PHILADELPHIA -- When Democratic Councilman Bill Peduto dropped his mayoral challenge to incumbent Luke Ravenstahl, it ensured a snooze-fest for the May 15 Pittsburgh primary.

But in the City of Brotherly Love and Cheese Steaks five -- count 'em FIVE -- heavyweight Democratic candidates are battling it out to see who will be mayor.

The contenders are sitting U.S. Reps. Chaka Fattah and Bob Brady, longtime state Rep. Dwight Evans, former City Councilman Michel Nutter, and wealthy businessman Tom Knox.

Mr. Brady, 62, has been in Congress since 1998 and has been chairman of the Philadelphia Democratic Party since 1986. He has strong ties to organized labor and is close to many Democratic officials in the region.

Mr. Evans, 53, has been a state legislator since 1980 and currently chairs the powerful House Appropriations Committee. He lost a bid for governor in 1994 and a previous bid for mayor in 1999.

Mr. Fattah, 50, has been in Congress since 1994. He'd previously served in the state House and then the state Senate. He is married to a prominent TV anchorwoman in Philadelphia and has strong ties to the current mayor, John Street.

Mr. Knox, 66, is a millionaire businessman who made his money in software, banking and health insurance. He's come out of nowhere since August to become a serious contender, thanks to sinking $4 million of his own money into a flood of TV ads.

Mr. Nutter, 49, was a councilman from 1991 to 2006, when he resigned to run for mayor. He's a graduate of the Wharton Business School and previously worked as an investment manager at Pryor Counts & Co., a leading minority-owned banking firm.

Two of Philadelphia's last three mayors have been black, and if there were just one black candidate in the race this year, he'd likely be the favorite. But with three black candidates -- Mr. Fattah, Mr. Nutter and Mr. Evans -- the black vote is likely to be split.

All five Democrats have a legitimate shot at winning, although recent polls, along with some local politicians, are now portraying the race as two-tiered, with Mr. Fattah, Mr. Knox and Mr. Brady in the top tier.

"They seem like the top three," said Nilda Ruiz, president of APM, a Hispanic neighborhood group that sponsored a candidates' forum last week.

Mr. Fattah had been ahead in recent polls, but a Philadelphia Daily News/Keystone Poll of 364 registered Democrats, which was released Thursday, showed Mr. Knox taking over the lead for the first time, at 24 percent.

He was followed by Mr. Fattah at 17 percent, Mr. Brady, 16 percent; Mr. Nutter, 12 percent; and Mr. Evans, 10 percent. But a large segment of Democrats, 21 percent, was still undecided and could hold the key to the outcome. The poll has a margin of error of 5 percent.

Obviously, this latest poll was good news for Mr. Knox, but it also buoyed Mr. Brady, who doubled his 8 percent showing from January. Mr. Knox went up slightly (from 22 percent in January), while Mr. Fattah fell 9 points from his 26 percent showing in January.

Interviewed before the APM forum last week, Mr. Fattah insisted he'll do well among African-Americans on May 15. The new poll supported that claim, showing him getting 25 percent of the black Democratic votes, the highest of the five hopefuls.

One factor that could hurt Mr. Fattah is his refusal to release his income tax records, something the other candidates have done. Local newspapers have made big headlines out of his refusal.

TV's role seen as decisive

Mr. Fattah said the rise of Mr. Knox in the polls isn't a big surprise, since he's spent at least $4 million of his own money on TV ads. Mr. Fattah said he hasn't spent anything on TV yet, but indicated he will soon do so. Mr. Brady has spent the second most on TV, about $1 million.

"This election is definitely a TV campaign," said G. Terry Madonna, director of the Keystone Poll at Franklin & Marshall College in Lancaster. "The folks who have run the most commercials are ahead."

When Mr. Knox entered the race in August, he was at virtual zero in the polls and few people took him seriously.

"It's apparent to us in the Philly TV market that Knox has pumped a lot of cash into his mass media operation," said Christopher Borick, a professor and pollster at Muhlenberg College in Allentown. "Four million dollars is a lot for a local race and it's buying him a lot of name recognition.''

