| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | D | 10,480 | 8,699 | 20,027 | |
| 2020 | D | 11,184 | 9,067 | 21,126 | |
| 2016 | D | 8,146 | 7,403 | 18,028 | |
| 2012 | R | 8,037 | 8,507 | 17,270 | |
| 2008 | D | 9,070 | 8,104 | 17,589 | |
| 2004 | R | 8,287 | 9,397 | 18,012 | |
| 2000 | R | 6,509 | 9,003 | 16,237 | |
| 1996 | D | 7,262 | 6,734 | 15,895 | |
| 1992 | D | 7,637 | 6,428 | 17,478 | |
| 1988 | R | 7,403 | 7,680 | 15,333 | |
| 1984 | R | 6,621 | 10,021 | 16,849 | |
| 1980 | R | 5,726 | 8,636 | 17,024 | |
| 1976 | R | 6,197 | 8,168 | 15,068 | |
| 1972 | R | 6,248 | 9,548 | 16,266 | |
| 1968 | R | 5,218 | 7,810 | 13,789 | |
| 1964 | R | 6,760 | 6,765 | 13,538 | |
| 1960 | R | 5,458 | 8,069 | 13,544 | |
| 1956 | R | 4,854 | 8,572 | 13,434 | |
| 1952 | R | 4,611 | 8,905 | 13,560 | |
| 1948 | R | 6,015 | 6,411 | 12,740 | |
| 1944 | R | 5,449 | 6,000 | 11,490 | |
| 1940 | R | 6,351 | 6,356 | 12,799 | |
| 1936 | D | 7,753 | 3,955 | 11,973 | |
| 1932 | D | 5,945 | 4,727 | 11,011 | |
| 1928 | R | 2,969 | 7,065 | 10,101 | |
| 1924 | R | 1,745 | 4,960 | 9,516 | |
| 1920 | R | 2,806 | 6,344 | 9,809 | |
| 1916 | D | 5,888 | 4,933 | 11,251 | |
| 1912 | D | 3,621 | 1,989 | 9,943 | |
| 1908 | R | 2,386 | 3,376 | 6,418 | |
| 1904 | R | 1,519 | 4,090 | 6,152 | |
| 1900 | D | 2,826 | 2,366 | 5,565 | |
| 1896 | D | 3,690 | 1,592 | 5,367 | |
| 1892 | R | 2,061 | 2,131 | 5,709 | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
Whitman County's lean toward Democratic presidential candidates is driven largely by Washington State University's student and faculty population in Pullman, making it an outlier in an otherwise Republican-leaning agricultural region.
The Democratic margin in Whitman County has rarely exceeded thirty-nine points in modern history; the Republican margin has rarely exceeded forty-two points. 2024 delivered the county to the Democratic candidate by nine points.
Whitman County's demographics resemble the country more than they resemble most counties. A 76% non-Hispanic-white share, a 23% poverty rate, and a median household income of $55,406 — all within the broad national range. The county's voting pattern over the last decade is most similar to that of Clallam County and Hays County.
