Top story
The Senate state of play: An updated handicapping for mid-October 2026
The continued refusal of Alani Bankhead, the Democratic nominee, to defer to Independent Seth Bodnar makes this race essentially unwinnable for Democrats.
Updated Oct 16, 2026, 1:45 PM ET
Senate · 3 November 2026
South Dakota Senate 2026
- Polymarket
- 91.9%
- Kalshi
- 91.0%
- Spread
- 0.9 pts
- 24h
- –
- 7 days
- −1.8
- Updated
- Oct 16, 2026, 1:45 PM ET
Latest coverage
Live News
Recent coverage for South Dakota Senate.
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Political Pulse: District 34 Senate candidates on growing tech industry
RAPID CITY, S.D. (KOTA) - District 34 consists of Rapid City’s west side and parts of the Black Hills. It includes the famed Dinosaur Park and it borders along the historic Skyline Drive.
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Mike Rounds’ private flights cost taxpayers millions
John Thune, the other senator from South Dakota, missed no votes that year. KOTA reported that Rounds’ private flight expenditures outpaced Thune’s by six to one between October 2021 and September 2022.
American Journal News
Bengs -
South Dakota Midterm Elections: Prediction Market Leaders Today
We’re following the U.S. Senate race between Brian Bengs (I) and Mike Rounds (R) and the gubernatorial race between Dan Ahlers (D) and Larry Rhoden (R), as well as the race for the single U.S. House seat.
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Tracking the 35 Senate seats up for grabs in 2026
The Republicans are hopeful of keeping their majority while the Democrats look to flip enough seats to put them on top.
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Full list of 2026 Senate race candidates
There are 35 Senate seats up for grabs in the 2026 midterm elections.
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It's time for lawmakers to rethink the mobile home
The article, by Emily Hamilton on Spot On South Dakota, discusses the stigma and policy issues surrounding manufactured housing (often called "mobile homes") in South Dakota.
spotonsouthdakota.com
Beaudion -
Ex-Biden appointee faces attorney general in US House race with differences on tariffs, immigration
The article covers a U.S. House race in South Dakota, focusing on Democrat Gronli (former South Dakota director of rural development for USDA under Biden) challenging Republican Attorney General Marty Jackley for the…
News from the StatesBeaudion -
Protecting the state constitution, or protecting voters’ right to change it: Amendment L explained
The article explains Amendment L on South Dakota’s ballot, which would raise the approval threshold for future state constitutional amendments from a simple majority to 60%.
garretsongazette.comBeaudion -
How Sioux Falls-area legislative candidates feel about data centers
The article surveys Sioux Falls-area legislative candidates’ views on data centers, including hyperscale facilities.
sfsimplified.comBeaudion -
Mike Rounds drops Trump references from website
CVS agrees to pay $315 million to settle a Justice Department case alleging it filled medically unnecessary opioid prescriptions 1
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Positions on election hand-counting split candidates in South Dakota’s secretary of state race
The article discusses positions on election hand-counting that split candidates in South Dakota’s secretary of state race, highlighting candidates’ differing views on voting process integrity.
South Dakota SearchlightBeaudion -
South Dakota’s federal-only voter list grows to nearly 6,000, surprising some who are on it - KBHB News
The article reports that in South Dakota, nearly 6,000 voters are restricted to voting only in federal races (U.S. House and U.S. Senate) because they have not produced proof of U.S. citizenship under a new state law.
kbhbradio.comBeaudion -
S.D.'s federal-only voter list grows to nearly 6,000, surprising some on it
The article reports on South Dakota’s growing list of “federal-only” voters, a category created when state law requires proof of U.S. citizenship for voter registration.
watertowncurrent.comBeaudion -
WHAT TO EXPECT ON THE NOV. 3 BALLOT
Marshall County Commission: District 1 (Doug Medhaug, D) unopposed; District 3 (Jason Bender, R) unopposed; District 5 (incumbent Lynda Luttrell not seeking re-election) contested between Republican Tim Dahme and…
marshallcountyjournal.comBeaudion
No story this week names this candidate.
Mike Rounds, last 60 days
How to read this chart
The green line is the TruthIndex™, the chance of this outcome. It combines the prices on both venues and gives more weight to the venue with more money in its order book. The two thinner lines are Polymarket's and Kalshi's own prices, and the grey band between them shows how far apart the two venues are.
The pale bands behind the lines are the rating zones (Toss-up, Lean, Likely and Safe), so you can see when the race moved from one rating to another. Move along the chart, or use the arrow keys, to read the values for each day.
