Now comes the hard part for Michael Nutter, Philadelphia's next mayor.

You can call his victory Tuesday convincing, but it's hardly a mandate.

Among a field of five major Democratic candidates, the former city councilman won with 37 percent of the vote, defeating his nearest rival, Tom Knox, by 12 percentage points.

But, consider this:

There are 1.4 million residents in Philadelphia and Nutter got a total of 104,000 votes.

There were only 11 wards - out of the city's 69 Democratic wards - where he polled more than 50 percent of the vote.

The city's 150,000 Republicans couldn't even vote in this round. They will have to wait until November, when Nutter's Republican rival will be Al Taubenberger.

More than half the city's 750,000 registered Democrats sat this primary out. Despite all the talk about this being a defining moment for the city, they never bothered to vote.

To sum up, Nutter was chosen by a fraction of a fraction of the electorate.

I'm not saying this to put a damper on the celebrations in the Nutter camp, but to point out the reality of the situation.

If Nutter seizes the moment, he can turn this reality into an opportunity.

You know and I know (and probably Taubenberger knows) that Nutter is, de facto, the mayor-elect of Philadelphia. That's the reality in a city where D's outnumber R's by nearly 5-1.

But that doesn't mean the Democratic nominee should take the summer off. He can use the months ahead to sell himself and his agenda to the majority of voters who weren't Nutter supporters: Republicans, no-show Democrats and D's who supported other candidates in the primary.

These next six months can be used to close the deal with all Philadelphians, so his victory Tuesday does become a mandate in November that carries him into his first term.

Lord knows, he'll need the support, given the challenges he faces: putting a dent in the crime numbers, negotiating a new contract with the city's labor unions, balancing a wobbly city budget, advancing the nebulous cause of "reform" that his election is said to portend.

But he enters this phase of the campaign with some assets:

He has proven a cross-racial appeal. In the primary, it appears Nutter got about 40 percent of the black vote and 35 percent of the white vote. In a majority-minority city, with a polyglot mix of races, ethnic groups, not to mention economic classes, he is the guy with the potential to appeal across racial and class lines. Continue to build these bridges and it will make governance easier.

He has shown he has the potential to be a good public leader. The book about Nutter has been that he is a smart guy, but he can be a loner who has a tendency not to listen. Do those traits remind you of anyone? How about John Street, currently mired at a 21 percent approval rating in the public polls. In the primary, Nutter dispelled some of those doubts by being open, engaging and hardly ever losing his cool. There's something to build on. People are yearning for a Not-Street leader. Nutter can prove he is that man.

He has emerged as the candidate for reform. It's more of an urge than a platform, but there it is. Taken together, Knox and Nutter - the two candidates of change - won 65 percent of the Democratic electorate on Tuesday. There's a message in that. Folks are tired of the usual way of doing business in the city, tired of pols playing to special interests. What they want is a city government that treats you and me and that fellow behind the tree the same. Nutter came closest to articulating ways large and small where that can be accomplished. He can reinforce that image with an agenda that lays it out.

Nutter is committed to a pro-growth agenda. He knows the only way for this city to prosper is to bring in more jobs. The only effective way to do that is to create a competitive business climate. And the only way to accomplish that is to lower the various taxes and fees that make Philadelphia the No. 1 or No. 2 (depending on the survey you use) most expensive place to do business in America. Given the demand and need for city services, given the city's 25 percent poverty rate, that may be Nutter's toughest sell.

So, here's my free advice to Tuesday's winner: Take a week off and relax, then get to work. You've got six months to sell yourself and your agenda to the rest of Philadelphia.

Contact Tom Ferrick at 215-854-2714 or tferrick@phillynews.com