Mr. Knox did take some flak last week when a protester dressed as "Tommy the Loan Shark" stood outside his Broad Street office and complained about a pay-day lending business he ran in the 1990s, which applied high interest rates to loans.

Because of the overwhelming Democratic registration advantage, winning the primary is tantamount to winning the election. And, barring some serious illness or political scandal, this year's winner most likely will run Philadelphia for the next eight years, starting in January. The current mayor, Democrat John Street, has served since 2000. Before him, Democrat Ed Rendell, who's now governor, served for eight years in the 1990s. And before him, Democrat Wilson Goode served for eight years.

The public dialogue has been refreshingly civil, with no personal or racial remarks among the candidates, Mr. Madonna said.

But there has been a fierce court battle over Mr. Brady's candidacy. Mr. Knox and Mr. Evans filed a suit seeking to knock him off the ballot because he neglected to include a city pension on his income form.

Initially, the Brady camp called it a "stupid'' but unintentional mistake, but later changed their stance and claimed there was no requirement to include the pension payment.

A judge from Luzerne County in northeast Pennsylvania was brought in to hear the case because of Mr. Brady's pervasive influence among Philadelphia politicians, including judges. He ruled that Mr. Brady could remain on the ballot, but the Knox and Evans camps are appealing to the Supreme Court. If the challenge is successful, it would leave Mr. Knox as the only white candidate on the ballot.

Despite Mr. Knox's lead in the new poll, some political observers caution that much could still change in the nearly six weeks remaining before the May 15 primary.

Mr. Borick said he still regards Mr. Fattah as the frontrunner because of his political experience and well-known name. "He knows how to win races in Philadelphia," Mr. Borick said.

Rendell staying clear
State Sen. Shirley Kitchen, D-Philadelphia, supports Mr. Evans, her colleague in Harrisburg, and noted that there is still a big bloc of undecided voters who could swing the race to him.

"Because of the record number of undecided voters, this race may be hard to call," she said. "Many people are waiting until the last minute to decide."

"Much of the electorate hasn't checked into the race yet," agreed Democratic consultant Larry Ceisler. "You're seeing a lot of undecideds. My hunch is that the support for the candidates is very soft" and could change.

All five candidates have appeared at numerous forums around the city -- not really debates, because they don't fire questions to each other. They speak and then take questions from an audience.

Gun violence often arises at the forums, because the city already has had 104 murders this year, compared to 86 in the same period in 2006. For all of last year there were 404 killings, which will be exceeded in 2007 if things don't change.

Mr. Evans is trying to restrict gun sales to one per month for individuals and to make the sale of certain types of weapons illegal. But action by the state Legislature is needed before Philadelphia (or any other city) can enact its own gun laws, and the Legislature has shown little interest in doing so.

Mr. Knox is promising to "hire 1,000 new police officers to stop crime," but critics question how he would pay for such a move, with the city facing chronic financial problems.

Mr. Brady, the city Democratic chairman, touts his ties to legislators in Harrisburg and said he'd go to the Capitol to get additional funds, including money for the city's financially strapped mass transit agency.

Improving public education, including the quality of city schools and the safety of students and teachers, is another issue. Mr. Nutter said that if he becomes mayor, he'd like to be responsible for running the schools, instead of a state panel and superintendent who now call the shots.

Mr. Rendell -- who remains hugely popular in Philadelphia -- is in a tough spot because he has close personal and political ties to all five candidates. He insists he's remaining neutral, but it hasn't stopped political observers from thinking he secretly favors one candidate or another.

Mr. Rendell said he has close ties to fund-raiser Herbert Vederman, who is helping Mr. Fattah. Kate Philips, Mr. Rendell's press secretary in Harrisburg, is now working for Mr. Brady.

"Over the course of my political career, Tom Knox has raised over $1 million for me. He paid for a poll for me [in 1991] showing I could win the Democratic mayoral primary. How can I be against him?'' Mr. Rendell said.

"And Bob Brady stood by me when I was running for governor in 2002 when much of the political structure in Philadelphia was for [then-state Treasurer] Bob Casey. And Mike Nutter worked for me when I ran for governor in 1986. And Dwight Evans has done so much for me in Harrisburg. They're all fine guys and I have strong emotional ties to every one of them."