More in MethodologyAll outcomes
| Outcome | TruthIndex™ | Polymarket | Kalshi | Spread | 24h | |
|---|---|---|---|---|---|---|
| Which party wins · Polymarket and Kalshi | ||||||
| RMike Rounds | 91.2% | 91.9% | 91.0% | 0.9 pts | – | |
| IBrian Bengs (Polymarket) | 7.2% Polymarket only |
7.2% | – | – | – | |
| DJulian Beaudion | 0.1% Polymarket only |
0.1% | – | – | – | |
| Which candidate wins · Kalshi | ||||||
| IBrian Bengs (Kalshi) | 8.5% Kalshi only |
– | 8.5% | – | – | |
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Candidates & Background
Brian Bengs
Independent
Brian Bengs, a lawyer, Navy and Air Force veteran and the 2022 Democratic Senate nominee, is running as an independent against Republican Mike Rounds in South Dakota.
Julian Beaudion
Democratic
Julian Beaudion is a former South Dakota state trooper who won the 2026 Democratic Senate nomination unopposed and left the race on August 4, 2026.
Mike Rounds
Republican United States Senator from South Dakota (since 2015)
Mike Rounds, a Republican U.S. senator from South Dakota since 2015 and the state's governor from 2003 to 2011, is seeking a third Senate term against independent Brian Bengs in 2026.
Margin of victory
Each venue's margin market, shown on its own: the two venues set their ranges differently.
Kalshi10.4K contracts
South Dakota Senate margin of victory
| Rounds, 3+ pts | 87.1% | |
| Rounds, 5+ pts | 81.5% | |
| Rounds, 7+ pts | 73.5% | |
| Rounds, 9+ pts | 64.0% | |
| Rounds, 11+ pts | 62.5% | |
| Rounds, 13+ pts | 45.5% | |
| Rounds, 15+ pts | 37.0% | |
| Rounds, 17+ pts | 29.0% | |
| Rounds, 19+ pts | 24.5% | |
| Rounds, 21+ pts | 14.0% | |
| Rounds, 23+ pts | – | |
| Rounds, 25+ pts | – | |
| Rounds, 27+ pts | 5.3% | |
| Rounds, 29+ pts | 4.5% | |
| Rounds, 31+ pts | 4.1% | |
| Rounds, 33+ pts | 2.5% | |
| Rounds, 35+ pts | 4.7% implied |
Polymarket$21.1K traded
South Dakota Senate Election Margin of Victory
| Independent Wins | 6.6% | |
| Republican 0-10% | 28.3% | |
| Republican 10-15% | 34.0% | |
| Republican 15-20% | 17.0% | |
| Republican 20-25% | – | |
| Republican 25-30% | 3.4% | |
| Republican 30-35% | 2.9% | |
| Republican 35-40% | 0.9% | |
| Republican 40-45% | 0.5% | |
| Republican 45%+ | 0.5% |
Each venue's market
Polymarket$62.0K traded
Prices which party wins.
Mike Rounds: Counted · bid 91.6% / ask 92.1% · $5.1K within 5 pts
This market will resolve according to the winner of the 2026 midterm South Dakota U.S. Senate election, inclusive of any run-offs. A candidate shall be considered to represent a party in the event that he or she is the nominee of the party in question. Candidates other than the Democratic or Republican nominee (e.g., Greens, Libertarian, independent) may be added at a later date. Candidates who run as independents will not be encompassed by the “Democrat” or “Republican” options regardless of any affiliation they may have with the party. The candidates may be named in the contract for the convenience of traders. In the event that any named candidate is replaced as the nominee of their respective party prior to election day, the name in the contract will be updated and the market will resolve based on the replacement nominee of the party. The resolution source for this market is the Associated Press, Fox News, and NBC. This market will resolve once all three sources call the race for the same candidate. If all three sources haven’t called the race in this state for the same candidate, this market will resolve based on the official certification.
Full rules on PolymarketKalshi311.2K contracts traded
Prices which party wins.
Mike Rounds: Counted · bid 90.9% / ask 91.0% · $17.6K within 5 pts
Contract shown: Mike Rounds
If a representative of the Republican party is sworn in as a Senator of South Dakota for the term beginning in 2027, then the market resolves to Yes.
This market is eligible for accelerated determination after a consensus of media organizations project the winner. See full rules for details.
Also in South Dakota
- South Dakota GovernorR98%
- SD-AL HouseR95%