In a district that’s almost evenly split along party lines, Rep. John Barrow (D-Ga.) always has to be worried about a serious Republican challenge in the general election.

But considering that Georgia’s 12th district is almost as evenly split between black and white voters, a serious black Democratic challenger, like the one who filed Monday to run against Barrow, could give the white sophomore Congressman just as much trouble.

The surprise candidacy of state Sen. Regina Thomas (D) creates the very real possibility of a tough Democratic primary fight for Barrow this July. And that has given Republicans renewed hope as they try to move the battleground eastern Georgia district into their column this November.

Former Rep. Denise Majette (D-Ga.), who lost a Senate bid against now-Sen. Johnny Isakson (R) in 2004, said Tuesday that Thomas has to be considered a serious threat to Barrow.

“Regina certainly has a strong base of support in the Savannah area,” Majette said. “Democratic primaries in Georgia over the last several cycles have seen more African-Americans voting … and certainly there are people all over the state that would like to see a woman representing Georgia in Congress,” since the delegation is all male.

Republicans meanwhile are just excited that Barrow looks to be in for a fight on July 15.

“I think this will force Mr. Barrow to come out on a lot of positions,” said John Stone (R), a former Congressional aide to the man who Barrow beat in 2004 and 2006, former Rep. Max Burns (R). Stone, who is considered the leading Republican candidate in the 2008 contest right now, said that Barrow, a moderate who affiliates with the Blue Dog Democrats, will now have to swing left in the primary on issues like taxes and the Iraq War. And that could hurt him in the general election.

Referring to the massive lead in cash on hand that Barrow reported in his latest Federal Election Commission report, Stone added that “the No. 1 thing this has done is it means that John Barrow cannot sit on that $1.3 million until Labor Day.”

Having another Democratic candidate cut into Barrow’s war chest would be good news for the Republicans since Stone leads the announced GOP candidates in cash-on-hand totals with a mere $43,000 as of March 31.

But the idea that Barrow could actually be knocked off in the the Democratic primary is what has Republicans especially giddy.

“This race went from not on the radar to on the radar within seconds” once Thomas entered the race, one Capitol Hill Republican said.

In an interview Tuesday, Thomas said she isn’t concerned about creating a potentially hobbling primary fight in a district that the Democrats won by just 864 votes in 2006.

“Maybe the incumbent should have concern with that number, but not me,” Thomas said.

Thomas, a Savannah native, said that despite announcing her intention to run for Congress just two weeks before the state’s filing deadline, she has long had her eye on a Congressional seat.

“I’ve been watching national politics for a very long time, and after serving 12 years in the Georgia General Assembly it’s time for me to move to the next level,” said Thomas, whose entire Savannah-based state Senate district falls within the 12th Congressional district.

She said she is in the race to give the voters a choice in a year when the electorate has proven to be particularly engaged in national politics.

In this year’s Democratic presidential primary, 50,066 12th district voters came out to vote for Sen. Barack Obama (Ill.) and another 20,292 voted for Sen. Hillary Rodham Clinton (N.Y.). (Barrow, by the way, has endorsed Obama in the presidential campaign.)

Thomas said that she didn’t think Barrow should just cruise to the Democratic nomination this year as so many unchallenged incumbents do every cycle.

“It’s for the people to decide whether they are pleased with what they have or whether they want to try something different,” she said.

Thomas conceded that Barrow will surely have the larger war chest in the primary race, but she estimated that she would not need more than $500,000 to run the kind of grass-roots campaign she said has made her successful in Savannah.

Although the district is about 45 percent black, Thomas said she expects the Democratic primary will come down to more than simply the skin color of the candidates.

“We’re bigger than that. We’re beyond that,” she said. “It’s not to me a black and white issue. It’s a people issue.”

Thomas did say that she is seeking support for her campaign from the Congressional Black Caucus and black leaders around the state.

“I think it would be wise on my part to take a trip to Washington and say ‘hi’ to the Congressional Black Caucus and let them know who I am and what I’m all about,” she said.

Regardless of how much outside help Thomas picks up in the coming months, Majette said Thomas’ grass-roots campaign style can certainly be effective.

“The person who has the most money is not necessarily guaranteed to win, and we’ve seen that in Georgia and how that’s played out on both the Democratic side and Republican side over the last several election cycles,” Majette said. “Neither of the candidates in this race is going to take the vote for granted, and that’s a good thing. I think they are both going to get out there and work hard and present themselves and deal with the issues and people will have a real choice to make, which I always think is a good thing.”

Barrow spokeswoman Jane Brodsky said Tuesday that “Congressman Barrow is going to keep doing what he’s been doing: working hard to help families in the 12th district of Georgia as their Representative in Congress.”