Bruce Oppenheimer

Until Tuesday, Barack Obama was winning the race for the White House in Hamilton County.

The Illinois senator garnered about 4,000 more votes than Sen. John McCain, R-Ariz., in the county’s two-week early voting period.

“That’s partly a sign of intensity of support,” said Bruce Oppenheimer, a political science professor at Vanderbilt University. “If your supporters are really intense, they’re more likely to vote early.”

On Election Day, however, Sen. McCain won about 21,000 more votes than Sen. Obama in the county, preliminary results from the Hamilton County Election Commission show.

In two of Hamilton County’s neighboring counties — Bradley and Georgia’s Catoosa — early voters and Election Day voters cast ballots overwhelmingly for Sen. McCain. And in those counties, unlike Hamilton, early voters far outnumbered those who came to the polls Tuesday.

The early turnout was about the same in 2004, said Fran Green, elections administrator for Bradley County, where twice as many voters came to the polls early or voted absentee as did on Election Day.

“People are just used to voting early here,” she said.

Doug Bachtel, a demographer at the University of Georgia, said there are many reasons why early voting was a big draw this year, a key one being that lines were shorter in many locations.

“Most modern-day Americans will tell you they’re strapped for time,” he said.

But the lines in Bradley County, Ms. Green said, were actually longer during early voting than on Election Day because so many more people voted early.

In Georgia, more than half the voters who cast ballots statewide participated in early voting, according to the Georgia secretary of state’s Web site. In Catoosa County, early voters outnumbered Election Day voters 3-to-2.

Likewise, Dr. Bachtel said some people who wouldn’t be able to come to the polls Tuesday got the chance to vote in Georgia’s early voting period, which started Sept. 22 and ended Oct. 31.

But, he warned, the popularity of early voting may have happened only because of this year’s presidential contest. He said the real test will come in two years, during Georgia’s and Tennessee’s gubernatorial races.