| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | R | 12,712 | 19,486 | 32,804 | |
| 2020 | R | 12,574 | 17,782 | 31,039 | |
| 2016 | R | 10,411 | 14,814 | 27,507 | |
| 2012 | R | 12,551 | 13,052 | 26,072 | |
| 2008 | D | 12,299 | 12,144 | 24,880 | |
| 2004 | R | 10,730 | 12,160 | 23,053 | |
| 2000 | R | 9,521 | 9,621 | 19,653 | |
| 1996 | D | 9,120 | 6,905 | 17,472 | |
| 1992 | D | 8,612 | 7,242 | 19,157 | |
| 1988 | D | 9,627 | 6,424 | 16,131 | |
| 1984 | R | 8,171 | 8,277 | 16,570 | |
| 1980 | R | 6,610 | 7,360 | 15,519 | |
| 1976 | D | 7,653 | 6,099 | 14,108 | |
| 1972 | R | 5,143 | 7,332 | 12,804 | |
| 1968 | R | 4,613 | 5,619 | 11,171 | |
| 1964 | D | 6,639 | 3,679 | 10,351 | |
| 1960 | R | 4,136 | 6,013 | 10,149 | |
| 1956 | R | 3,729 | 5,430 | 9,174 | |
| 1952 | R | 3,042 | 5,911 | 9,017 | |
| 1948 | R | 3,481 | 3,876 | 7,605 | |
| 1944 | R | 3,319 | 4,266 | 7,641 | |
| 1940 | R | 3,856 | 5,016 | 8,923 | |
| 1936 | R | 4,011 | 4,642 | 8,805 | |
| 1932 | R | 3,542 | 3,725 | 7,408 | |
| 1928 | R | 2,239 | 5,294 | 7,591 | |
| 1924 | R | 1,274 | 4,683 | 7,543 | |
| 1920 | R | 2,066 | 5,323 | 7,549 | |
| 1916 | R | 1,910 | 2,182 | 4,179 | |
| 1912 | D | 1,396 | 1,386 | 4,051 | |
| 1908 | R | 1,645 | 2,589 | 4,419 | |
| 1904 | R | 1,191 | 2,938 | 4,438 | |
| 1900 | R | 1,876 | 2,966 | 5,014 | |
| 1896 | R | 2,214 | 2,826 | 5,113 | |
| 1892 | R | 1,475 | 2,414 | 4,315 | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
Warren County sits on the southern edge of the Des Moines metro, and its rapid exurban growth has coincided with a consistent rightward trend, delivering a 20-point Republican margin in 2024 after posting much narrower results in earlier cycles.
The Republican margin in Warren County reached its widest at forty-five points in 1924. The margin in 2024 was twenty-one points, in line with the county's deep historical pattern.
Warren County's loyalty is rooted in its place. Median household income of $94,588, a 93% non-Hispanic-white share, and a population of 54,409 together describe a community whose political habits are deeply settled. The county's voting pattern over the last decade is most similar to that of Moody County and Greene County.
