| Year | Age | State | Party | Office | District | Stage | Pos | Votes | % |
|---|---|---|---|---|---|---|---|---|---|
| 1998 | IA | D | Commissioner of Agriculture | Primary | 1 | 85,757 | 99.7% | ||
| 1998 | IA | D | Commissioner of Agriculture | General | 1 | 451,715 | 50.0% | ||
| 2002 | IA | D | Commissioner of Agriculture | Primary | 1 | 73,988 | 99.4% | ||
| 2002 | IA | D | Commissioner of Agriculture | General | 1 | 490,561 | 50.0% | ||
| 2006 | IA | D | Lt. Governor | General | 1 | 0 | 0.0% | ||
| 2010 | IA | D | Lt. Governor | General | 2 | 0 | 0.0% | ||
| 2016 | IA | D | U.S. Senate Class 3 | Primary | 1 | 46,322 | 47.6% | ||
| 2016 | IA | D | U.S. Senate Class 3 | General | 2 | 549,460 | 35.7% | ||
|
Age: Age as of July 1 of the year pertaining to this election. |