The Rev. K.B. Martin - the pastor of Antioch Baptist Church and one of the city's most prominent clergymen - doesn't know if he would classify his recent decision to support Mr. Walker's opponent as a coup. He does, however, concede that promoting a white Republican from the pulpit of a black church has caught many people - white and black - off-guard.

Can Mr. Walker be beaten?

Political experts say probably not, but support from black leaders such as the Rev. Martin is one of the few things that could turn the tide and end Mr. Walker's five-term winning streak to Randy Hall, a local lawyer running on the Republican ticket.

"It is very unusual for a Democrat to support a Republican," the Rev. Martin said Friday afternoon by telephone.

"I just think Randy is the better candidate for the job," he said. "And he has the total community at heart."

But there are rumblings that the Rev. Martin's endorsement, along with support from several other prominent black clergymen, is another sign that a movement might be under way in the black community to unseat Mr. Walker, even if that means backing the most unlikely of candidates.

PERHAPS THE FIRST outward sign of unrest came earlier this week, when Mr. Walker's son, Charles "Champ" Walker Jr., did not garner the support of a majority of Augusta voters in his runoff campaign for U.S. Congress. He did win the Democratic runoff for the 12th Congressional District race, but his success was largely a result of the support of Chatham County voters.

The younger Mr. Walker lost the race in Richmond County, receiving 523 fewer votes - or 8 percent less - in local precincts than his challenger, state House Rep. Ben Allen.

That somewhat unexpected showing has prompted speculation of faltering support for the Walker name.

Now, the same black clergy members who got behind Mr. Allen are getting behind the senior Mr. Walker's competition for state Senate: Republican newcomer Mr. Hall.

"I think Sen. Walker is beatable," the Rev. Martin said, adding that his support, coupled with the support of several other black ministers, including the Rev. Clarence Moore of Good Shepherd Baptist Church, could sway thousands of votes Mr. Hall's way.

"I wouldn't write Randy off too soon," the Rev. Martin said. "Now that we have come out, a lot of people who have not come out on our side publicly will privately."

POLITICAL OBSERVERS are quick to point out that few, if any, assumptions should be made based on the results of Tuesday's primary runoff. Turnout was low; the race pitted two black Democrats against one another; and the younger Mr. Walker - unlike his father - is a political neophyte.

"The problem for the Republican camp is, where Champ Walker lost in a Democratic runoff primary, the choice was between two African-American Democrats," said Charles Bullock, a professor in the University of Georgia's School of Public and International Affairs. "So the question is, will voters who won't vote for Champ Walker in the primary, does that mean they would prefer a white Republican to his father? Past experience says the answer would be no."

Champ Walker's loss in the Augusta area was nonetheless surprising, he said, as is the support that black leaders are now giving to the senior Mr. Walker's competition.

It's not news to Mr. Allen, however, who - after his loss - plans to serve out his term in the House and then pursue a career in writing and teaching.

"There's a break in the base that Sen. Walker, for years, has enjoyed," Mr. Allen said. "The question is, is the break sufficient enough to weaken his hold on his Senate seat? And I think it's too early to say that."

He said he does believe Mr. Walker might be losing some support within the black community because of continuing allegations of ethics violations.

"I don't know whether it's fair or unfair, but the negative publicity he has gotten over the years, maybe some of that is beginning to stick and people are beginning to look more closely at the man," Mr. Allen said.

Media reports, paired with some growing sentiment in the black community that Mr. Walker has forgotten his core constituency, may hurt him at the polls come November, Mr. Allen said.

"Any good politician will tell you that all politics is local, and ... sometimes as persons in politics, you forget that politics is local until you overlook those voters at home who have always been a part of your support base," he said.

DESPITE WHAT SOME Democrats are quietly calling a groundswell of support to unseat Mr. Walker, he still is the favored candidate to win this year's Senate race. The district's population still has slightly more blacks of voting age compared to whites of voting age, and Mr. Walker has accrued nearly six times more in campaign contributions than his challenger.

Sen. Walker was in Washington and was not available for comment.

Mr. Hall is rapidly gaining financial support for his campaign, however. That, coupled with growing support from the black community, could pose a bigger threat to Mr. Walker than he's seen in several elections.

"We're not talking about black or white, or Republican or Democrat," Mr. Hall said earlier this week from his campaign headquarters on Broad Street. "We're talking about right and wrong. We have an elected official who has been a frequent visitor to the front page of the newspaper because of ethics problems, and that crosses racial and party lines."

As of Friday afternoon, Mr. Hall's campaign had reported more than $135,000 in contributions, about $100,000 of which was collected during the last quarter.

Also, when Senate districts were redrawn earlier this year, Mr. Walker's district had its black voting population reduced by nearly 12 percentage points, from 63.1 percent to 51.5 percent, making the district an almost 50-50 racial split.

The winner of the District 22 Senate seat still will have to secure a significant percentage of the black Democratic vote. Political experts say black Democrats almost never vote for white Republicans.

Clergy endorsements are one of the few things that could change that trend.

"If the Republican is endorsed from the pulpit, and if the sample ballots include him, that might enable the Republican to take a bite out of the black vote," Dr. Bullock said. "It would really take a real effort."

Local Democrats say they plan to fight that effort tooth and nail.

"I don't think we consider this a safe haven," said Lowell Greenbaum, the chairman of the Richmond County Democratic party. "We learned that in any election, people have to work hard to win. I think Sen. Walker certainly realizes that.

"We don't take anything for granted."

Reach Heidi Coryell Williams at (706) 823-3215 or heidi.williams@augustachronicle.com.