As this election heads toward what looks to be a photo finish, there are really two presidential campaigns afoot. One is happening in public, on view in debates, campaign ads and big speeches. But there's a stealthier one, with private messages tailored to specific voters and delivered not in front of TV cameras but right to their mailboxes. It's called micro-targeting, and, according to author Sasha Issenberg, it allows campaigns to talk directly to the exact voters they need to win. Issenberg's new book, "The Victory Lab," about the science of winning campaigns, details the way the tactic has changed the face of modern politics in the past decade.
"They [the campaigns] will have a prediction of the likelihood that you are a gun owner. That's obviously a really sensitive issue. You don't want to misfire if you're a candidate and send something about gun control to someone you think owns a gun and vice versa. So the campaign can make sure when they're sending something about gun control it's only to someone they're very sure owns a gun," Issenberg said.
By doing that, Issenberg said, "You can, theoretically, have a different conversation with everyone on the block."
So how do the campaigns figure out what issues are important to which voters? Data. Reams of it. For years, consumer buying habits have been documented by companies who condense that information into databases and sell them, most recently to political campaigns.
They've discovered that if people who watch "30 Rock" and drink Molson, are most likely to be Democrats who vote frequently. Those who drink Coors Light and watch "NCIS"? are probably loyal Republicans.
Knowing this helps campaigns decide where to advertise. Republicans buy almost three times as many ads in college football telecasts as Democrats because that's where their audience is.
And micro-targeting is often as much about motivating a campaign's base as about finding an undecided voter.
"This is the big change in the way campaigns think in the last decade. It's far less about just changing peoples' minds and far more about modifying their behavior," Issenberg said.
And yes, there's an app for that.
The Obama campaign wants its supporters to knock on doors and get out the vote, but not waste time on those folks – say, registered Republicans -- who are unlikely to ever vote for President Obama.
So the Obama for America canvassing app uses little blue flags to show -- house by house -- where likely Democratic voters live, based on each resident's name, age, party registration and other data.
This kind of data-mining has also resulted in campaign ads popping up in new and surprising places -- for example, Obama ads in video games.
The Obama campaign's number-crunchers concluded that the presence of a teenager in the house helped predict support for him, Issenberg said, so this year, the campaign bought early-vote reminders in video games, hoping to reach the parents indirectly.
In the battle for the White House, there's no audience that is too niche.
Mitt Romney, for example, is trying to capture a tiny fragment of the electorate: those concerned with the spread of Lyme Disease. An official mailer sent to homes in an area of northern Virginia declared that the Romney-Ryan ticket is devoted to "getting control of this epidemic that is wreaking havoc on Northern Virginians."
It's not the first time that Romney, who has declared his love for data, has employed micro-targeting. In 2002, he won his 2002 race for governor of Massachusetts after he bought the list of HBO subscribers and tried to win them over.
"There's nothing about watching 'The Sopranos' that makes you more likely to vote for Mitt Romney, but it was a very good way of finding sort of upscale, suburban voters who were his target audience," Issenberg said.
An even smaller niche target is Minnesota beet farmers, whom George W. Bush went after in 2000, sending them a mailer that documented his support for an agricultural policy important to them.
"This wasn't something he talked about in the debates. It wasn't something they ever ran an ad about. But for tens of thousands of people in this one state he was trying to win, they got to the issue that those people cared about most," Issenberg said.
There's no evidence to show definitely that these tactics alone put candidates over the finish line. According to Issenberg, the single biggest clue to how you'll vote isn't what beer you drink but whether you're a registered Democrat or Republican.
But the small gains from small targets can add up and be significant, he said. A powerful tool, but one that should be used judiciously, Issenberg warned.
"The campaigns, even though they know they have the tools to really target specific messages to voters, are also aware that the costs of getting caught doing it, if they contradict themselves, are high."