John F. Street likewise faced no Democratic primary opponent when he campaigned for a second term as mayor in 2003. But there he was, running television ads two weeks before the May primary - and he didn't face Republican Sam Katz in a high-profile rematch until six months later.
Despite their lack of primary opposition, both Street and Rendell each managed to draw about 175,000 voters to the polls; that amounted to about one in three registered Democrats for Rendell, and one in five for Street.
Given the lackluster mayoral race this year, it is questionable whether that many Philadelphians - or few, as the case may be - will come out to vote May 17.
"This may not necessarily be the most exciting race in the world, but elections happen only twice a year, and voting is a part of citizenship," Nutter, in jeans and a red City Year sweatshirt, said Saturday, urging residents to vote as he shook hands, posed for pictures, and walked north on Broad Street during the Philadelphia International Festival of the Arts.
As with most incumbents, how many votes Nutter gets - or doesn't get - will be viewed as a referendum on the mayor himself.
At the same time, the number of ballots cast for Street, the city's former First Brother, an ex-convict and an ex-state senator, will also be closely assessed by, among others, two municipal unions yet to negotiate new contracts with the Nutter administration; city and state elected officials who will work with the mayor in the next four years; and, to be sure, anyone contemplating a last-minute write-in campaign against Nutter in November.
Nutter, for his part, maintains that he is in regular touch with residents as the city's full-time mayor, if not a full-time candidate. "What I was elected to do is run the city, and I spend 16 to 18 hours a day doing that, and somewhere in between, I am also campaigning," he said. He maintains an active Facebook page, and has over 8,200 followers on Twitter, where he tweets nearly every day.
"People are still in crisis," the mayor said. "They have a lot of anxiety about jobs and about the future. I experience that each and every day as I'm out talking to real Philadelphians."
One of those "real Philadelphians" is Alice Steinitz, an eighth-grade teacher at Sharswood School in South Philadelphia. As the mayor walked toward her at Saturday's arts festival, she turned to her 4-year-old son, Noah, and told him: "Say your mommy is a teacher and he needs to support us."
Nutter's campaign is being organized in part by the Black Clergy of Philadelphia, which is scheduling church visits for him. The mayor has also held routine news conferences publicizing unions and political groups endorsing him.
On Wednesday night, he is scheduled to hold a final fund-raiser before the primary election at the Hotel Palomar in Rittenhouse Square.
And on Friday the 13th, his senior campaign adviser, 72-year-old "shrimp king" Sid Booker, will hold a rally for the mayor outside his well-known North Philadelphia restaurant, the Stinger Lounge.
Acknowledging that the election has not sparked much interest among his mostly African American customers - "they are not talking about it like they should be talking about it" - Booker has taken it upon himself to persuade people in one-on-one conversations to vote for Nutter.
"When I get done talking to them, they seem to be OK," he said. "They say, 'OK, Sid. I know you won't tell me nothing wrong.' "
Radio ads, now running on KYW, Power 99 and WDAS, feature city residents lauding Nutter as making City Hall more transparent, reducing crime, creating jobs, and advocating for after-school programs and summer jobs.
But he is not giving rousing campaign speeches or going door-to-door for votes. His campaign does not distribute a daily schedule. And last week, with the primary three weeks away, he spent three days in Chicago at a national mayors' conference on urban design.
At his campaign office one day last week, the phones were quiet. On hand were six or so full-time staffers, and a few boxes of red campaign T-shirts and buttons ready to be distributed.
Some political consultants interviewed said the lack of general interest in the race may benefit the mayor since the people who vote rain or shine are not viewed as Milton Street supporters.
Indeed, if anybody to date has brought attention to the fact that a campaign is going on, it has been Milton Street.
"I hope the mayor keeps doing what he's doing, whatever that is," Street said last week. "I think he is going to be in for a rude awakening on the 17th."
Street counts family members - excluding his younger brother, the former mayor - as part of his official campaign staff, and has a small campaign office at 12th and Vine Streets.
Street campaigns on the subway, at bus stops, and at busy commercial corridors. Last weekend, a motorcade with a recorded Street message drove through Germantown, Mount Airy, and elsewhere.
He regularly e-mails reporters with comments about Nutter - such as the mayor's decision to have his chief integrity officer investigate a school management contract at Martin Luther King High School instead of a stronger, more independent office such as the district attorney or inspector general.
"Even though Milton has raised some viable issues, I don't think people take Milton as a serious candidate," community activist Bilal Qayyum said.
He added: "I do wish the campaign were more lively, though, because the more dialogue, the more issues discussed, and the more engagement, the better for the city."
Contact staff writer Marcia Gelbart at 215-854-2338 or firstname.lastname@example.org.