WASHINGTON - They say the first casualty of war is truth, and with the U.S. presidential election campaign now in bare-knuckled battle mode, "truth" is becoming a rallying cry.
Republican vice-presidential nominee Paul Ryan has been maligned by the media, political pundits and Democrats for the half-truths and exaggerations in his fiery address to his party's convention last week, even though such oratorical stretches are hardly a novelty in the heat of a tense, tight political race.
The pile-on continued on Sunday, as even a fellow Republican joined in.
"Paul Ryan, what he did in his speech, I think so stretched the truth," Matthew Dowd, chief political strategist for George W. Bush's 2004 re-election campaign, said on ABC's "This Week."
"The elements that he said about closing the GM plant which closed before Barack Obama took (office), about the Simpson-Bowles bill which he opposed and then all of a sudden he faults Barack Obama for. At some point, the truth should matter."
Obama officials, less surprisingly, also kept hammering away on a Democratic mantra given a new lease on life by Ryan's speech: Republicans lie.
Health-care policy proposals from Mitt Romney and Ryan are "built on a foundation of absolute lies," senior White House adviser David Plouffe said on ABC.
Stephanie Cutter, Obama's deputy campaign manager, called the Tampa convention "a week of personal attacks, empty platitudes" where "lying is a virtue."
Their message has been sharpened by a newfound enthusiasm for fact-checking not just by independent organizations but also by some of the biggest news outlets in the United States, particularly after Romney pollster Neil Newhouse told a breakfast meeting in Tampa last week: "We're not going to let our campaign be dictated by fact-checkers."
Newhouse was responding to questions about a Romney campaign ad that asserts — falsely, according to several impartial fact-checkers — that Obama has offered waivers to states that effectively gut the work requirements in the American welfare system.
In fact, the Obama administration memo gives states the flexibility to come up with better ways to find work for welfare recipients.
It's just the latest in a litany of cynical, deliberate falsehoods from the Republicans, says a longtime Democratic veteran of political conventions.
"This is the worst I've ever seen it; I have never seen claims as shameless and egregious as the ones the Republicans are making in 2012," Ed Espinoza said in an interview on Sunday.
"Anyone who's been watching for past three-and-a-half years knows they have obstructed, filibustered, delayed and voted against every single thing that has come up; they make no bones about it. And now they pin that on Obama? They say there hasn't been partisanship? Come on."
And yet the Obama campaign hasn't been blameless in terms of making false claims this election season.
Team Obama has run two separate ads this summer saying Romney has "backed a law that outlaws all abortions, even in cases of rape and incest." That's untrue.
Another ad from a pro-Obama group suggested that Bain Capital, the private equity firm founded and helmed by Romney for years, was responsible for the death of a steelworker's wife. The White House has refused to condemn the ad even though fact-checkers have.
There have been howls of protest from the left about the Romney campaign taking Obama's recent "you didn't build that" remarks wildly out of context; mockery of the phrase was a key theme of the convention in Tampa last week.
But the Obama campaign did the same thing with Romney's remarks in January that he likes "being able to fire people."
While Obama was suggesting government infrastructure also helps businesses succeed in his much-maligned comments, Romney was defending the free market system that allows people to shop around for goods and services if they're unhappy with the status quo.
Each campaign has their own, internal brigade of fact-checkers, so it's no mistake when a whopper ends up in a well-vetted campaign speech or a devastating television ad.
Indeed, campaign insiders say the falsehoods are often deliberate, especially when they think a message is resonating with voters — even if that message bears little resemblance to reality.
The Romney campaign, for example, has said the anti-Obama welfare ads have been their most effective, particularly among working-class white male voters, a difficult demographic for the president.
Women voters, meantime, favour Obama, so any suggestion that Romney is on the extreme right on abortion serves to fire them up.
In an age of constant social media updates and a fast-paced 24-hour news cycle, Americans tend to have short attention spans, said Espinoza.
"Even though independent fact-checking is readily available, people just aren't inclined to go looking for it," said Espinoza. "They tend to believe the last thing or the loudest thing they just heard, and campaigns know that."
Nonetheless, Republican fact-checkers are expected to be out in full force at this week's Democratic convention in Charlotte, N.C., ready to return fire with fire following last week's attacks on Ryan. As many as 50 Romney surrogates, including Florida Sen. Marco Rubio and South Carolina Gov. Nikki Haley, are descending upon the city in the days to come.
"They're going to hold Democrats accountable for any inaccuracies," Matt Mackowiak, a Republican strategist, said Sunday.
"Democrats seem to be desperately looking for something to run on because Obama's not running on his record. So maybe 'dishonesty' will be their new theme, their new attempt to deflect attention away from his record. Republicans are ready to counter that."
On one recent issue, anyway, Paul Ryan has all but admitted he fibbed — he said in a recent interview that he'd once run a marathon in under three hours, a remarkable feat. But he was forced to do a mea culpa when Runner's World magazine challenged him on it over the weekend.
"The race was more than 20 years ago, but my brother Tobin — who ran Boston last year — reminds me that he is the owner of the fastest marathon in the family and has never himself ran a sub-three," Ryan conceded in a statement to the magazine.
"If I were to do any rounding, it would certainly be to four hours, not three. He gave me a good ribbing over this at dinner tonight."