Updated

Volunteer Jeff Johnson estimates he's walked 140 miles knocking on doors for the Romney campaign.

"I hit Republicans or undecideds," he says, explaining that he's not really doing it to persuade anyone. His goal is to be certain that no Romney supporter fails to cast a ballot.

"Nobody stays home and if they say, 'I'm going to vote in person,' I say where are you going to vote? So I know exactly where they are going to vote. And then I urge them don't forget."

With a razor-thin margin in the polls, mobilizing the support base has rarely been as important as it is in this election. And the ground game is probably most intense, and detailed, in the battleground of Ohio.

The campaigns have mined past voter records for data, not just on voter trends but for each specific voter. Using the latest technology they can learn about what matters to that individual and get that information to the volunteers headed into the neighborhoods.

"So that when we knock on your door, we know as much information about you as possible. We've already created a relationship with you, that relationship has been cultivated and built upon over the course of the last few years," said Ohio Democratic Party Chairman Chris Redfern.

"We know who you are, where you live and how you voted. But more importantly to us, we have an expectation of how you will vote in this next election."

Democrats in Ohio enjoy the advantage of an apparatus that was renovated, tested and energized in the recent campaign that ultimately repealed Republican Gov. John Kasich's law that limited collective bargaining for state employee unions. "It's a huge advantage. It's one of the things that isn't focused on by the national media because at the end of the day, it was a state issue," claimed Redfern.

Obama supporter Jim Bishop said he is out walking the neighborhoods of Columbus and knocking on doors three nights a week. "We're about ready to harvest," he said. "Our job just before election is to get out the vote."

That does not mean Republicans are somehow at a deficit with energized volunteers. This week alone they have knocked on 292,000 doors. Through the campaign, they have made personal contact with 5.8 million voters in the Buckeye State.

For every call or knocked door, the campaign volunteer knows the name and key issues for that targeted voter. "There is no hiding under a rock. You would have to be in a different universe if you have not received some means of voter contact, whether it's a phone call, door knock, ads," said Chris Maloney, spokesman for the Romney campaign in Ohio.

Between the campaign motorcades stopping traffic and the intrusions into their homes, every voter in Ohio knows that the campaigns are interested in them, or at least their ballot. "I knew Ohio was going to be very, very important and we are all very intensely aware here," said resident Rich Northup at a Columbus coffee shop.

Lisa Rogers said, in a word, she is "annoyed" by the campaign assault. She and her husband have stopped answering their land-line telephone because it is always a campaign calling. "I've been decided on my candidate for a long time. So the phone calls and everything, nothing is going to sway me now," said.

For the beleaguered and badgered battleground state voters, there is a way to stop all the phone calls and door knocks: they can vote early. The campaigns are tracking each voter with such detail, they will know once they cast a ballot.