McDuffie, George, 1790–1851, American politician, b. Columbia co., Ga. He was a member of the South Carolina legislature and served (1821–34) in the U.S. House of Representatives, where he quickly became noted as an ebullient debater. He bitterly opposed the administration of John Quincy Adams and as ardently supported Andrew Jackson. McDuffie later broke with Jackson; he supported the Bank of the United States and also was a leader of the South Carolina group that advocated the doctrine of nullification. He was (1834–36) governor of South Carolina and served (1842–46) in the U.S. Senate.