GWEN IFILL: And back now to presidential politics with a report from a Midwestern swing state where votes are being cast, even before the candidates step up to the lectern for their first debate tonight.
Hari Sreenivasan has the story.
HARI SREENIVASAN: Iowa, the first state to caucus, is also the first battleground state to open precincts for early voting.~
Last week, on the first day when voters could cast their ballots at a voting booth, the lines were almost an hour long.
JAMIE FITZGERALD: We processed 596 voters at our counter yesterday over eight hours, which is six times the amount we did four years ago.
HARI SREENIVASAN: Jamie Fitzgerald is the Polk County auditor of elections. In 2008, he says a third of the voters in his county cast ballots early, either at precincts or by mail.
MAN: Stick it inside the secrecy envelope, seal it.
HARI SREENIVASAN: This time, he thinks the number of early voters could be even higher. The campaigns know it too, and both are factoring it into their strategies.
WOMAN: You probably already know that the voting has begun here.
HARI SREENIVASAN: For the past three presidential election cycles in Iowa, Democrats have pushed their supporters to the polls early, as a way to gain a lead before Election Day.
RAY BENTER, Obama for America Volunteer: Voting by mail gives us a sure vote. It also helps the voter in that they don't have to worry about getting to the polls in Iowa weather, which in November can be not good.
HARI SREENIVASAN: But this year, the Republicans are fighting for those early votes, too, according to O. Kay Henderson, the news director for Radio Iowa. She's been covering politics here for 28 years.
O. KAY HENDERSON, News Director, Radio Iowa: They are targeting voters who they might consider to be less likely to be Republican voters, maybe somebody who cast a ballot for the first time in 2010 in 20 years, and may have voted for a Republican congressman.
They're hoping to get those people to cast this vote in this 40-day window before Election Day to, as they say around here, bank the votes.
HARI SREENIVASAN: A recent Des Moines Register poll found less than 2 percent of Iowa voters were undecided, which means the campaigns could benefit from locking in votes early.
SABRINA FEST, Romney for President Volunteer: We know that the Democratic Party has a lot of early voters, so we're trying to get as many early voters as them.
HARI SREENIVASAN: Seventeen-year-old Sabrina Fest is one of many volunteers the Romney campaign says has helped them make more than a million phone calls. Keep in mind, Iowa has a population just over three million.
How many phone calls have you made just today?
SABRINA FEST: I'm not sure. They say the average is about 50 per hour, but I use two phones, so a little more than that.
HARI SREENIVASAN: According to social scientists, personal contact such as phone calls and door knocks can boost turnout by 3 percent or more.
But the campaigns know, in Iowa, nothing beats a handshake. Since May, the two presidential candidates have held 30 events across the state, with President Obama holding three times as many campaign stops as former Governor Mitt Romney.
Both vice presidential candidates have crisscrossed Iowa just in the past few weeks, a sign both parties still think they can win here. President Obama has taken a lead in recent polls. Still, he is not headed into this election with the same advantage he had in 2008, when he won the state by 10 points.
Two years ago, the Republican Party chipped away at the Democrats lead, and now claim almost 11,000 more registered active voters. Mitt Romney came in a close second here in the January caucuses. That's four years after he ignored, and lost, the state, also proof of how campaigning here can make a difference.
Republicans want to capitalize on that momentum.
O. KAY HENDERSON: In 2008, the Obama campaign had the organizational advantage in Iowa. In 2012, Republicans have stepped up their game. The Romney campaign and the Republican National Committee have committed a lot of resources here. They had done more by April than John McCain did in Iowa by election night.
HARI SREENIVASAN: But political support in Iowa doesn't simply rely on the sheer force of campaigning. There are more voters registered without party affiliation in Iowa than there are Republicans or Democrats.
Many Iowans measure the candidates independent of their party, voters like 19-year-old Charlie Comfort, who we met at Smokey Row Coffee company in Oskaloosa.
CHARLIE COMFORT: I want to meet with them one-on-one. They have the opportunity to come here. I want to meet them.
HARI SREENIVASAN: Comfort has already won a seat on the local school board. He volunteered for then Senator Obama's campaign in 2008, but has since switched his allegiance to Romney based on what he considers a broken promise by the president.
CHARLIE COMFORT: I feel he's almost kind of stiffed some of the voters on a couple of issues. The biggest one for me is education, obviously, because I'm on the school board, and I feel he's not paying near as much attention as he should towards the educational system.
HARI SREENIVASAN: What Comfort cares about has instead been drowned out by the campaigns selling competing visions to Iowans.
The differing philosophies on job creation, the economy, and the role of government are clashing in Newton, Iowa. This is the birthplace of the washing machine, where Maytag made its home for decades. In 2007, when the plant was shut down, Newton lost about 1,800 jobs and millions from the local economy.
CHAZ ALLEN, Mayor of Newton, Iowa: Our main focus for Newton right now is getting people back to work, as well as Jasper County. So, I mean, our focus is -- is employment.
HARI SREENIVASAN: Chaz Allen has been mayor here for nine years, we caught up with him after a charity motorcycle ride.
He says two companies have moved into Newton, building windmill towers and turbines and employing almost 1,000 people. Allen's support is squarely behind President Obama, thanks to the wind energy tax credit designed to help these businesses grow.
CHAZ ALLEN: Mitt Romney's message is to get rid of the wind production tax credit. Well, that's big here, because we have got
TPI and Trinity both producing wind turbines and wind towers, and that's a critical factor for us to keep those plants moving past 2013.
HARI SREENIVASAN: O. Kay Henderson says these single issue voters add up quickly in such a small state.
O. KAY HENDERSON: If Iowa does again come down to a few thousand votes, these sort of narrow-cast issues can have a huge effect. And so that is why you see the Obama campaign pushing this so hard, because the wind energy industry has about 7,000 or 8,000 workers in Iowa.
HARI SREENIVASAN: Then there is the fight in plain sight.
NARRATOR: Romney would jeopardize thousands of jobs and knock the wind out of Iowa's economy.
MITT ROMNEY, Republican Presidential Candidate: A prairie fire of debt is sweeping across the nation.
HARI SREENIVASAN: The negative ads on almost every channel, every night.
STEVE BUMP: I mean, it's almost the ads border on being vulgar.
HARI SREENIVASAN: Steve Bump has run a fireplace business in the Des Moines suburbs for 38 years. He knows fall is when people think about snuggling up to a warm fire, and more important for him, when they make buying decisions.
STEVE BUMP: If I'm selling romance and entertainment with my product, and I am -- I'm selling a product that is fun to have, a fireplace, a barbecue grill -- I don't want that customer to have all these negative thoughts in their mind about this ad that preceded me.
HARI SREENIVASAN: Bump says super PAC-funded political ads are clogging up the airwaves. Those campaign ads push his commercials off prime time and all his ads now cost 25 percent more.
STEVE BUMP: I'm probably seeing no less than 30 to 50 negative ads between 6:00 and 10:00, and that's watching the same channel.
HARI SREENIVASAN: At Oktoberfest in Amana, Iowa, Tina Wing has already heard too much from both sides. The campaigns also must contend with a sense of election fatigue from voters.
TINA WING: I think I get calls every single day from every state across the nation. I feel like there is a voting booth for a reason, that it's my business and nobody else's.
HARI SREENIVASAN: But it won't keep the campaigns from trying to reach her for another 34 days.