1980Flipped from DemocraticFinal resultsIncumbent defeated
1980 election for South Dakota Legislative District 25
South Dakota State Senate · South Dakota
John D. Manke (R) won with 55.1% of the vote, defeating Marshall J. Truax (D) by 10.2 points, a seat Democrats won last time.
John D. MankeRepublican · winner
55.1%4,390
Marshall J. TruaxDemocrat · incumbent
44.9%3,576
7,966 votes
Source: Harvard Dataverse / Carl KlarnerUpdated Sep 30, 2026, 7:29 AM ET
The seat over time
D − R margin in this seat's races around 1980
Races before and after
Source: Harvard Dataverse / Carl KlarnerUpdated Sep 30, 2026, 7:29 AM ET