Bill de Blasio, whose strong support in New York City’s Democratic primary for mayor may have averted any runoff, had a secret weapon — and I speak not of his delightful Afro’d son, Dante, but of the very man he wants to succeed, Mayor Michael Bloomberg.

Yes, if anyone handed de Blasio a win — besides de Blasio, his campaign and his feckless opponents — it was Bloomberg. He has never fully understood the art of politics, governing stubbornly with his head, never his heart. He has been substantive and steady, he has had many successes. But his inability or unwillingness to empathize with the public, especially on such gut matters as the policing policy of stop-and-frisk, gave de Blasio an opening. The public advocate campaigned as the anti-Bloomberg — and it worked.

The mayor can be persuasive, one on one. But it is a Bloomberg the public barely glimpsed. I recall thinking this a few months ago, when I was visiting a friend at Bloomberg News, and the mayor walked in. Within seconds he was lecturing me about the effectiveness of stop-and-frisk, urgently defending the policing policy, making his familiar arguments about deterrence, the importance of reducing gun possession through the police stops, which a federal judge has since said violates the constitutional rights of minorities.

The police stops and the mayor’s assertions remain in dispute. But most notable to me about that Bloomberg encounter is not what the mayor said, but how he said it. His tone was devoid of the scorn, anger and disdain he displays like a shiny badge whenever his judgment is questioned.

I recall thinking it was a shame the public rarely heard him the way I did that afternoon. He might not have changed many minds, but could at least have generated a less tendentious debate than we have been hearing in this mayoral election season about a difficult and sensitive subject. It might even have changed the outcome of the primary.

I am convinced that de Blasio led the Democratic field not only because of who he is — champion of a populist, liberal ideology — but also because of who Bloomberg is. The public advocate bested his opponents largely in reaction to a mayor who has never accepted the political value of connecting to the wider public.

That gave de Blasio a way in: He ran as the anti-Bloomberg. City Council Speaker Christine Quinn, the mayor’s longtime ally, ran as Bloomberg-light; Bill Thompson, always a centrist, woke up too late to the public’s unhappiness with Bloomberg and his policing policies; Anthony Weiner — is Anthony Weiner; John Liu, the city’s comptroller, never registered with voters.

But de Blasio sure did. Realizing that the Democratic primary voter is typically more liberal than the general electorate, the longtime activist decided not to modulate his liberal-left ideology. Instead he promoted it — reinforcing his identity as the antithesis of Bloomberg.

Even the temperaments of the two men could not be more different. Bloomberg is fiercely private. De Blasio has run as open and friendly, promoting himself as a family man and promoting his family — especially Dante, star of the campaign’s popular TV commercial.

The public loved the de Blasio approach; the mayor hated it. He hated, too, that de Blasio was running against him, maybe more than he ran against his Democratic rivals. Bloomberg displayed his annoyance by denouncing the de Blasio campaign as racist and divisive in a New York magazine interview that ran the week before the primary.

The mayor even played right into de Blasio’s “tale of two cities” theme during that interview, saying how great it would be if the city could get “all the Russian billionaires” to move to New York. As if everyone in town would welcome an influx of Russian oligarchs while they struggle to pay the rent and get their kids into a good public school.

The incumbent mayor has always dismissed the importance of connecting with the public. He’s been the data-driven mayor, the kind of leader who rarely used his bully pulpit. New York’s very own Mr. Spock has asserted, not persuaded, as if puzzled, even annoyed, by those who are not as impressed with logic and statistics as he is.

Bloomberg rarely saw the benefit of appealing to the public, of showboating his successes — even of just showing up. Early in his first term, Bloomberg resisted the advice of wiser aides, who tried to get him to be more of a personal presence around the city.

They told me about an incident early in the first term, when a water main broke in the Bronx — leaving 2,000 New Yorkers without water. Go to the scene, they urged. He would not. “I’ll be in the way,” he said, arguing that he could do nothing personally about a water main break. It would be more useful attending to business back at City Hall.

True. But he missed the point. Bloomberg, new to politics and 59 when he ran for City Hall in 2001, has never realized that governing is also feeling your pain — or pretending to feel your pain. He has gotten a great deal accomplished — thanks to his smarts, his independence and his wallet — and has improved his public act over the years. But he has never made himself into an approachable leader, and his intransigence has come at a price. The public ran out of patience with him.

Of course, New Yorkers have historically had little tolerance for lame-duck mayors. We are an impatient lot, reflecting the constantly changing city that is our home. Of all the Democratic candidates, only de Blasio recognized and played to the city’s innate restiveness, and so positioned himself where his progressive background made him most comfortable anyway — as Bloomberg’s polar opposite.

If he wins the runoff (if there is one), and defeats Republican Joe Lhota, he will have the current mayor to thank — maybe even more than Dante. There is no question, in this voter’s mind at least, that if Bloomberg had ever developed a personal rapport with those who are not developers or business executives, if he had taken the time to explain and persuade, the pendulum would not be swinging quite so widely as it now seems poised to do.

(Reuters)