As the presidential race enters its critical final days, Mitt Romney’s campaign has drawn fire for two advertisements that it is airing in key swing states. The first, ”Who Will Do More?”, criticizes President Obama’s handling of the auto bailout; the second, ”Can’t Afford Another Term,” attacks Obama on welfare reform and deficits.

The ads have two key things in common: both were aired in unusual silence without the customary media announcement; and both make claims that are demonstrably false.

The ads raise the possibility that the Romney campaign is employing a tactic that poses a crucial challenge to the press: attempting to win over late-deciding swing voters who have not been following the race with false and even previously debunked messages.

The auto ad in particular, which has aired in Ohio since October 27, has drawn howls of protest from factcheckers and from the auto company referenced in the ad. The ad twists a poorly worded Bloomberg report that Fiat, the company that owns Chrysler, was planning to add Jeep production sites in China to suggest that Jeep production would be shifted out of the United States. “Obama took GM and Chrysler into bankruptcy and sold Chrysler to Italians who are going to build Jeeps in China,” the narrator intones.

The ad prompted Fiat to take the unusual step of reassuring its workers that no Jeep production would be shifted to China, and to denounce the ad as “so misleading that we had no choice but to offer a vigorous defense of our progress since bankrupcy.” The Washington Post’s Fact Checker gave the ad “Four Pinocchios,” its harshest rating. “When a campaign does not announce a television ad, it’s a good sign that it knows it is playing fast and loose with the truth,” wrote Kessler, the Post’s factchecker, in his assessment.

The second ad, which was released on Tuesday, revives the previously debunked assertion that President Obama has eliminated work requirements for welfare recipients. In fact, the policy offered states new ways to meet work requirements while receiving federal funding for welfare, but did not decrease or eliminate the amount of work required.

The Obama team, too, has run a recent unannounced ad, highlighting Romney’s statements about abortion rights—his expressed desire to reverse Roe v. Wade, for example, and to cut funding for Planned Parenthood. But since the ad consists almost entirely of direct quotes from Mitt Romney, deception is not an issue.

Aside from seeing these ads on television in swing states—which after all, is their target—there are several ways for reporters and other observers to uncover unannounced deceptive ads in the final days of the campaign. Video pages on both the Obama and Romney campaign websites display their respective campaign ads, including ads that the campaigns did not announce when they were released. Presidential ad trackers by USA Today and The Daily Beast also display recent ads that include spots by outside groups such as super PACs and nonprofits. Both the USA Today and Daily Beast interactives show assessments by third party factcheckers such as PolitiFact and FactCheck.org alongside the advertisements.

With the election hanging by a thread and only a narrow sliver of voters remaining undecided, dishonest last-minute ads may represent a strategic bet. The calculation seems to go like this: uncommitted voters often have little information about the campaign, and the media—particularly in swing states—will not bother to repeat previous fact-checks, or correct unannounced false messages quickly enough to prevent them from sinking in.

But everybody except pure partisans, it seems to us, have an interest in an honest debate, all the way to the wire. So it is up to reporters to watchdog ad claims down to the campaign’s final hours—and make sure that last-minute deceptions fail to hoodwink crucial undecided voters.

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