2026 midterm forecast
South Dakota Senate
Brian Bengs (I) vs. Mike Rounds (R)
Forecast published October 30, 2026 · Election Day is November 3, 2026
Foresight forecast
Chance to win
>99%
Mike Rounds
Projected margin
R+16.9
±11 points, 95% range
Undecided
14%
of likely voters
Two-party vote
Key insights
Rounds leads independent Bengs by 17 points in South Dakota
Republicans look secure in this race, where Rounds is seeking reelection against Bengs, an independent. Bengs trails by a wide margin.
Bengs wins 97% of 2024 Harris voters and runs even with college graduates, who favor Rounds by 0.1 points. Rounds builds his lead with men and voters without a degree, carrying them by 39.3 and 36.6 points.
The race
- Independent
- Brian Bengs (I)
- Republican
- Mike Rounds (R)
- Seat held by
- Mike Rounds (R), running
- Note
- No Democrat on the ballot; independent Bengs
Republican Sen. Mike Rounds, a former governor, is seeking a third term. He faces independent Brian Bengs, a retired Air Force officer and the 2022 Democratic nominee, after Democrat Julian Beaudion withdrew. Rounds talks about competition with China on artificial intelligence and wants to require data centers to cover their power costs. Bengs is pushing for campaign finance reform, a Medicare buy-in and a pause in data-center construction.
Campaign summary as of October 29, 2026.
Vote by group
Own vote of likely voters in each group, two-party margin.BengsRounds
Age
Gender
Education
Area
By county
Foresight's margin in each county.
County margins in points. Faded: fewer than 5 respondents. Blank: no respondents.
How this forecast is made: read the method.