SIOUX FALLS, S.D. — Republican U.S. Sen. Mike Rounds holds an eight-point lead over independent challenger Brian Bengs in a new statewide poll, although the survey reveals significant differences among younger voters, older residents and those who have already cast ballots.
The Emerson College Polling/KELOLAND survey, released Oct. 22, found Rounds receiving 50% support among likely voters compared with 42% for Bengs, with 8% undecided.
When undecided voters were asked which candidate they leaned toward, Rounds’ support increased to 54%, while Bengs reached 46%.
The poll surveyed 803 likely South Dakota voters Oct. 19-21 and carried a credibility interval of plus or minus 3.5 percentage points.
The findings come as Rounds seeks a third six-year term in a state where Republicans have maintained a substantial advantage in federal elections. Bengs, a former Democratic Senate candidate, is running as an independent and has emphasized campaign finance reform and reducing the influence of political parties in Washington.
Other recent surveys have shown larger leads for Rounds.
A Mason-Dixon poll conducted Oct. 12-14 for South Dakota News Watch and the University of South Dakota’s Chiesman Center for Democracy found Rounds ahead 56% to 37%.
A separate Quantus Insights survey conducted Oct. 17-19 placed Rounds at approximately 57% and Bengs at 37%.
The differences among the surveys illustrate uncertainty over the size of Rounds’ advantage, although each of those October polls showed the incumbent ahead.
The Emerson survey identified a notable generational divide. Among voters younger than 40, Bengs led Rounds 48% to 41%. Among voters older than 50, Rounds held a 54% to 38% advantage.
Gender also played a role in the results. Rounds received support from 56% of male voters compared with 39% for Bengs. Women were evenly divided, with each candidate receiving 44%.
One of the more unusual findings involved early voting. Among respondents who had already cast ballots, Bengs led 55% to 45%. However, voters who had not yet voted supported Rounds 50% to 40%.
The early-voter findings were based on a smaller sample of 94 respondents, compared with 709 voters who had not yet cast ballots, making that portion of the survey less precise.
The results suggest that the candidates are drawing support from different segments of the electorate, although the survey does not establish how those patterns will translate into the final vote.
Bengs, a military veteran and former law professor, previously challenged Republican Sen. John Thune as a Democrat in 2022.
This year, he is running without a major-party affiliation, arguing that Washington’s political system is overly influenced by party leadership and large campaign donors.
Bengs has made campaign finance reform a central issue, advocating changes intended to reduce the influence of money in federal elections and increase accountability among elected officials.
Rounds, a former South Dakota governor first elected to the Senate in 2014, has emphasized his experience in Congress, national security and support for the state’s agricultural and business interests.
He serves on the Senate Armed Services Committee and has focused on defense policy, agriculture and economic development during his tenure.
The contest also comes amid shifting attitudes toward President Donald Trump in South Dakota. The Emerson poll found Trump’s job approval rating at 44%, with 52% disapproving.
That represented a nine-point decline in approval since May, while disapproval increased 10 points over the same period.
South Dakota has consistently supported Republican presidential candidates, with Trump carrying approximately 63% of the statewide vote in 2024.
The state has not elected a Democrat to the U.S. Senate since Tim Johnson won his final term in 2008.
The Mason-Dixon survey found 62% of independents supporting Bengs, compared with 30% backing Rounds. However, the same survey found strong Republican support for the incumbent, with 85% of GOP voters backing Rounds.
The Emerson poll also identified ticket splitting in the state’s gubernatorial election. Approximately 12% of voters supporting Republican Gov. Larry Rhoden said they intended to vote for Bengs in the Senate race.
With the Nov. 3 general election approaching, the latest polling provides a snapshot of a contest in which Rounds retains an advantage while Bengs draws support from younger voters, independents and some Republicans willing to split their ballots.