John Randolph Thune (born January 7, 1961) is the Republican (Republican Party (United States)) junior U.S. Senator (United States Senate) from the state of South Dakota.

Born and raised in South Dakota, Thune attended college at Biola University in California before returning to his home state to obtain a graduate degree at the University of South Dakota. He worked as a legislative aide to U.S. Senator James Abdnor (James Abdnor) and served in the Reagan Administration in the Small Business Administration, before winning election to the House of Representatives (United States House of Representatives) in 1996. After three terms in the House, he unsuccessfully challenged Democrat Tim Johnson (Tim Johnson (South Dakota)) in the U.S. Senate race in 2002, losing by a mere 524 votes (0.15%). Thune was elected to the Senate two years later, defeating the incumbent Democrat, Senate Minority Leader Tom Daschle.