Early in-person voting has begun in Iowa, the first swing state to open polling sites.

Residents of the battleground state can now vote in person at their local county auditors' offices or turn them in by mail. Some areas will offer additional satellite locations.

At the Polk County Auditor's office in downtown Des Moines Thursday morning, a line of voters stretched down the block as the door opened.

Peter Clay, 62, was among the many supporters of President Obama. He says he's volunteered for the campaign on his days off from his job as a zookeeper.

"It's important to have a lot of folks showing up today because it shows there's passion and energy in this campaign," Clay says. "This is our first chance to show how much we care about the outcome and to demonstrate we want this president in office for another four years."

Democrats also seemed to dominate as Johnson County opened its polls in Iowa City.

Victoria Walton, a librarian in Iowa City and an Obama supporter, says she doesn't see any reason to hold off until Election Day.

"I'm very concerned about the election, and wanted to place my vote as soon as possible," she says. "I've already decided and the debates are not going to change my mind in any way. I've been listening carefully and thinking about this a long time."

Aleta Alexander, 63, of Waterloo in eastern Iowa, was among several voters who said they were volunteering for the Obama campaign.

"I voted for him in 2008 because I thought for sure he was the president that was for all the people — not just blacks for whites or whatever but for everybody," she says. "And I still believe that. So that's why I'm voting for him again."

There were Romney supporters, even if they were a bit harder to find.

Virginia Sourbeer of Des Moines, a retired state legislative staffer and former teacher, describes herself as socially moderate. But she says she's worried about the federal budget and spending in programs like Medicare and Social Security.

Sourbeer says she trusts Romney more when it comes to the economy.

"I just think that his background, for one thing, and his record in Massachusetts, that he dealt with difficult economic times there, that he'll deal with the issue," she says. "Because we've had somebody who will not deal with the issue the last four years."

The Republican National Committee's Iowa spokesman, Tom Szold, says Republicans have intentionally held off on most efforts to promote absentee voting until this week. He says they believe Romney voters will show up on Election Day if not before.

"It's common knowledge that the Democrats are ahead of us in this," he says. "They start much earlier and they focus largely on their base. And we think that's because they're basically worried that their base is not going to turn out on Election Day."

But Erin Seidler, President Obama's campaign spokeswoman in Iowa, says promoting early voting just makes sense.

"We have 40 days to vote in Iowa. Why you would let any one of those days go by without getting folks to the polls is surprising to me," Seidler says.

The Obama campaign has pushed early voting across the country, urging Iowans in particular to "Be the First" to vote for the president.

Democrats have requested the overwhelming majority of absentee ballots in Iowa. But Republicans have an 18,000-person lead in voter registration.

Polk County Auditor Jamie Fitzgerald says Democrats have a longer track record of working to get out the early vote.

"Recently Republicans have started doing it," he says. "So the numbers are going to come a little bit closer. But the Democrats have been known for a lot of shoe leather, and working early."

Iowa is among more than 30 states that allow early voting.

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