Mitt Romney’s latest television ad has two messages.

The obvious one is that the former Massachusetts governor is a family man. The less obvious one is that former House Speaker Newt Gingrich (Ga.), Romney’s main rival for the Republican presidential nomination, well, isn’t.

“I think people understand I am a man of steadiness and constancy,” says Romney in the ad. “I don’t think you are going to find somebody who has more of those attributes than I do.”

In case you missed that point, the old footage of Romney, his wife, Ann and their kids that plays throughout the ad serves as a visual reinforcement of it. (Sidebar: How is it that politicians always have scads of old pictures/movies of their families looking cute?)

Gingrich is, not surprisingly, not mentioned by name in the ad. But, it doesn’t take a political genius — which we are definitely not — to surmise that Romney putting his family front and center in the ad (not to mention on the campaign trail) is meant to remind Republicans of Gingrich’s turbulent personal past.

Gingrich has been married three times and, in the late 1990s, acknowledged engaging in an extramarital affair with the woman who became his third wife.

Gingrich has done his damndest to avoid talking about his marital past on the campaign trail and, when forced to answer questions about it, has given a pat answer: The past is the past and this election is about the future. (An example: “There are things in my life I’m not proud of, and there are things in my life I’m very proud of,’ Gingrich told the New York Times in February.)

And, polling suggests that Gingrich’s past doesn’t matter much to voters. At least not yet.

In a new Washington Post-ABC News Iowa poll, almost eight in ten likely Republican caucus-goers said that Gingrich’s “marital history” was not a factor in their vote while 16 percent said it was a major reason for them to oppose Gingrich and one percent said it was a major reason to support him(!).

That same poll shows that 25 percent of likely Iowa caucus-goers believe that Gingrich best represents the core values of the Republican party as opposed to 12 percent who say the same of Romney.

A New York Times-CBS Iowa poll provides a bit of a counterweight; asked which candidate “most represents the values you try to live by”, 11 percent said Gingrich did as compared to 19 percent who said the same of Romney.

There is an argument to be made when looking at these numbers that it’s not that Republican voters don’t care about Gingrich’s marital past, it’s that they don’t know about it. Gingrich has been out of elected office for more than a decade and for the non-political junkie class, out of sight means out of mind.

Educating voters on Gingrich’s past — beyond the subtle contrasts Romney is trying to draw in his new ad — is a very dangerous game though.

Personal problems tend to only directly impact races when they are either a) unfolding in the midst of the campaign or b) have some sort of “new” news that makes them relevant to voters.

A classic example of “A”: Revelations that Florida Rep. Mark Foley had sent explicit messages to underage House pages. The story broke in the fall of 2006 even as the Florida Republican was trying to win re-election. The scandal became so massive that Foley ultimately resigned his House seat.

A classic example of “B”: In the 2004 Illinois Democratic Senate primary, presumptive frontrunner Blair Hull’s campaign imploded when his divorce records were unsealed — records in which his ex-wife described him as a “violent man”. Although the divorce was six years old, it didn’t matter. .

Neither “a” nor “b” apply to Gingrich’s personal past. There is not all that much “new” to the story, which makes it tough for Romney or any of his other rivals to bring it up and not risk being pilloried for trafficking in the sort of politics that people say they abhor. (Remember that the debate moderators at the CNBC debate earlier this fall were booed for bringing up the sexual harassment allegations against businessman Herman Cain. And we know how that turned out.)

Beyond ads like this latest one by Romney that seek to raise the “personal as political” idea with the lightest of touches, don’t expect to see anything more about Gingrich’s past on television in the final month before the Jan. 3 Iowa caucuses.

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