The positions of majority leader and minority leader are held by two United States senators and people of the party leadership of the United States Senate. They serve as a chief spokespersons for their respective political parties holding the majority and the minority in the United States Senate. They are each elected as majority leader and minority leader by the senators of their party caucuses: the Senate Democratic Caucus and the Senate Republican Conference.

John Randolph Thune is an American politician serving as the senior United States senator from South Dakota, a seat he has held since 2005. Thune is in his fourth Senate term and is the Senate minority whip, a post he has held since 2021. A member of the Republican Party, Thune served three terms as the U.S. representative for South Dakota's at-large congressional district from 1997 to 2003.