1940 United States Senate election in Washington
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 County results Wallgren: 50–60% 60–70% Chadwick: 50–60% 60–70% 70–80% | |||||||||||||||||
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The 1940 United States Senate election in Washington was held on November 5, 1940. Incumbent Democrat Lewis Schwellenbach did not run for a second term in office. He was succeeded by Democratic U.S. Representative Monrad C. Wallgren, who defeated Republican Stephen Foster Chadwick for the open seat.
Blanket primary
Candidates
Democratic
- Frank T. Bell, former Commissioner of Fish and Fisheries, former Treasurer of Grant County, and businessman
- Harry C. Huse
- Donald B. Miller, State Representative, and businessman
- Roy B. Misener, King County Assessor
- Robert Lee Smith
- Monrad Wallgren, U.S. Representative from Everett
Republican
- Stephen Fowler Chadwick, son of Stephen J. Chadwick, and candidate for Representative from Washington in 1926
- Ewing D. Colvin, former Prosecutor of King County, and Washington State Bar Association official
- Howard E. Foster
- Eric Johnston, businessman, and former Marine
- Robert Prior
Results
| Party | Candidate | Votes | % | |
|---|---|---|---|---|
| Republican | Stephen Foster Chadwick | 137,320 | 27.45% | |
| Democratic | Monrad Wallgren | 96,747 | 19.34% | |
| Democratic | Frank T. Bell | 51,510 | 10.30% | |
| Democratic | Harry C. Huse | 50,930 | 10.18% | |
| Republican | Eric Johnston | 42,542 | 8.51% | |
| Democratic | Roy B. Misener | 41,259 | 8.25% | |
| Republican | Ewing D. Colvin | 27,903 | 5.58% | |
| Republican | Robert Prior | 19,194 | 3.84% | |
| Democratic | Robert Lee Smith | 13,918 | 2.78% | |
| Democratic | Donald B. Miller | 11,904 | 2.38% | |
| Republican | Howard E. Foster | 6,954 | 1.39% | |
| Total votes | 500,181 | 100.00% | ||
General election
Results
| Party | Candidate | Votes | % | ±% | |
|---|---|---|---|---|---|
| Democratic | Monrad Wallgren | 404,718 | 54.16% |  6.77 | |
| Republican | Stephen Fowler Chadwick | 342,589 | 45.84% |  11.82 | |
| Total votes | 747,307 | 100.00% | |||
| Democratic hold | Swing | ||||
