The 1998 United States Senate election in Iowa was held November 3, 1998. Incumbent Republican United States Senator Chuck Grassley sought re-election to a fourth term in the United States Senate, running against former State Representative David Osterberg, who won the Democratic nomination unopposed. Grassley had not faced a competitive election since 1980; this year proved no different, and Grassley defeated Osterberg in a landslide.

Democratic primary

Candidates

Results

Democratic primary results[1]
Party Candidate Votes %
Democratic David Osterberg 86,064 99.45%
Democratic Write-ins 476 0.55%
Total votes 86,540 100.00%

Republican primary

Candidates

Results

Republican primary results[1]
Party Candidate Votes %
Republican Chuck Grassley (Incumbent) 149,943 99.72%
Republican Write-ins 419 0.28%
Total votes 150,362 100.00%

General election

Debate

1998 Iowa United States Senate election debate
No. Date Host Moderator Link Republican Democratic
Key:
 P  Participant   A  Absent   N  Not invited   I  Invited  W  Withdrawn
Chuck Grassley David Osterberg
1 Oct. 19, 1998 Iowa Public Television Dean Borg C-SPAN P P

Polling

Poll source Date(s)
administered		 Sample
size[a]		 Margin
of error		 Chuck
Grassley (R)		 David
Osterberg (D)		 Undecided
Mason Dixon[2] October 25–27, 1998 803 (LV) ± 3.5% 68% 24% 8%
Mason Dixon[2] October 11–13, 1998 809 (LV) ± 3.5% 67% 22% 11%
Mason Dixon[2] September 12–14, 1998 804 (LV) ± 3.5% 69% 19% 12%
Mason Dixon[2] July 18–21, 1998 834 (LV) ± 3.5% 68% 17% 15%
Selzer & Company[2] June 20–24, 1998 581 (LV) ± 4.0% 72% 18% 10%

Results

United States Senate election in Iowa, 1998[3]
Party Candidate Votes % ±%
Republican Chuck Grassley (Incumbent) 648,480 68.41% −1.20%
Democratic David Osterberg 289,049 30.49% +3.29%
Natural Law Susan Marcus 7,561 0.80% −0.47%
Socialist Workers Margaret Trowe 2,542 0.27% +0.16%
Write-ins 275 0.03%
Majority 359,431 37.92% −4.50%
Turnout 947,907
Republican hold Swing

See also

Notes

  1. ↑ Key:
    A – all adults
    RV – registered voters
    LV – likely voters
    V – unclear

References

  1. 1 2 "Results" (PDF). sos.iowa.gov. 1998. Retrieved October 15, 2019.
  2. 1 2 3 4 5 "CNN AllPolitics Election '98 - Iowa 1998 Polls". CNN. Retrieved June 25, 2025.{{cite web}}: CS1 maint: deprecated archival service (link)
  3. ↑ "Election info" (PDF). clerk.house.gov. 1998. Retrieved October 15, 2019.
source: https://en.wikipedia.org/wiki/1998_United_States_Senate_election_in_Iowa