Four years after overwhelming support from black voters nearly carried Bill Thompson to an improbable upset of Mayor Michael Bloomberg, the lone African-American candidate for mayor is facing a stiff challenge for their support this time around.

The race’s new front-runner, Bill de Blasio, has resonated with black voters as a harsh critic of stop and frisk and the father of interracial children. And with the Sept. 10 primary fast approaching, de Blasio’s support among blacks appears to be growing.

“It is a mistake to say the African-American vote is monolithic,” said political consultant Basil Smikle. “The African-American community is changing — there is a diversity in income, in education, in where we live. … There’s not a knee-jerk reaction to get behind the black candidate.”

Black voters are expected to make up about 30 percent of the primary electorate, a bloc that could have a key role in determining who gets the Democratic nomination.

De Blasio, who is white, was the choice of 34 percent of African-American likely Democratic voters polled by Quinnipiac College last week, a 4 percentage point jump in two weeks. Thompson tallied 25 percent, while City Council Speaker Christine Quinn, who is white, landed 15 percent.

Overall, de Blasio was the choice of 36 percent of voters in the latest poll, putting him tantalizingly close to the 40 percent he needs to avoid a runoff. If no candidate crosses that threshold, the top two finishers square off Oct. 1. Thompson and Quinn are fighting a pitched battle for second.

De Blasio is married to an African-American woman, and their 15-year-old son, Dante, has been the star of two of his campaign’s TV ads. Dante’s afro has quickly developed a cult following on Twitter, where it generated a hashtag (#fromentum) and later backlash from critics who found the campaign’s spotlight on a child and his hair exploitative.

But de Blasio’s interracial family does not solely explain the public advocate’s surge, argued Smikle.

“I think a lot of African-American voters want a fighter,” said Smikle, who is unaffiliated with any campaign. “They want someone who has fire in his belly, someone who is not afraid to push the institution.”

Many black voters were first drawn to Anthony Weiner’s feistiness. For weeks, Weiner polled best among black voters, but many switched to de Blasio when the former congressman’s support collapsed amid another sexting scandal.

Throughout the campaign, de Blasio has positioned himself as the anti-Bloomberg and he benefited the greatest from the debate surrounding the police practice of stop and frisk even though his position is similar to those of his rivals, including Thompson.

De Blasio and other critics say the tactic, which the New York Police Department uses to stop people deemed suspicious, discriminates against blacks and Latinos, while its supporters say it drives down crime.

“I feel like he gets it,” said Derick Johnson, 53, a retired welder who lives in the Bedford-Stuyvesant neighborhood of Brooklyn. “There’s truth inside of him.”

Thompson — who landed the support of 78 percent of black voters when he ran against Bloomberg, according to exit polls — has relentlessly claimed that polls have undercounted his black support in the latest race and that those voters will break for him late and push him to the runoff.

Thompson’s team has launched an aggressive get-out-the-vote operation in 19 minority-heavy state legislative districts. He has picked up endorsements from heavyweights within the African-American community, including former Mayor David Dinkins, U.S. Rep. Charles Rangel and the Rev. Calvin Butts, the head of one of Harlem’s largest churches.

He is also deploying prominent African-American leaders from across the country, including Rep. James Clyburn of South Carolina and Rep. John Lewis of Georgia, to campaign in the city next weekend.

Dawn Ward, a retired bus driver, voted for Thompson in 2009 but was having a hard time deciding among him, de Blasio and Quinn in what she deemed a “flip-floppy race.”

“I always liked Bill Thompson. I think he’s a decent guy,” said Ward, who lives in Bedford-Stuyvesant. “I wish I could wrap all three of them together into one.”

(AP)