"If you can get more affluent people, who are more geographically dispersed, to mail in ballots earlier, then you can focus your more geographically concentrated efforts on low-income and minority populations," he said.

The GOP ups its game

Regardless of how early voting may help campaigns streamline their efforts on Election Day and the hours immediately beforehand, there's no question that day-of get out the vote efforts remain as critical as ever - particularly in an election that's being billed as nail-bitingly close.

As with early voting, Republicans this year were dead-set on improving their turnout numbers from 2008, when President Obama swept even traditionally Republican states like Virginia and North Carolina.

"We started the ground game before we even had a nominee," said Kukowski. "We said, this is something that we're going to do. We're not going to make this mistake again; we're going tot have a ground game in place very early."

In order to get a head-start on the process, she said, the RNC opened up "victory offices" in battleground states in the spring, and the Romney campaign "moved in with us" once he was officially nominated.

According to Kukowski, these last few days of the GOP get-out-the-vote effort is the final leg of a process that's been in the works for months. In the summer, the campaign was in what it called its "identification phase," where it culled the list of targeted voters. Then they moved on to the early voting stage of get-out-the-vote, which involved "super Saturdays" aimed at reaching ever-increasing voter contact goals. All of that, she said, got the party into "fighting shape" for right now, when they'll be aggressively targeting the "low-propensity" voters they've been contacting for months.

"These people have heard from us, and they're going to hear from us several more times over the next few days. Between knocking on their door and making phone calls, you're recirculating them into the universe and you're contacting them again and again."

Kukowski says that between door knocks and phone calls, the campaign had made over 51 million voter contacts as of Friday. Between Saturday and the end of Election Day, they would have made four million phone calls, knocked on two million doors, and deployed 150,000 volunteers. The RNC is particularly confident in its presence in critical states like Florida, Virginia, and Ohio, as well as Wisconsin, where a strong ground game recently helped Governor Scott Walker defeat a recall election.

"On Election Day alone we estimate about two million contacts," Kukowski said. "When we're talking to the voters... they know that if they need a ride that we will provide. There is a process in place to get anybody that needs to get to the polls to the polls."

"A ground game unlike anything American politics has ever seen"?

Despite any gains in the Republican ground game, Democrats flat-out reject the notion that the RNC-Romney efforts could anywhere mirror the organization and infrastructure they say they've been building for years. In a conference call on Saturday, Obama campaign manager Jim Messina said that, as of the weekend, the campaign had begun to execute "the final phase of a ground game unlike anything American politics has ever seen."