The sharp surge in black turnout that Senator Barack Obama has helped to generate in recent primaries and Congressional races could signal a threat this fall to the longtime Republican dominance of the South, according to politicians and voting experts.
With the strong support of black voters, a conservative white Democrat, Travis W. Childers, scored an upset victory in that race, in a district held by Republicans since 1995. Kelvin Buck, a black state representative who helped the Childers campaign, said he saw a “level of enthusiasm and energy” that he had not seen before from black voters — significantly motivated, he said, by a recent Republican anti-Obama campaign.
The numbers appear to bear that out. In one black precinct in the town of Amory, Miss., the number of voters nearly doubled, to 413, from the Congressional election in 2006, and this for a special election with nothing else on the ballot. Meanwhile, in a nearby white precinct, the number of voters dropped by nearly half.
Still, it would take a shift in the electoral dynamic — a substantial stumble by John McCain, for instance — for Mr. Obama to put in play a state like Mississippi, where whites gave John Kerry only about 15 percent of their vote in 2004 and where voting in presidential elections is perhaps more racially polarized than anywhere else in the nation. Even with a heavy black turnout, Mr. Bositis estimated, Mr. Obama would have to increase his white percentage by at least a third, to about 20 percent, to win the state.
“I don’t anticipate him winning Mississippi,” Mr. Bositis said, even though it has a higher percentage of blacks than any other state, 36 percent.
Many of the votes on Tuesday for Mr. Childers — an anti-abortion, pro-gun-rights Democrat — were from whites who will in all likelihood pull the lever for Mr. McCain in November, analysts and voters themselves say.
“Obama, he’s too off-the-wall,” said Chappell Sides, a white Republican-leaning voter in Yalobusha County who said he was preparing to punch the button for Mr. Childers on Tuesday. “Hillary — I thought I hated her, till Obama came along.”