It’s become something of a club, and not a particularly exclusive one at that: promising political figures with presidential aspirations knocked dramatically off course by marital infidelity. The latest member is Mark Sanford, the governor of South Carolina. In a bracing news conference June 24, the 49-year-old confessed to an affair with an Argentine woman following a bizarre six-day disappearance that grabbed national headlines when his own staff and family claimed ignorance about his whereabouts
