WASHINGTON -- It's unprecedented, the experts say: The volume and audacity of distortion, deception and truth-stretching in this year's presidential campaign has political fact-checkers busier than ever in their pursuit of the truth. But whose truth, precisely? And, in the context of a bitter campaign, does the actual truth -- and the responsibility of a politician to tell it -- really matter?
The question hangs over every modern campaign, and of course lying and truth-stretching have abounded in politics throughout U.S. history. But there are differences this time around. The convention speech last week by GOP vice-presidential nominee Paul Ryan may have brought the conversation into focus, but his carefully parsed words are hardly the only ones in the political arena that make people wonder if truth is becoming elastic.
"The partisans of the two parties might have a different attitude toward the truth," said Lionel McPherson, a professor of ethics and political philosophy at Tufts University. "It's possible one side doesn't care -- they think they can make those claims to their base with impunity, even if it's obvious those claims are false or misleading."
Recent changes in campaign-finance regulations have enabled super PACs -- outside political action committees bankrolled by wealthy Americans -- to spend huge sums on aggressive ads that ostensibly are beyond the control of the candidates' own campaign operation.
These proliferating third-party ads have been less accurate than candidate-sponsored ads, according to Kathleen Hall Jamieson, director of the University of Pennsylvania's Annenberg Public Policy Center. As a result, she said, "the sheer amount of deception is higher."
Another factor: Political ads are spread across ever-diversifying media, often resulting in highly targeted ads catering to specific interest groups rather than the electorate as a whole. That can produce many different shades of a statement -- and different interpretations of its truthfulness.
"What's different is that there are more messages and more fact-checkers, and naturally more conflict between them," said Bill Adair, editor of PolitiFact.com. "Our goal is not to get politicians to stop lying ... Our goal is giving voters vital information about what's true and what's not."
Adair's organization, a project of The Tampa Bay Times, has grown to encompass 36 reporters and editors. Full-fledged fact-checking operations also are conducted by The Associated Press, The Washington Post, FactCheck.org and others.
Yet Republican and Democratic campaign operatives seem undeterred by the fact-checking. They're eager to trumpet findings that discredit their opponents while dismissing findings that challenge their own ads and rhetoric.
Mitt Romney's pollster, Neil Newhouse, has indicated to ABC News/Yahoo News that his campaign won't be swayed by outside complaints of inaccuracy. "Fact-checkers come to this with their own sets of thoughts and beliefs, and you know what? We're not going let our campaign be dictated by fact-checkers," he said.
Officials from President Barack Obama's campaign insist they strive for accuracy but have not repudiated anti-Romney ads that were widely depicted as unfair. One example: a pro-Obama super PAC ad suggesting that a woman's death from cancer was linked to the layoff of her steelworker husband by Romney's firm, Bain Capital.
"We look at the facts. We vet what we say. We really do try hard to get it right," Obama campaign press secretary Ben LaBolt told ABC News/Yahoo News. "So there are some times when there are different sets of facts out there. The campaign highlights a set of facts. You may find a different set of facts and make that point."
Robert Loevy, a political science professor at Colorado College, said the level of truth-stretching and distortion in this campaign is "the worst I've ever seen" but expressed doubt that the fact-checkers have much influence on undecided voters.
"The electorate they're going after are not paying close attention," he said. "They're not likely to read the criticism in the high-towered political columns. All they're seeing the ads that intrude on them."
He attributed the spate of truth-stretching ads to increased polarization of the two parties, and the campaign strategy of trying to define an opponent in negative terms before the rival can do likewise.
"That's what's driving a lot of this -- the realization that negative advertising works," Loevy said. "These people would not say they're lying, but we all know they're stretching the truth, taking things out of context ... The more extreme, the better."
Does the truth matter? Willem DeVries, a philosophy professor at the University of New Hampshire, argues that it does.
"To the extent that elections are supposed to settle policy issues... truth (that is, real honest-to-goodness truth, not `truthiness') should matter, because decisions made on the basis of falsehoods tend to be bad decisions," he wrote in an email. "If you think that democracy really means that good policy is supposed to emerge from the wisdom of an informed electorate, then a campaign riddled with falsehoods is an abrogation of democracy."
Problems arise, DeVries said, when campaigns opt for emotional appeals or psychological manipulation regardless of the truth. "There can be a race to the bottom," he wrote, "for such techniques have proven themselves often highly effective."
His fellow UNH philosophy professor, Nick Smith, wonders if the American public is to blame for not calling out politicians when they do lie or deceive.
"Perhaps we do not hold them accountable because we have become so biased toward our own views that we view political discourse as a kind of ideological warfare where any weapon should be deployed," Smith said. "So if a politician gets caught in a lie, some do not see this as a character defect but rather an occupational hazard."
McPherson, the Tufts professor, suggests that a politician in office -- including Obama as sitting president -- should be held to higher standards of truth than a candidate seeking to gain office. "Challengers are desperate," McPherson said. "Who knows what desperate people will do?"
During the past week, both presidential campaigns have accused the other of wallowing in lies and deception. It has been a prominent theme in speeches at the Democratic National Convention.
"Tonight I want to talk to you about a scary subject for many, many Republicans," Illinois Gov. Pat Quinn said Tuesday. "I want to talk about facts."
He went on to assail the GOP claims, widely debunked by independent fact-checkers, that Obama was weakening the work requirement of federal welfare policy. The Romney campaign responded with a press release citing an assortment of independent fact-checkers who found fault with statements by various Democratic speakers.
On Wednesday, Democratic National Committee Vice Chairman R.T. Rybak took aim at Ryan's credibility, saying he has had "an increasingly exposed history of exaggerating or fabricating the truth."
"We can't have a person a heartbeat away from the president who can't look people in the eye and tell them the truth," said Rybak, the mayor of Minneapolis.
PolitiFact's Adair says both campaigns seem ready to push the boundaries on accuracy. "It's a classic strategy: Don't let the facts get in the way of a good campaign theme," he said. And even when evidence might be sketchy, "Both campaigns have certain story lines they're going to push."