South Dakota was won by incumbent President George W. Bush by a 21.5 point margin of victory.

[5][6] South Dakota politics are generally dominated by the Republican Party, and the state has not supported a Democratic presidential candidate since 1964 — even George McGovern, the Democratic nominee in 1972 and himself a South Dakotan, did not carry the state.

As of 2006, Republicans held a ten percent voter registration advantage over Democrats[9] and hold majorities in both the state House of Representatives[10] and Senate.

[11] Despite the state's general Republican and conservative leanings, Democrats have found success in various statewide elections, most notably in those involving South Dakota's congressional representatives in Washington.

[12] Opposition to the Iraq War in this isolationist state[13] did allow Kerry to improve upon Al Gore’s performance in 2000 by two percentage points.

Kerry's gains may also be attributed to Daschle's efforts to get Native American votes during his narrow defeat to John Thune in the concurrent Senate election.

As a result, Kerry won four counties – Corson, Day, Roberts and Ziebach – that Gore had not carried in 2000.