In Mark Sanford race, a test of how much infidelity matters in South

There's an old saying in the South: "I might shoot you, but I'll pray over you when I'm done."

Whether it reflects how conservative women voters in South Carolina feel about Mark Sanford is at the heart of a hotly contested election for a US House seat in Charleston. Mr. Sanford, the Republican nominee, is seeking electoral redemption for lying in 2009 while governor, saying he was leaving the governor's mansion to hike the Appalachian trail but instead flying to Argentina for a tryst with a mistress.

Tuesday's special election in the First Congressional District pits Sanford, a three-time congressman and two-time governor, against Democrat Elizabeth Colbert Busch, a shipping executive and sister of Comedy Central parodist Stephen Colbert. The matchup has a variety of national tendrils, not the least of which is the unusual opportunity for Democrats to gain a foothold in the deepest South, where the rarified Old South still wafts through the magnolias and one can easily imagine the echoes of the Civil War cannon booms.

"If [Democrats] were to win this, it would be like sharks smelling blood in the water," says Charm Altman, president of the South Carolina Federation of Republican Women, in Sea Island, S.C.

The national buzz is big, centered on whether the man who changed for a generation the meaning of "hiking the Appalachian Trail" will be redeemed. The turnout, meanwhile, is expected to be relatively small, as most constituents, especially blacks and younger voters, tend to sit out special elections.

That dynamic, added to Sanford's infidelity, has put all the focus on Republican women – the largest voting bloc in the district. Many have said they have no intention of casting their vote for a philanderer who, upon his return to South Carolina, went before the TV cameras to tell all the world that his mistress was his "soul mate" knowing that his wife, Jenny Sanford, must have been watching. (The other woman, Maria Belen Chapur, has since become Sanford's fiancée.) It all hit a bit close to home for voters such as Sabrina Vegis of James Island, who said in a March interview with the Monitor that she's seen, in her own social sphere, similar behavior by "a certain kind of man" crush marriages and friendships.

"Both sides realize the important role of Republican women in this race, and right now the big story is whether Republicans are going to stay at home today," says Scott Buchanan, a political scientist at The Citadel military college in Charleston.

Democrats have poured more than $1 million, twice as much as the Sanford campaign, into the race, and Ms. Colbert Busch has appealed directly to women voters for support, much as the Democrats did in the national 2012 presidential campaign. Trying to shave away at a nine percentage point deficit in the polls, Sanford has reframed the debate, pulling statistically even with Colbert Busch in the waning days of the campaign.

Recognizing that the contest in this solidly Republican district is all about highlighting the flaws of a very vulnerable Republican, the Colbert Busch campaign has aimed its basic message – "Why would you want want to vote for this scum ball?" as Mr. Buchanan paraphrased it – at what historians call the fiscally conservative, socially moderate Southern belle, keen to remember and expunge injustice.

"I think Southern women have a history of being abused, and there remains a sense that injustice has been done in the South to women, and … that [Southern] women do not forget the recent past nor the distant past," says Bill Ferris, associate director of the Center for the Study of the American South at the University of North Carolina, Chapel Hill. "A woman who feels she's been betrayed, or things have been done that were not right or fair, more than ever feels empowered to speak out and take appropriate action in response to that injustice. The Southern woman is a rich and complex person, and this election certainly will reflect that."

Part of that complexity played out in an ad that appeared in the Charleston Post and Courier on Sunday, paid for by a consortium of Republican women, in support of Sanford. Ms. Altman, the Republican women's federation president, signed her name to it, although she says she had her doubts about Sanford before he won the Republican primary in March and the ensuing runoff early last month.

"One of the things I tell women who say they won't vote for Mark Sanford is that I’m one of those Bible-toting, gun-toting, blonde Republican conservatives, and I live with the Scripture, which says that all have sinned and fallen short of the glory of God, and ye who is without sin cast the first stone," she says in a phone interview. "Yes, there have been a lot of smart remarks, the 'Luv Guv' and such. But I'm my husband's third wife and he's my second husband, and we have a closet we don't look in. Everybody has something they wouldn't want the public to know. Everybody has sinned and gotten forgiveness."