2004 United States Senate election in Iowa
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 County results Grassley: 50-60% 60-70% 70-80% 80-90% >90% | |||||||||||||||||
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The 2004 United States Senate election in Iowa was held on November 2, 2004. Incumbent Republican United States Senator Chuck Grassley ran for re-election to a fifth term in the United States Senate. Grassley and former State Senator Arthur A. Small won the Republican and Democratic primaries, respectively, unopposed, and faced each other in the general election. Though this election coincided with the highly competitive presidential election, Grassley was not considered vulnerable and defeated Small in a landslide.
As of 2024, this is the last time a Republican Senate candidate won Johnson County. As of 2024, this is also the last time that the winning United States Senate candidate carried all counties in Iowa for this seat.
Democratic primary
Candidates
- Arthur A. Small, attorney, lobbyist, and former Iowa State Senator
Results
| Party | Candidate | Votes | % | |
|---|---|---|---|---|
| Democratic | Arthur A. Small | 52,318 | 99.25% | |
| Democratic | Write-ins | 398 | 0.75% | |
| Total votes | 52,716 | 100.00% | ||
Republican primary
Candidates
- Chuck Grassley, incumbent United States Senator
Results
| Party | Candidate | Votes | % | |
|---|---|---|---|---|
| Republican | Chuck Grassley (Incumbent) | 78,819 | 99.72% | |
| Republican | Write-ins | 218 | 0.28% | |
| Total votes | 79,037 | 100.00% | ||
General election
Predictions
| Source | Ranking | As of |
|---|---|---|
| Sabato's Crystal Ball[2] | Safe R | November 1, 2004 |
Results
| Party | Candidate | Votes | % | ±% | |
|---|---|---|---|---|---|
| Republican | Chuck Grassley (Incumbent) | 1,038,175 | 70.18% | +1.77% | |
| Democratic | Arthur A. Small | 412,365 | 27.88% | -2.62% | |
| Libertarian | Christy Ann Welty | 15,218 | 1.03% | ||
| Green | Daryl A. Northrop | 11,121 | 0.75% | ||
| Socialist Workers | Edwin Fruit | 1,874 | 0.13% | -0.14% | |
| Write-ins | 475 | 0.03% | |||
| Majority | 625,810 | 42.31% | +4.39% | ||
| Turnout | 1,479,228 | ||||
| Republican hold | Swing | ||||
