Bill de Blasio (Kathy Willens/AP) Bill de Blasio (Kathy Willens/Associated Press)

After a piece last month about a second poll showing Bill de Blasio was not a one-poll wonder, a New York political operative close to the New York City public advocate e-mailed me with a prediction. De Blasio has “staying power.” When I asked whether it was possible for his candidate to snatch the black vote from the only African American in the race, the answer was succinct. “Yup. I do. Particularly amongst black women,” he replied. He was right on both counts.

Michael Barbaro of the New York Times delivers a fascinating tick-tock on how de Blasio went from the back of the pack to the top of the heap in the race for the Democratic nomination for mayor of the Big Apple. And a dive into the exit polls shows how thoroughly de Blasio’s disciplined strategy worked.

De Blasio won just about every demographic. You name it, he won it. For instance, City Council Speaker Christine Quinn was the only openly gay candidate and the only woman in the race. She lost the gay vote to De Blasio, 47 percent to 34 percent. She also lost the women’s vote to him, 39 percent to 16 percent.

But let’s focus on African Americans. Former city comptroller Bill Thompson was the only African American in the race. He and de Blasio tied for the black vote with 42 percent each. Now, let’s take a deeper dive. Thompson beat de Blasio among black men, 49 percent to 36 percent. As predicted, De Blasio won black women, 47 percent to 37 percent. But here’s the kicker: While black men were 12 percent of voters, black women made up 17 percent.

“Thompson lacks vision or energy,” my Big Apple source said. “He doesn’t connect.” Count that as a shame because Thompson is a smart, capable guy. Unfortunately, he has as much fire as a match under running water, and he completely blew the opportunity handed to him four years ago. Thompson came within four points of denying Mayor Bloomberg a third term. That near-victory gave Thompson a natural platform to build a constituency as the city’s alternative voice. He did nothing with it.

Chirlane and Bill de Blasio head to the polls. (Brendan McDermid/Reuters) Chirlane and Bill de Blasio head to the polls. (Brendan McDermid/Reuters)

But when it comes to Thompson and the black vote, I believe there was something else at work. As we all know, de Blasio’s wife Chirlane is African American. But my unscientific and generalized analysis after more than four decades of observation says that a white male public person with a black wife or girlfriend gets major approval from African Americans in general and black women in particular. It’s the most tangible sign that “they” all don’t hate us and that some of “them” not only understand us but also know us.

Take that feeling, add the affirming Afro-wearing Dante, mix in that wonderfully joyous picture of the biracial de Blasio family working it out during the West Indian Day parade and overlay it with de Blasio’s full-throated opposition to stop and frisk, and you’ll see why the black vote split between one of their own and, well, one of their own.

Follow Jonathan Capehart on Twitter.

Jonathan Capehart is a member of the Post editorial board and writes about politics and social issues for the PostPartisan blog.