Sanford's admission of an extramarital affair is just the latest sex scandal to rock the Republican Party. It follows Nevada Sen. John Ensign's confession last week to a similar transgression. And fellow Nevada Republican, Gov. Jim Gibbons, has been in hot water over salacious details regarding his ongoing divorce proceedings.
Of course, sexual indiscretions are hardly the property of one party. New York Gov. Eliot Spitzer resigned in disgrace last year in a prostitution scandal, and New Jersey's Jim McGreevey resigned as governor following his declaration that he is a "gay American." And John Edwards was carrying on an affair with a videographer as he was simultaneously campaigning for the Democratic presidential nomination last year.
For more on political sex scandals over the last decade, visit Political Junkie.
Ending days of speculation about his whereabouts, South Carolina Gov. Mark Sanford said Wednesday he had been "unfaithful to my wife" during a secret trip to Argentina.
"The bottom line is I've been unfaithful to my wife. I developed a relationship with a dear, dear friend in Argentina," said Sanford, a second-term Republican governor, former congressman and rumored 2012 presidential candidate. "It started as I guess many of these things do, a casual e-mail back and forth. Here recently over the last year, it developed as something much more than that.
"As a consequence I hurt her, my wife, Jenny, my boys ... I hurt a lot a lot of different folks," the governor said, adding that he has known the woman for about eight years, but their relationship intensified while he was on an economic development trip to Argentina a year ago.
Sanford said his wife and family have known about the affair for about five months, and that he and his wife are separated. She and the couple's children are living at the family beach house on Sullivan's Island.
Jenny Sanford said she asked her husband to leave home and stop talking to her two weeks ago. In a statement Wednesday, she said she needed a trial separation from her husband of nearly 20 years to preserve her own sense of dignity.
The governor said he is seeking his wife's forgiveness and wants to reconcile. Jenny Sanford's statement said he has earned a chance to resurrect their marriage.
Sanford said he was resigning his post as head of the Republican Governors Association, but he refused to answer questions about whether he would remain in office.
First lady Jenny Sanford had told reporters she did not know where her husband was during his absence, which began last Thursday and included the Father's Day weekend. When questions persisted, Sanford's staff released a statement saying the governor was hiking on the Appalachian Trail.
Wednesday morning, The State newspaper of Columbia, S.C. reported that Sanford had arrived at Atlanta's airport on a flight from Argentina.
The governor told the paper he decided to go to Buenos Aires at the last minute, rather than going hiking. He said he wanted to clear his mind after a difficult legislative session.
Sanford said he was alone on the trip and declined to give any additional details about what he did other than to say he drove along the coastline.
On Monday, a state legislator raised questions about Sanford's whereabouts after hearing reports from security officials that the governor could not be contacted. The governor's spokesman, Joel Sawyer, said Sanford wanted to get away to clear his head after the legislative session, during which he lost a key battle. Jenny Sanford said Tuesday, "Leave us to our privacy."
The governor has long been known as a loner — bucking GOP leadership during three U.S. House terms and casting the only dissenting vote on Medicaid coverage for some breast and cervical cancer treatment.
But past vacations never left Sanford completely out of touch, said Chris Drummond, Sanford's former spokesman. At worst, Sanford would call in daily or would respond to voice mails.
Who was in charge became the political and practical question.
Essentially, Sanford's staffers said they would decide whom to call if an emergency popped up and the governor couldn't be reached. South Carolina's Constitution says a temporary absence would give the lieutenant governor full authority in the state. But the temporary absence has never been defined.
Senate President Pro Tem Glenn McConnell, a Charleston Republican, said the state's law needs to be clarified. He said residents want important decisions to be made by elected leaders.
"In an emergency," he said, "it should be those people who consult with staff to make a decision and not the other way around."
Sanford served in the U.S. House for three terms before honoring a term limits pledge and leaving office in 2001. In 2002, he defeated incumbent Democrat Jim Hodges by 4 percentage points to become governor, and he won re-election in 2006, beating Democratic state Sen. Tommy Moore.
As governor, Sanford has had seemingly endless run-ins with the GOP-dominated Legislature, once bringing pigs to the House chamber to protest pork-barrel spending. He also put a "spending clock" outside his office to show how quickly a proposed budget would spend state money.
From WFAE in Charlotte, N.C., NPR staff and The Associated Press