| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | R | 4,447 | 14,407 | 19,230 | |
| 2020 | R | 4,493 | 14,304 | 19,214 | |
| 2016 | R | 3,945 | 12,412 | 17,419 | |
| 2012 | R | 5,596 | 10,524 | 16,481 | |
| 2008 | R | 7,657 | 9,357 | 17,314 | |
| 2004 | R | 6,797 | 10,219 | 17,131 | |
| 2000 | R | 6,436 | 8,588 | 15,427 | |
| 1996 | D | 6,104 | 6,065 | 13,844 | |
| 1992 | D | 6,686 | 5,771 | 15,822 | |
| 1988 | R | 5,935 | 7,681 | 13,680 | |
| 1984 | R | 4,628 | 9,233 | 13,899 | |
| 1980 | R | 4,470 | 8,500 | 13,593 | |
| 1976 | R | 6,275 | 7,245 | 13,671 | |
| 1972 | R | 4,756 | 7,931 | 12,712 | |
| 1968 | R | 4,453 | 6,561 | 12,199 | |
| 1964 | D | 7,339 | 4,692 | 12,031 | |
| 1960 | D | 6,188 | 5,709 | 11,903 | |
| 1956 | R | 4,242 | 7,378 | 11,627 | |
| 1952 | R | 4,853 | 6,760 | 11,620 | |
| 1948 | R | 4,773 | 5,128 | 9,963 | |
| 1944 | R | 3,944 | 6,753 | 10,750 | |
| 1940 | R | 4,558 | 7,582 | 12,230 | |
| 1936 | D | 5,355 | 3,653 | 11,145 | |
| 1932 | D | 7,736 | 2,548 | 10,466 | |
| 1928 | D | 6,774 | 3,031 | 9,852 | |
| 1924 | R | 1,693 | 2,358 | 7,942 | |
| 1920 | R | 1,661 | 4,564 | 7,164 | |
| 1916 | D | 4,201 | 3,423 | 8,026 | |
| 1912 | D | 2,674 | 973 | 4,750 | |
| 1908 | D | 3,016 | 2,104 | 5,380 | |
| 1904 | D | 2,153 | 1,848 | 4,296 | |
| 1900 | D | 2,637 | 1,964 | 4,721 | |
| 1896 | D | 2,572 | 1,863 | 4,462 | |
| 1892 | D | 2,393 | 1,361 | 3,925 | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
Clinton County, anchored by small agricultural communities southeast of St. Louis, has shifted decisively rightward over the past two decades, posting a 51.8-point Republican margin in 2024 despite sitting within a state that votes reliably Democratic at the statewide level.
The Republican margin in Clinton County reached its widest at fifty-two points in 2024. The margin in 2024 was fifty-two points, in line with the county's deep historical pattern.
Clinton County's loyalty is rooted in its place. Median household income of $86,588, a 91% non-Hispanic-white share, and a population of 36,954 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 Franklin County and Caldwell County.