Closest U.S. Senate elections in Iowa
The closest U.S. Senate election in Iowa history was in 1924, a margin of 0.08 points. Smith W. Brookhart beat Daniel F. Steck, 447,706 to 446,951. Next closest are 1938 (0.33 points) and 1968 (0.56 points).
Every state is ranked together on Closest U.S. Senate elections in history. For every Senate race Iowa has held, special elections included, see the Iowa U.S. Senate hub.
What is the closest Senate race in Iowa history?
The Iowa Senate election decided by the narrowest margin was in 1924, 0.08 points. Smith W. Brookhart beat Daniel F. Steck, 447,706 to 446,951. The next closest were 1938 (0.33 points) and 1968 (0.56 points).
How is the margin measured?
As the gap in vote share between the first and second-place finishers, from the certified general-election count. It is not adjusted for recounts, runoffs or later court rulings; the figure is the result as certified.
Does this include special elections?
No. These are the regular general elections for Iowa’s two Senate seats. Special elections to fill a vacancy appear on the Iowa Senate hub, which lists every race including specials, and in a few states one of those is closer than anything here.
Why does the list start in 1914?
Because senators were chosen by state legislatures before the Seventeenth Amendment. 1914 is the first cycle of the popular-vote era for the Senate, so it is the first Iowa election with a popular margin to measure.
| # | Election | Result | Votes | Margin |
|---|---|---|---|---|
| 1 | 1924 | Smith W. Brookhart R def. Daniel F. Steck D | 447,706 – 446,951 | 0.08 points |
| 2 | 1938 | Guy M. Gilette D def. Lester J. Dickinson R | 413,788 – 410,983 | 0.33 points |
| 3 | 1968 | Harold E. Hughes D def. David M. Stanley R | 574,884 – 568,469 | 0.56 points |
| 4 | 1944 | Bourke B. Hickenlooper R def. Guy M. Gilette D | 523,963 – 494,229 | 2.9 points |
| 5 | 1978 | Roger W. Jepsen R def. Dick Clark D | 421,598 – 395,066 | 3.2 points |
| 6 | 1936 | Clyde L. Herring D def. Lester J. Dickinson R | 539,555 – 503,635 | 3.4 points |
| 7 | 1960 | Jack Miller R def. Herschel C. Loveless D | 642,463 – 595,119 | 3.8 points |
| 8 | 1954 | Thomas E. Martin R def. Guy M. Gilette D | 442,409 – 402,712 | 4.7 points |
| 9 | 1974 | John Culver D def. David M. Stanley R | 462,947 – 420,546 | 4.8 points |
| 10 | 1996 | Tom Harkin D def. Jim Lightfoot R | 634,166 – 571,807 | 5.1 points |
| 11 | 2020 | Joni Ernst R def. Theresa Greenfield D | 864,997 – 754,859 | 6.5 points |
| 12 | 1962 | Bourke B. Hickenlooper R def. E. B. Smith D | 431,364 – 376,602 | 6.8 points |
| 13 | 1956 | Bourke B. Hickenlooper R def. R. M. Evans D | 635,499 – 543,156 | 7.8 points |
| 14 | 1980 | Charles E. Grassley R def. John Culver D | 683,014 – 581,545 | 8.0 points |
| 15 | 2014 | Joni Ernst R def. Bruce Braley D | 588,575 – 494,370 | 8.3 points |
| 16 | 1914 | Albert B. Cummins R def. Maurice Connolly D | 205,832 – 167,251 | 9.0 points |
| 17 | 1990 | Tom Harkin D def. Thomas J. Tauke R | 535,975 – 446,869 | 9.0 points |
| 18 | 1950 | Bourke B. Hickenlooper R def. Albert J. Loveland D | 470,613 – 383,766 | 10.1 points |
| 19 | 2002 | Tom Harkin D def. Greg Ganske R | 554,278 – 447,892 | 10.4 points |
| 20 | 1972 | Dick Clark D def. Jack Miller R | 662,637 – 530,525 | 11.0 points |
| 21 | 1984 | Tom Harkin D def. Roger W. Jepsen R | 716,883 – 564,381 | 11.8 points |
| 22 | 2022 | Charles E. Grassley R def. Michael Franken D | 681,501 – 533,330 | 12.0 points |
| 23 | 1926 | Smith W. Brookhart R def. Claude R. Porter D | 323,409 – 247,869 | 13.2 points |
| 24 | 1930 | Lester J. Dickinson R def. Daniel F. Steck D | 307,613 – 235,186 | 13.3 points |
| 25 | 1932 | Lewis Murphy D def. Henry Field R | 538,422 – 399,929 | 13.9 points |