South Dakota 2026 SENATE FORECAST

2026 South Dakota Senate Forecast:

The Pollsmax 2026 South Dakota Senate forecast currently gives Republican Mike Rounds a 99.7% chance of defeating Democrat Julian Beaudion. Pollsmax projects Rounds to receive 60.8% of the vote compared with 39.3% for Beaudion, a projected Republican margin of 21.5 percentage points. The model currently rates the race as Solid Republican. The forecast is updated using 100,000 simulations incorporating polling and race fundamentals. See the Pollsmax forecast methodology.

The 2026 South Dakota Senate election features Democrat Julian Beaudion and Republican Mike Rounds. Incumbent senator Mike Rounds is seeking reelection to a third term, having served in the US Senate since 2015. In 2024, Donald Trump won South Dakota by 29.2%, and Republicans are expected to easily retain the state's Senate seat in 2026. The race will test whether the incumbent party can hold its existing Senate coalition as national conditions shift during the midterm cycle.