From CREW, March 21st, 2010:

Mark Sanford (R-SC) was elected governor of South Carolina in 2002 and was reelected in 2006. Under the state’s term limits law, he cannot run for reelection in 2010.

Charges:
Abused his office for his personal benefit and the benefit of his friends
Violated campaign finance laws by failing to report in-kind contributions and improperly converting campaign funds for personal use
Subordinated his responsibilities to his pursuit of an extramarital affair
Endangered his state’s economy by threatening to refuse stimulus funds