| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | R | 3,032 | 9,991 | 13,153 | |
| 2020 | R | 3,202 | 9,915 | 13,376 | |
| 2016 | R | 2,994 | 9,419 | 12,787 | |
| 2012 | R | 4,031 | 7,923 | 12,158 | |
| 2008 | R | 4,703 | 7,705 | 12,553 | |
| 2004 | R | 4,568 | 7,815 | 12,453 | |
| 2000 | R | 4,993 | 6,550 | 11,712 | |
| 1996 | D | 4,924 | 4,653 | 10,721 | |
| 1992 | D | 5,156 | 4,762 | 11,783 | |
| 1988 | D | 5,617 | 5,034 | 10,674 | |
| 1984 | R | 4,666 | 6,831 | 11,497 | |
| 1980 | R | 5,890 | 6,036 | 12,186 | |
| 1976 | D | 6,124 | 5,501 | 11,663 | |
| 1972 | R | 4,171 | 7,197 | 11,368 | |
| 1968 | D | 5,416 | 4,732 | 11,369 | |
| 1964 | D | 8,314 | 3,605 | 11,919 | |
| 1960 | D | 6,758 | 6,431 | 13,189 | |
| 1956 | D | 6,874 | 5,657 | 12,531 | |
| 1952 | D | 8,457 | 6,162 | 14,637 | |
| 1948 | D | 9,122 | 3,802 | 12,944 | |
| 1944 | D | 8,575 | 4,560 | 13,149 | |
| 1940 | D | 9,723 | 5,892 | 15,660 | |
| 1936 | D | 11,068 | 4,628 | 15,747 | |
| 1932 | D | 10,293 | 4,123 | 14,519 | |
| 1928 | R | 5,679 | 7,664 | 13,367 | |
| 1924 | D | 5,739 | 5,408 | 12,297 | |
| 1920 | D | 6,719 | 4,660 | 11,545 | |
| 1916 | D | 4,534 | 2,759 | 7,401 | |
| 1912 | D | 3,471 | 1,693 | 5,909 | |
| 1908 | D | 3,982 | 2,554 | 6,772 | |
| 1904 | D | 3,127 | 2,433 | 5,762 | |
| 1900 | D | 3,927 | 2,490 | 6,526 | |
| 1896 | D | 4,008 | 2,699 | 6,759 | |
| 1892 | D | 3,634 | 2,154 | 5,907 | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
Marion County anchors Missouri's northeastern corner along the Mississippi, where a shrinking small-city population and deep agricultural roots have pushed presidential margins from competitive to lopsided since the early 2000s.
The unraveling was not abrupt. The Democratic margin in Marion County peaked at forty-two points in 1932; it narrowed steadily over the late twentieth century. The 2000 election delivered the county to the Republican party for the first time in many years, by a margin of thirteen points. By 2024, the margin had widened further.
The economic and demographic context is severe. Marion County's median household income of $62,903 is among the lowest of any county in the United States; 14% of residents live below the federal poverty line. The county's voting pattern over the last decade is most similar to that of Shelby County and Gentry County.