The 2002 United States Senate election in South Dakota was held on November 5, 2002. Incumbent Democratic U.S. Senator Tim Johnson narrowly won re-election to a second term by a margin of 524 votes, or 0.15%. This made the election the closest race of the 2002 Senate election cycle.
Thune, who was considered a rising star in his party, ran against Tim Johnson, who narrowly won his first senate election in 1996. Thune launched a television advertising campaign mentioning al Qaeda and Saddam Hussein, contending that both are seeking nuclear weapons and that this country needs a missile defense system, something Johnson voted against 29 times and that Thune supports. The incumbent attacked Thune for politicizing national security.[2] President George W. Bush campaigned for Thune in late October.[3] More than $20 million was spent in the election. Both candidates had raised over $5 million each.[4]
Johnson narrowly prevailed over Thune by a mere 524 votes. Despite the extremely close results, Thune did not contest the results and conceded defeat on the late afternoon of November 9. Johnson's narrow victory may be attributed to his strong support in Oglala Lakota County, and to Thune also underperforming in typically Republican areas. Johnson was sworn in for a second term on January 3, 2003. Thune was elected to South Dakota's other Senate seat in 2004, defeating incumbent minority leader Tom Daschle.