Last week’s election did not offer much good news for Republicans. But the brightest spot came from urban mayors who seem to have broken through the racial polarization that has too often held back the Republican Party.

In New York City, Mayor Bloomberg almost doubled his percentage of African American support to 46% from four years before, according to the Pace Poll. In St. Petersburg, Fla., an even more impressive milestone was reached, as Mayor Rick Baker won reelection in what local papers called not just a landslide but an “avalanche,” carrying more than 90% of the vote in heavily African American districts that he made it his mission to revive in pursuit of a “seamless city.”

Nine years ago, St. Petersburg was a city torn by riots with racial overtones. Few could have imagined that a conservative Republican who is the local campaign manager for Governor Jeb Bush would be the man who could resolve these tensions, but Mayor Baker has done just that.

On a trip down to St. Petersburg the week before the election, I visited areas that had previously been dogged by drugs and crime where the mayor was greeted warmly. Walking through a bustling area of downtown, a teenager with gold capped teeth bounded up to the mayor, practically hugged him and said, “Thank you for making our city a better place to live.” I wouldn’t have believed such Hallmark card outpouring of sentiment had I not seen it for myself. It is the product of what Rick Baker sees as common sense.

“My objective is for us to have a seamless city,” he says, defining the state as being “when you can drive from one part of town to the other and not feel the need to reach over and lock the car door.”

Mr. Baker sought to bring this about by focusing on reviving the long-neglected area now christened Midtown. Traditionally the heart of the St. Petersburg African-American community, it was hardly considered home turf for Republicans in this largely Democratic city. When skeptical citizens asked Mayor Baker why he was devoting so much time to the area, he had a simple response: “First, it is the morally right thing to do. Second, it is also best for the rest of the city. We allocate each year a disproportionate amount of our resources to these troubled communities and don’t get any taxes back. If we turn it around, we will.”

He began by studying the Manhattan Institute classic “The Entrepreneurial City” and ordering all appointees to read the book as well. He put the Broken Windows theory to work by literally cleaning the streets and prosecuting those who were illegally dumping construction garbage on the neighborhood’s vacant lots. He also cracked down on the street criminals who made the area notoriously unsafe – drug arrests are up more than 30%.”I am trying to make it as unpleasant for drug dealers as I know how,” Mr. Baker says. “We are going after the bad, but we are also working to improve the good.”

Well-intentioned efforts at urban renewal have a long history of failing since the counterproductive cash-flow of the Great Society, but Mr. Baker has taken a different approach, focusing instead on market solutions and public-private partnerships. An industrial park was established in Midtown, and City Hall worked with the community to attract businesses to the area. Like Harlem a decade ago, Midtown residents were deprived of basic services: no supermarket; no bank; and a post office that functioned like Fort Apache in the Bronx. Now, a new premium supermarket has opened up, a new bank is on the way, and residents can actually mail letters and buy stamps at the post office. There has also been an emphasis on restoration – the once abandoned Royal Theater has been transformed into a state-of-the-art local arts center, and the segregation-era Mercy Hospital, which had become a haunt for drug dealers and prostitution, is now a thriving neighborhood health clinic. These identifiable improvements are what translated to 90% support – highlighting the often-denied fundamental fairness of the African-American vote.

This has helped fuel the broader boom in St. Petersburg, where there is currently more than $1 billion of construction going on downtown, including the movement of the Salvador Dali Museum to a new building and an open air venue for the local symphony, along with condominiums, a children’s hospital, two new hotels. Just as Mayor Bloomberg adopted the traditionally Democratic issue of public education as a cornerstone of his administration, Mayor Baker teamed up with local businesses to establish company sponsorship for individual public schools, helping test scores to rise at four times the state average. And it is telling that Mayor Baker’s opponent, labor attorney Ed Helm, tried to make party loyalty the core of his campaign. Like Fernando Ferrer, he failed.

The lessons seem clear: First, the third-way model of mayors is alive and well – urban voters are increasingly turning away from party labels and toward leadership that gets results. Second, Republicans can break through paralyzing racial polarization by reaching out to minority communities in the spirit of mutual respect and clear commitment to improving their quality of life. Finally, public-private partnerships remain the best way to bring about urban renewal, creating a shareholder’s society where everyone feels an interest in the success of the whole.

As Republicans look beyond this past election, they would be wise to study such urban examples of the politics of addition to guide them into the future with a broader base.