In most Philadelphia mayoral elections, the returns can be read in black and white. This year, more voters are coloring outside the lines.

The race for the Democratic nomination remains a toss-up with just 16 days left - in part, polls say, because white millionaire Tom Knox is drawing a healthy share of black support and former City Councilman Michael Nutter, who is African American, is drawing a healthy share of whites.

History suggests that is rare. In the last quarter-century, few other major U.S. cities have been so prone to voting on racial lines.

Maybe that is changing.

"What we see here is an unusual case. Race is generally the most reliable predictor of voting behavior," said Ron Lester, a Washington-based pollster and expert in urban campaigns who is watching Philadelphia closely this year.

"The question is: Is it a fluke, because voters are in a very foul mood?" Lester said. "Or is this pattern something that will be ongoing?"

It's too early to know the answer. Negative campaign ads have begun blossoming only in recent days. And pollsters are wary of voters who profess color-blindness before Election Day.

Still, experts have been impressed by the campaign's nonracial, noninflammatory tone thus far.

"This is maybe the most policy-wonkish debate I've seen in a Philadelphia election in decades. You may have to go back to Clark and Dilworth in the '50s," said G. Terry Madonna, director of the Keystone Poll at Franklin and Marshall College, referring to mayors of a half-century ago. "This election is one in which whites and blacks perceive the city to have the same problems . . . so you don't have any racially divisive issues."

Strategists for the five mayoral rivals know the key to victory may lie in African American neighborhoods. Blacks make up just more than half the city's Democratic electorate in a typical primary, and a whopping 32 percent of black voters said they were undecided in a Susquehanna Polling & Research poll last week.

The rest of this pivotal group was split in the poll: U.S. Rep. Chaka Fattah, who is black, polled 23 percent of black voters; Knox 15 percent; State Rep. Dwight Evans, who is black, 10 percent; Nutter 8 percent; and U.S. Rep. Bob Brady, the white Democratic city boss, 4 percent.

(Overall, the poll of 450 Democrats had Knox at 20 percent, Nutter at 18, Fattah at 14, Brady at 9, Evans at 7 - and 27 percent undecided. The margin of error was plus or minus 4.6 percentage points.)

Knox's rags-to-riches rise from public housing, highlighted again and again in his TV ads, has struck a chord with many black voters, according to polls and interviews. Lester's polling, done for the Philadelphia Tribune, found Knox scoring as high as 17 percent of African American voters.

Knox "is somebody who understands our plight but doesn't necessarily look like us," said antiviolence activist Mark Harrell of Men United for a Better Philadelphia, who said he was undecided. "As I look at the candidates, this is probably the most split the black community has been in recent elections."

The pattern in Philadelphia the last 25 years has been for black voters to unite around the most viable black candidate.

Consider 1999, when it looked as if Martin Weinberg, a onetime adviser to Mayor Frank L. Rizzo, might win the Democratic primary. Black voters moved in the last few weeks from other African American candidates to coalesce around John Street, handing Street - who had stepped down as City Council president to run - a narrow victory. A similar dynamic elected the city's first black mayor, W. Wilson Goode, in 1983, and reelected him four years later.

Such racial consolidation could occur as the primary approaches. But so far, it has not happened, pollsters and strategists say.

"To have this high an undecided so late in the game tells me many black Democrats are not engaged," said James Lee, president of the Susquehanna firm, which conducted the poll for a business group. "It's not a polarizing election. I don't think most blacks see the white candidates as any kind of threat."

In addition, polls have shown a remarkably strong consensus across all demographic groups about the most important issue facing the next mayor - crime - and an almost equally strong cross-racial sense that the city is on the wrong track.

That environment has favored Knox.

"He's sort of new to the game," said Joan Walker, a retired teacher from Wynnefield who is African American. "Some of the others have had a chance and haven't done much. He's a fresh face, and I think he would have fresh attitudes. . . . And I think he's dedicated, because he's obviously not doing it for the money."

