In his very first television advertisement last year, Mitt Romney highlighted the nation’s dire unemployment crisis, its record number of home foreclosures and the rising national debt, and showed video of President Obama delivering this arresting remark: “If we keep talking about the economy, we’re going to lose.”

There was one problem: the quotation was taken so wildly out of context that it turned Mr. Obama’s actual meaning upside-down. The truncated clip came from a speech Mr. Obama gave in 2008 talking about his opponent, Senator John McCain of Arizona. The full quotation? “Senator McCain’s campaign actually said, and I quote, ‘If we keep talking about the economy, we’re going to lose.’ ”

PolitiFact.com, the Pulitzer Prize-winning fact-checking Web site, rated the advertisement “Pants on Fire,” its most deceptive rating possible, but it achieved what the Romney campaign had hoped: people started talking about the sluggish economy and how Mr. Obama’s campaign promises had fallen short. And it set the tone for the campaign that followed, which has often seemed dismissive of fact-checkers.

“We’re not going let our campaign be dictated by fact-checkers,” Neil Newhouse, the Romney campaign’s pollster, said this week during a breakfast discussion at the Republican National Convention in Tampa, Fla., that was sponsored by ABC News and Yahoo News. He said that fact-checkers brought their own sets of thoughts and beliefs to their work, and that the campaign stands behind its ads.