First, it is arguably the most competitive of the eight or nine battleground states that figure to decide the race. Second, early voting began Oct. 2 in Ohio, and both Republicans and Democrats have been racing to bank as many ballots as possible there before Election Day.
By the time polling places open their doors Nov. 6, experts estimate, as many as 35 percent of voters - tens of millions of people nationwide - will have already cast ballots, by mail and in person.
The use of early voting has risen dramatically. Some 33 percent of the 131 million votes for president in 2008 were cast before Election Day, up from about 15 percent in 2000.
This has turned the traditional get-out-the-vote push from a preoccupation of the last 72 hours of a campaign into an elaborate 45-day operation, staged according to the different dates and rules for early voting in key states.
"We've moved from identifying voters to chasing absentee ballots and encouraging early voting," said Rick Wiley, Republican National Committee political director, noting that the effort could mean the difference in a close race.
About 85 percent of ballots in Colorado will be cast early, Wiley predicted, and 75 percent of those in Nevada, another battleground. Up to 75 percent of Florida's votes could also be cast early, he said.
"The tactics don't change much," Wiley said. "You're still knocking on the door - but it may be that the voter you persuade has a ballot on the kitchen table and you can get them to vote right there."
The absentee-ballot push is playing out in Pennsylvania, where about 95 percent of ballots will be cast Nov. 6. On their way to contacting 3.5 million voters by phone or canvass, Republicans in the state have built up an advantage of nearly 16,000 in the number of absentee ballots requested: 82,054, to 66,278 requests from Democrats.
In Ohio, Democrats have an edge over Republicans among voters requesting absentee ballots, though not many have been returned yet. Of 691,000 people who have requested absentee ballots there, 30 percent are Democrats and 24 percent are Republicans, the rest unaffiliated.
So far, Republicans lead in absentee-ballot requests in Florida and North Carolina, while Democrats have the advantage in Iowa early voting.
Four years ago, Obama built up such big leads among early voters that he was able to win Colorado, Florida, Iowa, and North Carolina despite losing in those states on Election Day. Republicans are determined to stop that from happening again.
"He will not have the same early lead this year," Wiley said.
Jeremy Bird, the Obama campaign's field director, vows his team is ready.
"Are they better than John McCain? Sure," Bird told the Associated Press. "Are we better than Barack Obama in 2008? Absolutely."
New Jersey has moved to a "no excuse" system. Voters could begin applying for absentee ballots Sept. 22, and can do so until one week before Election Day.
To get absentee ballots in Pennsylvania, voters must state a reason they will be absent from their municipality Nov. 6, or attest that a disability keeps them from the polls.
Harrisburg - where this year's big battle was over requiring voters to furnish photo ID - has seen no serious push to legislate early voting.
"We are an extremely anti-reformist state and slow-moving on almost any advance you can name," said Terry Madonna, political scientist at Franklin and Marshall College. "The legislature and the political parties are risk-averse."
Contact Thomas Fitzgerald
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