New York mayoral hopefuls going to great lengths...and distances...to win City Hall

The road to City Hall runs through ... Cincinnati.

New York's four Democratic mayoral candidates flew to the Ohio city at the request of the teacher's union president, Michael Mulgrew. They want his endorsement - and he wanted them to see an innovative program in Cincinnati's schools.

The road to City Hall also runs through ... the Regency Hotel.

That's one of the places where the candidates have been breaking bread with the Rev. Al Sharpton, part of an elaborate courtship of the civil rights leader.

The 2013 election is 10 months away, but a secret, shadow primary has long been in high gear.

With power breakfasts and phone calls, position papers and even trips to Ohio, the candidates have been going to extraordinary lengths to line up the backing of political and civic power brokers.

“It’s a delicate balance between (<NO1><NO>being<NO1><NO>)friendly and gaining someone’s trust and being obsequious and <NO1><NO>a<NO1><NO> stalker," said political consultant Evan Thies.

"You want to be sort of (more)Don Juan wooing the target than Eddie Haskell (saying) ‘You look great today, Mrs. Cleaver!’ And it'’s tough. Some people can’t do it. (But)a lot of the success of the campaign happens before people even declare they're running for office."”

When Mulgrew, boss of the United Federation of Teachers, suggested the candidates accompany him to inspect a Cincinnati program bringing social services into public schools, they all complied.

Two of them - city Controller John Liu and Council Speaker Christine Quinn - had the city pick up the tab, maintaining that what they learned was relevant to their work as city officials.

The other Democrats, Public Advocate Bill de Blasio and former Controller Bill Thompson paid for the trip with campaign funds.

The journey was a chance to spend more time talking about the future of education with Mulgrew, who said he was also impressed that the candidates reached out to him after Superstorm Sandy and stood with him in cleaning up the wreckage.

"Where I come from, standing side by side in the mud, going out on a trip with no media coverage, finding things that are really going to work (for schools is what's) going to make a difference in my mind," said Mulgrew, a Staten Islander whose home suffered flood damage.

Mulgrew does have his limits. He said Republican candidate Tom Allon offered to underwrite a jaunt to Finland to scrutinize its education system after Mulgrew talked about it in a speech - but the union boss said he thought that was a bit much and declined.

When it comes to wooing Sharpton, the courtship is a family affair.

"They're not only wining and dining me, they’re wining and dining members of my staff," Sharpton adds. That would include his daughter, Dominique, 26, the membership director of her father's National Action Network.

She's known all the candidates since she was a little girl. While she's particularly close to "Uncle Billy" Thompson, who'll chat with her about her goals over dinner at uptown mainstays like Sylvia's and Red Rooster -- and the "perfect gentleman" always picks up the check, she says -- she's worked closely with Quinn on ways to combat crime, had de Blasio over to her house for dinner and can spend hours on the phone with Liu, chatting about his family.

"It’s cool being the daughter of Reverend Sharpton -- you're the next one to speak with or garner support from," she said while emphasizing that the decision-making falls to her dad. "I just do what I can to push the issues."

Her father says he's met with each of the Democrats at least four times each - a figure that goes up to 20 if their visits to his weekly radio broadcasts and his demonstrations against street violence are included.

Sharpton says he's been treated to breakfast at The Regency and frequently gets calls on his cell phone from hopefuls just "checking in." If it's not them, he says, it's their surrogates.

All fine, but "I know the difference between laying out real policy and trying to do a rub your back and smile thing." which is why in January, he told the News, instead of his usual Martin Luther King Day observance, he plans to personally grill the candidates in a forum that will be taped and excerpted for his MSNBC show, "Politics Nation."

Some tastemakers long ago pledged their allegiance and consider themselves impervious to any come-ons, including former Mayor David Dinkins and ex-Bronx Borough President Fernando Ferrer, who twice ran for mayor himself.

Both are solidly in Thompson's corner, though they say they like all the candidates and, as Dinkins puts it, "There is always the wise politician (who can) always sort of suggest that 'If your guy finishes out of the money, think about me.' Right now, I refuse to entertain the idea that (Thompson) won't win."

As for Ferrer, "I continue to talk with all of them, or nearly all of them... but I've been very clear about Bill from the last election, and I don't believe in pussyfooting around and playing that game," he said. "I think they would insult themselves by asking me to change my mind."

Union kingpins like Stuart Appelbaum, president of the Retail, Wholesale and Department Store Union, says he's chatted up by many candidates who want the 2013 green-light, but he makes sure to keep the boundaries clear when the waiter brings the check:

"I don't want anybody to say I’m supporting them because they bought me a chef salad," he joked.

The end of the shadow primary cannot come soon enough for Wanda Williams, political director of the largest municipal union, District Council 37. She says she has been bombarded for months with calls from the "anxious" mayoral wannabes, even on weekends.

"There are four candidates that are really, really bugging me to get DC37’s endorsement (on)a weekly basis," Williams said. "They keep calling. They're very desperate."

ckatz@nydailynews.com