The 2008 United States Senate election in Idaho was held on November 4, 2008. The primary elections were held on May 27. Incumbent Senator Larry Craig decided to retire instead of seeking a fourth term. Fellow Republican Jim Risch won the open seat.

Background

Incumbent Larry Craig announced his intent to resign following an incident where he allegedly solicited another man for gay sex in a public restroom. Craig later decided not to resign but did announce that he would not seek re-election. The filing deadline for the election was March 21, 2008. A total of 13 candidates filed for the seat. Republican and Democratic candidates ran for their respective nominations in the May 27 primary. Lieutenant Governor Jim Risch defeated a crowded field for the Republican nomination, while former Congressman Larry LaRocco won the Democratic nomination in similar fashion. Conservative independents Rex Rammell and Pro-Life (formerly Marvin Richardson) also qualified for the general election ballot. Former Caldwell city council member Kent Marmon secured the Libertarian nomination. In the general election, Risch defeated LaRocco and the other candidates to keep the seat in Republican hands.

Republican primary

Candidates

Results

Democratic primary

Candidates

Results

General election

Candidates

Predictions

Polling

Results

Counties that flipped from Republican to Democratic