Presidential campaigns hire a small army of people who quietly spend hours bent over file cabinets and microfilm, searching through tax records, divorce decrees, parking tickets and college papers.
Opposition research, or "oppo," as it's called, is a multimillion-dollar business with investigators, consultants, pollsters and political activists — all combing through candidates' backgrounds.
"You need to define yourself as a candidate and define your opponent to the voters," says David Bossie, an investigator who has researched the backgrounds of Bill Clinton and John Kerry. "And if you can be the person who defines your opponent — as opposed to your opponent defining him- or herself — you can win."
Bossie, who heads a conservative political organization called Citizens United, says, "Opposition research can be incredibly expensive... hundreds of thousands of dollars during a campaign cycle for president. And campaigns that take the campaign seriously will make that investment, because that investment will pay enormous dividends and have the opportunity to have just catastrophic impact on your opponent."
Jason Stanford certainly knows that. He has been doing opposition research since 1994, when he was hired by Texas Gov. Ann Richards to peer into George W. Bush's background. He now has own firm specializing in background research for Democratic candidates.
He says that simply finding a past blemish is not always enough to change voters' minds.
"It has to be accurate. It has to be relevant," he said. Even though bringing up embarrassing news about relatives is common, voters dismiss those stories, Stanford says.
"What they do use to make their choices are things like your voting record, who you take money from, what your business record is, and whether or not you say one thing and do another."
Opposition research has become more prevalent and more potent with changes in technology and an overall coarsening of American politics.
"Opposition research is ubiquitous," Stanford says. "I've done it for races as small as city council in one-stoplight towns."
John Harris is a journalist who has covered politics in Washington for 20 years. He is also the author of The Way to Win: Taking the White House in 2008. He says that the turning point for oppo was the 1988 presidential race, when Vice President George H.W. Bush faced Massachusetts Gov. Michael Dukakis.
By the fall of 1988, Dukakis had a 17-point lead in the polls, based on his success in strengthening his state's economy –- a feat that he called the Massachusetts Miracle.
That year, the Republican National Committee, led by Lee Atwater, created an aggressive oppo campaign. Dozens of volunteers staffed three shifts around the clock to feed the then-burgeoning 24-hour news cycle.
The goal was to paint two distinctly different pictures of the two candidates — and that was exactly what candidate George H.W. Bush did, in August 1988 at the Republican National Convention in New Orleans.
"Should public school teachers be required to lead our children in the pledge of allegiance? My opponent says no — and I say yes," Bush said.
The GOP branded him as a soft-on-crime liberal with the Willie Horton ad, says conservative activist, Bossie.
"Michael Dukakis let Willie Horton out on a weekend furlough program that he supported and, of course, this murderer went on a rampage, and, of course, the rest is history. That really defined Michael Dukakis, and it really sunk his candidacy as well."
Four years later, in 1992, Democrats had learned their lesson. Candidate Bill Clinton created his own aggressive oppo strategy, this time with a twist: Rapid Response.
They used faxes, as quaint as that seems 15 years later.
Clinton Communications Director Jeff Eller told NPR back then that faxes were effective weapons on the campaign trail.
"What it does is, it allows you to respond within the same news cycle. We try to get things into the hands of the traveling press corps that travels with the president to get our side into the story."
The Clinton campaign took advantage of other new technologies as well — cell phones — and the first pagers that included text messaging. They'd send notes to reporters covering the elder Bush's campaign, suggesting: "Why don't you ask this? Get their response to X, Y or Z charge," Harris said.
David Bossie says the Clinton campaign set a new standard for oppo research.
"They were fantastic at it — they beat a campaign who was not as good at it," he said.
John Harris says that each new technological advance, such as blogs and YouTube, has changed they way negative information is gathered and distributed.
"What we've seen in presidential politics is that every successive election cycle, the news cycle speeds up," Harris said. "It's not yet clear to me how that's going to manifest itself in 2008, but it's obvious to me in some way there will be some sort of technological innovation that will once again accelerate the news cycle, and intensify this notion of politics as war."