ATLANTA - The county elections board yesterday certified the results giving former State Sen. Kasim Reed a narrow victory in the city's mayoral runoff vote. With the win, the black political machine that integrated Atlanta's City Hall - and kept it that way for four decades - pulled through one more time to deliver a fifth consecutive black mayor.

Barely.

With 84,383 votes cast on Tuesday, Reed beat city councilwoman Mary Norwood by 715 votes, a margin of less than 1 percent. Norwood's campaign manager, Roman Levitt, said the campaign plans to request a recount tomorrow.

The fissures in the political machine have been exposed, its future viability in doubt.

Atlanta's black population has shrunk and its white population grown since its current mayor, Shirley Franklin, was elected in 2001. Its voting rolls are filled with newcomers unfamiliar with Atlanta's habit of assigning its business interests to whites and its political interests to blacks.

The reality is sinking in that black political power in the city is not as strong or united as it once was, and is destined to weaken as more whites seek office and more African Americans shed their civil rights-era consciousness.

"The racial issue has always been there," said former State Rep. Bob Holmes, who has studied Atlanta politics for more than a decade. "It was higher and closer to the surface in large part because this was the first election in 20 years where there was a significant white candidate. But there appeared to really be unity in the black community."

Atlanta's allure as the black mecca focused national attention on the race, as African Americans across the country watched to see whether the city would remain a beacon of black leadership. Reed raised a million dollars during the runoff campaign - one-quarter of it from out of state.

Both black and white voters showed a willingness to stick to their own. Of the city's 537,958 residents, about 237,000 are registered voters. According to the latest data from the U.S. Census Bureau, Atlanta's population is 56 percent black and 38 percent white.

The city's population has swelled by more than 76,000 since 2000, when the black population was 61 percent and whites made up 33 percent of the city's residents.

More than 84,000 ballots were cast in the runoff, about 5,700 more than in the general election, and the outcome itself hung on the votes from Atlanta's most staunchly segregated enclaves.

A major challenge to the machine is the thought, rapidly taking hold, that black leadership has not always meant black progress - the city has a poverty rate of 22 percent, far above the national average of 13 percent.