John Randolph Thune ( THOON; born January 7, 1961) is an American politician serving as the senior United States senator from South Dakota, a seat he has held since 2005. A member of the Republican Party, Thune has served since 2025 as Senate majority leader and Senate Republican leader. From 1997 to 2003, Thune served as the U.S. representative for South Dakota's at-large congressional district.
Born in Pierre, South Dakota, Thune is a graduate of Biola University and the University of South Dakota. First elected to Congress in 1996, he was reelected in 1998 and 2000 before running for U.S. Senate in 2002, narrowly losing to incumbent senator Tim Johnson. In 2004, Thune ran for Senate again and defeated Senate Democratic leader Tom Daschle. He was reelected in 2010, 2016, and 2022.
During his Senate tenure, Thune has served as the Republican chief deputy whip (2007–2009); chair of the Senate Republican Policy Committee (2009–2012); Senate Republican Conference chair (2012–2019); majority whip (2019–2021); and minority whip (2021–2025).
Thune was born in Pierre, South Dakota, on January 7, 1961. He is the son of Yvonne Patricia (née Bodine) and Harold Richard Thune. Harold Thune was a fighter pilot in the Pacific theater during World War II who flew the Grumman F6F Hellcat; he was awarded the Distinguished Flying Cross after shooting down four enemy planes. Thune's paternal grandfather, Nicholas Thune, emigrated to the United States from Norway in 1906; he partnered with his brother to run a chain of hardware stores in South Dakota. Nicholas Thune changed his last name to Thune from Gjelsvik because he was told by immigration officers that the name Gjelsvik was too hard to pronounce. Thune's maternal grandfather was from Ontario, Canada, and his mother was born in Saskatchewan.
Thune was a star athlete in high school, active in basketball, track, and football. He graduated from Jones County High School in 1979. Thune played college basketball at Biola University in California; he graduated from Biola in 1983 with a Bachelor of Arts degree in business. He received a Master of Business Administration degree from the University of South Dakota in 1984.
After completing his MBA, Thune became involved in politics. He worked as a legislative aide for U.S. senator James Abdnor from 1985 to 1987. In 1989, Thune moved to Pierre, where he served as executive director of the state Republican Party for two years. Thune was appointed Railroad Director of South Dakota by Governor George S. Mickelson and served from 1991 to 1993. From 1993 to 1996, he was executive director of the South Dakota Municipal League.
U.S. House of Representatives (1997–2003)
Thune began his political career in 1996 by entering the race for South Dakota's lone seat in the U.S. House of Representatives. The Almanac of American Politics said that Thune "entered the 1996 race as very much an underdog." His opponent in the Republican primary was sitting Lieutenant Governor Carole Hillard of Rapid City, who benefited from the support of longtime South Dakota Governor Bill Janklow. A May 1996 poll showed Hillard leading Thune by a margin of 69%–15%. By relying on strong interpersonal skills and the help of his old network of Abdnor friends, Thune won the primary, defeating Hillard 59%–41%. In the general election, Thune defeated Democrat Rick Weiland, a long-serving aide to U.S. Senator Tom Daschle, 58%–37%.
Thune won his subsequent U.S. House races by wide margins. He was reelected in 1998 with 75% of the vote and in 2000 with 73% of the vote.
In 2002, after briefly considering a run for governor, Thune set his sights on the U.S. Senate. He ran against incumbent Democratic U.S. senator Tim Johnson and lost by only 524 votes (0.15%). One study concluded: "While the margin of victory [for Johnson] was a mere 524 votes, getting into that winning position required a number of important factors, including Native American turnout, the ability of Johnson and his allies to more effectively use the ground war to get their message out, Thune's ineffectiveness on the air and lack of experience in winning competitive elections, low voter turnout in key Republican counties, the drought, and finally the presence of Kurt Evans. Evans, a Libertarian candidate who withdrew from the race, endorsed Thune, but remained on the ballot and siphoned away more votes from Thune than Johnson. Evans received only 3,070 votes, but that ended up being six times greater than the margin of victory." Despite the close results, Thune did not contest the election.
In 2004, Thune challenged Tom Daschle, the United States Senate minority leader and leader of the Senate Democratic Caucus. In early 2003, despite speculation, Daschle decided not to run for president the following year. CNN reported that the "announcement surprised even some of his closest aides, one of whom told CNN plans were being made for Daschle to announce his candidacy Saturday in his hometown of Aberdeen, South Dakota."
The 2004 U.S. Senate race in South Dakota was the most expensive Senate race that year, with a total of $30 million spent, and the most expensive race in South Dakota history. It was widely followed in the national media. Thune, along with Senate majority leader Bill Frist, President George W. Bush, and Vice President Dick Cheney, described Daschle as the "chief obstructionist" of Bush's agenda. "Thune was able to criticize 'Daschle for serving incompatible masters' and portray him, as Frist did when he came to South Dakota to campaign for Thune, as a partisan obstructionist and political heir to liberal icon and former Senator George McGovern of South Dakota."
Daschle's critics charged the Democrat with using filibusters to block confirmation of several of Bush's nominees to the federal judiciary and of being out of step with South Dakota voters on other political and social issues: "The GOP had targeted Daschle, the Senate minority leader, claiming he had been the chief obstruction to President Bush on such issues as tax cuts, judicial nominees and the war in Iraq."
On November 2, 2004, Thune defeated Daschle by 4,508 votes, winning 51% of the vote. Daschle's loss was the first ousting of an incumbent floor leader since 1952, when Arizona Senator Ernest McFarland lost to Barry Goldwater. The loss made Daschle "the first Senate party leader in more than five decades to be voted out of office".
South Dakota native Tom Brokaw commented that Thune "ran a very strong campaign" to win the 2004 race. University of South Dakota political scientist Bill Richardson said, "motivated John Thune supporters went to the polls in large numbers, part of a massive South Dakota turnout. Unofficial results show nearly 80 percent of registered voters cast ballots." After Thune defeated Daschle, many Republicans regarded him as a "rising star with unlimited political potential".
Thune was reelected without any opposition in either the primary or general election. Scott Heidepriem, the South Dakota Senate minority leader and a Democratic candidate for Governor of South Dakota, said, "We just concluded that John Thune is an extremely popular senator who is going to win another term in the Senate." The conservative publication Townhall commented that the absence of a Democratic candidate in the election marked "the first time in the state's modern history in which a major party has failed to field a Senate candidate".
Thune faced Democratic nominee Jay Williams, chair of the Yankton County Democratic Party. On November 8, he defeated Williams with 71.8% of the vote.
Thune "drew the wrath of Donald Trump for pushing back on the former president's false claims" that he won the 2020 presidential election. Trump called upon South Dakota governor Kristi Noem to launch a primary challenge to Thune in the 2022 U.S. Senate election in South Dakota; Noem declined. Thune also received negative feedback from Trump supporters for his position on the 2020 election. While Thune seriously considered retiring from the Senate, he announced in January 2022 that he would seek reelection to a fourth term. He was reelected with 69.6% of the vote, defeating Democratic nominee Brian Bengs.