Claudette James, 68, said she was not too excited about any of the candidates but found Knox intriguing.

"Fattah, I'm sure, would do something right. I don't care much for Brady. He talks too much," said James, who is African American, as she sat with her granddaughter on the porch of the Tioga Branch of the Philadelphia Senior Center. "I would vote for Knox because I lived in the projects, too. . . . He knows how people have had to struggle."

Dana Kalins, a white Fairmount shopkeeper, on the other hand, has not been moved by Knox's biography. "That's a lot of bullarkey," she said. "Everybody's got a sob story."

Kalins prefers Nutter: "He seems real."

In the Susquehanna poll, 29 percent of white voters said they favored Nutter - twice the number who said they preferred Brady.

Thus far, the public campaign for mayor has featured few overt - or even coded - racial references.

For instance, when the subject of where to put the Rocky statue came up at a students' forum, Fattah said it should go next to Joe Frazier's statue - and then pointedly noted the lack of a monument to the hometown black boxing champion.

Around St. Patrick's Day weekend, orange-and-green "Tom Knox: Irish Catholic" signs sprouted along the median of Roosevelt Boulevard. And it's not as if old-fashioned white racism has vanished: Inside a pub Brady visited in the Northeast that weekend, the N-word could be heard outside the candidate's earshot.

Throughout the campaign, Fattah has pitched himself as the candidate who, in the words of his first TV commercial, will "lift our communities." The ad features an R&B backbeat and few white faces in it. Fattah talks of an "opportunity agenda": privatizing the airport and using the money to eradicate poverty.

His campaign also has an extensive grassroots-turnout organization, and canvassers have been talking face to face with voters for weeks, under the media radar, identifying potential Fattah supporters. And one of his strategists, Tom Lindenfeld, said it was too soon to imagine a big shift away from old voting patterns.

"There has never been an election here where the vote hasn't consolidated around race, so it's really hard to believe that we're in some new time," Lindenfeld said. "Voters are going to make a decision pragmatically based on who best can win, and Fattah is in better shape than anybody in the black community."

Despite some slippage, Fattah is running first among African Americans in most polls, usually followed by Knox.

Evans, a longtime legislator, has strong support from the Laborers and other mostly black unions, not to mention his base in the West Oak Lane neighborhood, which he is widely credited with saving. He is to appear tonight at a West Philadelphia rally sponsored by the citywide black ministers' group that has endorsed him.

Nutter, identified with ethics reform issues and the city's smoking ban, has consistently polled better among white voters than in his own racial group. He has moved to address this rhetorically - for instance, calling himself "an outraged black man" in reference to the city's epidemic of killings, which he also calls "black genocide."

He has had to contend with the perception that he is not black enough - a "watermelon man," sneered T. Milton Street Sr., Mayor Street's brother. In a meeting with Inquirer editors and reporters last week, Nutter said that perception frustrated him.

"I could've come in today with my jeans on halfway down my behind and my hat on backwards - if that makes you 'down,' " Nutter said. "I think that's nonsense. What the city needs is someone who's comfortable with themselves."

Shirley Pierce, a teacher who was grabbing a smoke outside the Brightside Day Care Center near 40th Street and Lancaster Avenue in Mantua, said she sensed that about Nutter.

"He's a 'people' person who gets out and mingles with people both in the ghetto and the upper state," she said, referring to wealthier neighborhoods.

An African American woman, Pierce said she believed race was overrated in the campaign. She all but personifies the voter that pollsters claim to have detected this year: less interested in race or rhetoric, more in the city's future.

Voters, Pierce said, "want somebody who can be fair to all. Not only are African Americans slipping back, so are the whites and the Puerto Ricans. We all want better schools, lower taxes, safer streets."

For profiles of the candidates and continuing coverage of the mayor's race, go to http://go.philly.com/mayorEndText

Contact staff writer Thomas Fitzgerald
at 215-854-2718 or tfitzgerald@phillynews.com.