Even as his comments were being questioned, Huckabee criticized Romney Saturday at campaign stops in Iowa for concocting parts of his past. "You are not going to hear me making up stuff about my biography," said Huckabee, who also referred to Romney's exaggeration of his hunting exploits: "I don't go around saying I was a lifelong golfer because I once rode in a golf cart when I was eight years old."

When a candidate is caught making a clearly false statement, embarrassment or ridicule often ensue — and over time a reputation can form. But the electoral rewards derived from stretching the truth or distorting a rival's record just as frequently outweigh the fleeting political costs.

"I would not say that the level of honesty or deception is better or worse than in past campaigns," said Brooks Jackson, director of Annenberg Political Fact Check, who has been truthsquadding political candidates since 1992. "It is a function of running for office that you want to say things that are pleasing to voters."

Some campaign operatives argue that candidates are becoming more cautious about their public pronouncements, for fear of being caught making a mistake. "I think candidates are being more careful," said Mike Gehrke, research director for the Democratic National Committee. He notes that the ease of retrieving information online has made it possible "to fact check at a much more granular level than ever before."

Responses by candidates to challenges on factual accuracy can be as revealing as their original statements. Rather than acknowledge that he had made a mistake about his father marching with Martin Luther King Jr., Romney argued over the meaning of the word "saw," saying that he had used it in a "figurative" sense without the intention to mislead. His aides put reporters in touch with eyewitnesses who claimed to have seen his father "hand in hand" with King. Contemporaneous newspaper reports showed that the two men were in different parts of the country on the date in question.

Giuliani has repeated questionable claims on the campaign trail, and even in his advertisements. A case in point was his assertion in October that his chances of surviving prostate cancer were twice as high in the United States as in Britain "under socialized medicine." He defended the statement as "absolutely accurate" even though his campaign was unable to produce a single peer-reviewed cancer researcher or epidemiologist who agreed with him.

Giuliani took a beating in many media outlets, but that may have been less of a concern for him than some other candidates, particularly the Democrats. The former New York mayor frequently draws applause from conservative audiences by citing attacks on his record from the New York Times.