For some beleaguered voters, it was their fourth trip to the polls to vote for the Senate seat in this grueling race that has attracted a seemingly endless list of political heavyweights, gobs of advertising and hoards of volunteers from both camps.

Georgians already have had four chances to cast ballots to help decide the Senate race: July's primary, August's primary runoff, the November general election and Tuesday's election runoff. The runoff was forced when Chambliss fell short of crossing the 50 percent threshold in a three-way race with Martin and a Libertarian candidate.

Secretary of State Karen Handel did not predict turnout for the contest, but Georgia's last Senate runoff in 1992 attracted about 1.2 million voters - roughly half the turnout in that year's general election.

Some 3.7 million people cast ballots in this year's general election, and both sides have since tried to keep voters' attention with a barrage of ads and visits by big-name politicians including former President Bill Clinton and Alaska Gov. Sarah Palin.

Both candidates have tried to play to their base to encourage voter turnout.

Chambliss has vowed to prevent a Democratic "blank check" in Congress, noting that the party is two seats away from a 60-seat Senate majority that could block GOP filibusters. Martin, for his part, has vowed to shepherd President-elect Barack Obama's political agenda through the Capitol.

Voters casting ballots for both candidates seemed to echo the candidates' arguments.

Willie Brigham, 70, a custodian in Savannah, said he turned out to the polls to help Obama push his agenda through the Senate.

"I feel he's going to help out the one who already won," said Brigham. "I just think if they have the 60 seats, they'll have a little more strength, a little more pull."

Aaron Alexander, a 24-year-old actuary voting in Atlanta, said he cast his ballot for Chambliss to prevent Democrats from expanding their majority.

"I wanted to come out to vote today because I don't want the Democrats to get 60 seats in Congress and I voted for Saxby Chambliss," he said.

Martin, for his part, has acknowledged he faces a close contest. In a campaign event with rap stars on Monday night, he exhorted his supporters to brave Tuesday's chilly weather to cast their ballots.

"You're not looking at Landslide Jim," he said. "It's going to be real close. This election is about who wants it the most - who wants change."