Ask political hands in the city why no significant challenger has emerged in this mayoral race, and they will tell you that in the absence of a strong African-American contender, Mr. de Blasio’s victory is inevitable. Some Democrats who would like to see a changing of the order have hoped Hakeem Jeffries, who represents the Eighth Congressional District in Brooklyn and Queens, would enter the contest. A former corporate lawyer with degrees from Georgetown and New York University, who grew up in Crown Heights, he is regarded as a singular individual who could successfully build a coalition between the affluent white business class, on whose money any bid would quite likely be dependent, and minorities. Those close to the congressman have long said he has no interest in running, and at any rate he is now becoming a leader of the Democratic Party nationally.

But the fact that his name keeps surfacing in these conversations is indicative of a much broader problem: the failure of the political culture to produce and groom a wider network of black talent, male or female. David N. Dinkins will be celebrating his 90th birthday in a few weeks; there has not been a black mayor in New York City before or since he held the office in the 1990s. For the past six years, black mayors have presided over Denver and Kansas City, Mo. Since 1974, there has been only one white mayor in Atlanta, which, like other Southern cities, has continued to nourish generations of leaders who came of age in the wake of the power base established by the civil rights movement.