn't known for that in Council. Though he shows a sense of humor and can be pleasant company, his game face is often intense and hard-driven.

Always willing to display his mastery of information or nit-pick a policy issue, he wasn't known for schmoozing to get that last vote or co-sponsorship.

Not a single one of Nutter's Democratic colleagues endorsed him for mayor.

"He's intense, but we're in an intense business," said Rizzo.

Asked if he has a problem working with people, Nutter smiled and said, "Look at my record. I've never passed a bill by myself. I've only got one vote."

He recalled working to get the late Republican Thacher Longstreth to give him the final vote he needed to override Mayor Rendell's veto of the Police Advisory Commission legislation.

"Am I hard-charging? Absolutely," Nutter continued. "Will I compromise? Absolutely, unless it destroys the integrity of what we're trying to accomplish."

He then offered a long list of compromises he made on business taxes, smoking regulations and other issues.

"I believe in collaboration and getting things done," Nutter said, "but I have a sense of urgency about me that I think makes people feel pushed before they're ready." Nutter said he hasn't asked any of his Council colleagues for a mayoral endorsement, because they're running for re-election and all have relationships with other candidates in the mayor's race.

"Why would I put them in an awkward position?" Nutter said. "It becomes so complicated for them. Council members all want to be on mayoral ballots and never want to endorse mayoral candidates."

Nutter's squeaky-clean image is not without a blemish, either. Last fall the Inquirer revealed he'd been working since August for Econsult Corp., a consulting firm that City Council had hired at Nutter's recommendation in 2004.

The job didn't violate any law or ethics rule, but Nutter took some criticism for not revealing it right away. He left the firm Oct. 31. When he released his tax returns earlier this year, they showed he'd earned $27,000 for the work.

Those who question Nutter's political judgment point to the letter he sent ward leaders last year criticizing the decision to call a special election that would effectively grant Nutter's Council seat to ward leader Carol Campbell.

Campbell, who had supported Nutter in Council elections, complained that Nutter blind-sided her with the letter and said it showed him "void of integrity, void of character, and honor."

Nutter could have remained silent on the issue of a special election. Why would he go out of his way to make an enemy he didn't need?

"Believe it or not, I did that because it was the right thing to do," Nutter said. And perhaps, there was a political logic to it. In stepping into the fray, he kept the respect of constituents who were angry about Campbell's selection. And he probably lost nothing, since Campbell would have supported mayoral rival Bob Brady in any case.

Nutter said in an interview last week he understands that a mayor has to court and flatter people he might not have the highest regard for.

And those who hope he can learn new political skills may be encouraged by the disciplined, effective mayoral campaign he's run.

The screen-saver on Nutter's computer at his campaign office is a text-crawl, taken from the movie, "Million Dollar Baby." It was on a sign hanging in the training gym that Clint Eastwood's character ran.

It reads, "Winners are willing to do what losers don't."

"It tells you something you need to know about me," Nutter said. *