Republican presidential candidate Newt Gingrich likes to boast that he can easily mop the floor with President Obama in a head-to head debate.

Maybe, and maybe not.

Snappy debating skills such as those exhibited by Gingrich against his GOP rivals in the primaries are certainly an asset in any campaign.

But beyond debates, and qualifications and education and experience, it takes far more to win the White House. It also takes something many voters say Gingrich lacks – strong moral character.

As is now well known, the former House speaker was been married three times and has a history of marital infidelity.

“He carries more baggage than an airline,” shouts an ad being aired this week in South Carolina by a Super PAC supporting Republican frontrunner Mitt Romney.

Some of that old baggage is about to be unloaded again tonight when ABC New’s "Nightline" airs an interview with Newt’s second wife Marianne Gingrich. In excerpts released today by ABC, she accuses her husband of wanting to have what she called an “open marriage” – stay married to her, but continue to have a girlfriend. At the time, that was Callista Bisek, a Gingrich staffer who ultimately became his third and current wife.

"He wanted an open marriage and I refused." Marianne Gingrich says in the ABC interview.

According to ABC, Marianne described her ‘shock’ at Gingrich's behavior. She said she learned he conducted his affair with Callista ‘in my bedroom in our apartment in Washington.’”

She further noted in the ABC interview that the exchange took place while Gingrich, then the House speaker, was leading the charge against then-President Bill Clinton for his lack of moral character in the Monica Lewinsky affair.

Also, according to ABC, Marianne said Newt moved for the divorce just months after she was diagnosed with Multiple Sclerosis. She said Newt was there when the diagnosis was made,
"He also was advised by the doctor when I was sitting there that I was not to be under stress. He knew," Marianne said in the interview.

Gingrich divorced his first wife, Jackie, after she was diagnosed with cancer.

The second Mrs. Gingrich also told ABC that Newt began to plan a run for president at the time of the divorce and told her that Callista "was going to help him become president." Callista now campaigns at her husband’s side.

Out on the campaign trail last week in New Hampshire, Newt’s daughter from his first marriage, Kathy Lubbers, often appeared with him. At some rallies she introduced her father and his third wife to the crowd. It symbolically was meant to imply, if not say, that his daughter was ok with the divorce.

When word leaked Wednesday evening that ABC was about air the Marianne Gingrich interview, the Gingrich campaign put out a pre-emptive statement by his two daughters from the first marriage, Lubbers and Jackie Cushman.

“The failure of a marriage is a terrible and emotinal experience for everyone involved. Anyone who has had that experience understands it is a personal tragedy filled with regrets, and sometimes differing memories of events,” the statement said.

“We will not say anything negative about our father’s ex-wife,” the statement continued. “He has said before, privately and publicly, that he regrets any pain he may have caused in the past to people he loves.”

The ABC interview airs at a pivotal time for Gingrich’s resurgent campaign. In recent weeks, he has been able to sidestep the character issue and shift media attention by sharply attacking Romney as a ruthless venture capitalist who destroyed jobs.

More recently, he has criticized Romney’s 15-percent tax rate payment on investment income, lower than rates paid by average wage-earners.

Latest polls suggest the attacks are working. They show Gingrich gaining ground on the former Massachusetts governor as the candidates race down to Saturday’s South Carolina primary.

If Gingrich survives this latest eruption on the moral-character front, and somehow emerges the GOP nominee, he will get his wish to debate President Obama. And his deft verbal gymnastics might score some points in the sparring.

But keep in mind that the presidential debates in the fall are the only time the voters get to assess the two candidates side by side. And in that assessment, they not only evaluate who presented his case more effectively and confidently, but also subliminally take a measure of the men as persons.

And when they look at Obama, most will see what appears to be a solid family man with one attractive wife and two growing daughters. What will they see when they look at Gingrich? After all, for most Americans, the presidential vote is their most personal vote.

Richard Benedetto is a retired USA Today White House correspondent and columnist. He now teaches politics and journalism at American University and in The Fund For American Studies program at Georgetown University.