Michael Nutter's victory as the Democratic Party nominee for mayor in Tuesday's election could mark a real turning point in Philadelphia politics.

I have been watching local elections for a few decades now, and this mayoral primary was unlike any I have ever observed. For one thing, Tuesday's results could signal an end to old machine politics in this town. Even more important, the numbers suggest that, from now on, a candidate's race may play less and less of a role in voters' decision-making.

Nutter made history by becoming the first African American candidate for mayor to get more than 20 percent of his party's white vote. He got 37 percent of that vote (the highest percentage for a black candidate since such things have been tracked) and 40 percent of the black vote.

You could conclude that Nutter's base consists of both white liberals and black professionals. If he is successful in the November general election, he will become the city's third black mayor, and the first black mayor to succeed another.

To return to my first point, the results Tuesday may mark the end to old machine politics. The fact that the Democratic Party boss, U.S. Rep. Bob Brady, came in a distant third behind political outsider and millionaire businessman Tom Knox may be that marker.

Both Nutter and Knox argued for change in the political status quo. Pay-to-play corruption and the need to change the system were dominant issues in the campaign.

Although the majority of Knox's support came from white voters, a quarter of his count did come from black voters, even though there were three black candidates in the race. Knox, who has never held elective office and worked for former Mayor Ed Rendell for a year, was an early leader in the polls.

What made the difference? Knox did not come across as someone who was really comfortable as a candidate, and he made less of a case (compared with Nutter) that he could manage the complexities of a large municipal government. Knox's outsider status helped him as a general candidate, but he may have seemed too much of an outsider to challenge Nutter.

Nutter's record in City Council and his campaign message were those of a rebel insider. His extemporaneous remarks were more facile and smooth than Knox's; Nutter's poise and focus during the debates made him a standout.

Another dominant issue is crime, and the fear that comes along with a high homicide rate in impoverished black neighborhoods in the city.

The traditional mayoral campaign issues, such as public education and the lack of municipal services, were much less in evidence than usual at many public forums and debates held all over the city.

Although it was an unusually strong field, with five viable candidates, it is clear to me that Nutter ran the most effective and substantive campaign. In the debates, he came across as smart, hardworking and sincere. His television ads were better focused than his opponents', especially the one in which his 12-year-old daughter, Olivia, appeared. In the ad, she asserts that "my dad is the only mayoral candidate whose daughter goes to public school," a reality that resonated with many people.

The results are extraordinary when you factor in that the election was a contest among three black candidates and two white ones.

U.S. Rep. Chaka Fattah, who entered the race in first place, was considered the front-runner. But he and State Rep. Dwight Evans, a popular and experienced politician, both ran disappointing campaigns. Evans finished last and Fattah finished third, more or less even with Brady.

There was considerable banter among voters that Fattah and Evans should stay in the positions they currently hold.

All of the candidates, overall, ran campaigns that spoke well of this city. When I think back to campaigns when Frank Rizzo was a candidate - especially the occasion in 1978, when he urged voters at a ward meeting to "vote white" - I can hope the city really is changing.

Thinking back to 1983, when the city's first black mayor, W. Wilson Goode, won the Democratic primary - I say what a difference a decade or two can make.

Goode won the Democratic nomination in 1983 with the almost complete backing of black voters. Black registration was 98 percent, and the turnout was 90 percent. He also received financial backing from thousands of contributors from the community in what was clearly a bottom-up movement.

A few in the African American community are questioning Nutter's commitment to solving problems. It is too early for that skepticism. I congratulate him and praise him for running a great campaign and proving all doubters wrong.

For sure, Nutter's leadership will be tested in the November general election. Once he wins, he becomes mayor of all Philadelphia. He can no longer be a rebel insider.

Contact Acel Moore at 215-854-4533 or amoore@phillynews.com.