South Dakota Senate Voting Record: What Roll-Call Votes Reveal About 2026 Candidates

The Public Record Landscape for South Dakota's 2026 Senate Race

In the last three cycles, Senate campaigns in states with limited media markets — such as South Dakota — relied heavily on legislative voting records to define candidates before paid advertising began. Voters in these states often know their senators personally, but they may not track every roll-call vote. Public records from the state legislature and Congress become the raw material for both positive and negative framing.

For the 2026 South Dakota Senate race, the field includes candidates with varying public service histories. Some have served in the U.S. House or the South Dakota Legislature, while others have no elected office experience. A systematic examination of their voting records — where they exist — allows campaigns to anticipate attack lines and contrast messages before they appear in ads or debates.

OppIntell's research team has compiled available roll-call data from public sources, including the U.S. Congress and the South Dakota Legislative Research Council. This article walks through what the records show, where gaps remain, and how competitive research teams would use this material in a race context.

Candidate Biographies and Legislative Backgrounds

The 2026 South Dakota Senate race features candidates from both major parties. On the Republican side, incumbent Senator John Thune is seeking reelection. Thune has served in the Senate since 2005 and previously served in the U.S. House from 1997 to 2003. His voting record spans nearly three decades in federal office, covering major legislation on taxes, health care, agriculture, and judicial confirmations.

Democratic candidates include Brian Bengs, a U.S. Navy veteran and attorney who ran for the same seat in 2020 and 2022. Bengs has no legislative voting record, as he has never held elected office. His campaign materials emphasize military service and legal career, but researchers would note the absence of a public voting history as a factor in how he can be defined by opponents.

Other candidates may emerge before the filing deadline. In recent cycles, South Dakota has seen third-party and independent candidates, though none have won. For this analysis, the focus is on candidates with a verifiable legislative voting record from public sources.

Race Context: South Dakota's Senate Dynamics

In the last three cycles, South Dakota Senate races have been consistently Republican-leaning. The state has not elected a Democrat to the Senate since Tom Daschle in 1986. The 2020 race saw Thune win by over 30 points against a Democratic challenger with minimal name recognition. The 2022 race was similarly lopsided.

For 2026, Thune enters as the heavy favorite. National analysts rate the race as Safe Republican. However, primary challenges from the right have become more common in the Trump era. In 2022, Thune faced a primary challenger but won easily. Any serious primary opponent would need to contrast their voting record — if they have one — against Thune's lengthy Senate record, particularly on issues like trade, spending, and executive power.

Democrats face an uphill climb. Without a strong legislative record to run on, their candidates typically focus on local issues and personal biography. Bengs, for example, highlights his military service and small-town roots. But in a state where partisan identification heavily predicts voting behavior, the absence of a voting record may leave him vulnerable to being painted as too liberal by association with national Democratic positions.

What the Voting Records Show: Thune's Senate Roll-Call History

John Thune's Senate voting record is extensive and well-documented. He has missed fewer than 2% of votes during his tenure, according to public data from GovTrack. His voting record aligns closely with the Republican leadership on most issues, though he has occasionally broken with the party on matters important to South Dakota, such as farm policy and ethanol mandates.

Key votes that researchers would examine include the Tax Cuts and Jobs Act of 2017, which Thune supported; the Affordable Care Act repeal efforts; the confirmation of Supreme Court justices; and COVID-19 relief packages. On trade, Thune has generally supported free trade agreements but voted for tariffs on China under President Trump. On agriculture, he has backed farm bills with strong subsidy and crop insurance provisions.

For a primary challenger, these votes provide ammunition. A more conservative opponent could argue Thune was insufficiently supportive of Trump on trade or immigration. A general election opponent would have a harder time painting Thune as extreme, given his incumbency and the state's Republican lean. Instead, a Democrat might try to tie Thune to unpopular national Republican positions on Medicare and Social Security.

What the Voting Records Show: Bengs and Candidates Without Legislative History

Brian Bengs has no legislative voting record. In 2020 and 2022, he ran on a platform of bipartisanship and pragmatic problem-solving. Without roll-call votes to analyze, researchers would look to other public records: campaign statements, interviews, social media posts, and past endorsements. These can serve as a proxy for a voting record, though they carry less weight in competitive research.

For opposition researchers, a candidate without a voting record is both a challenge and an opportunity. It is harder to pin down specific positions, but it also allows opponents to fill the void with assumptions. In the last three cycles, Democratic candidates in deep-red states without legislative records have been defined by their party's national brand rather than their own actions. Bengs would likely face the same dynamic.

Researchers would also examine Bengs's past campaign platforms. In 2022, he supported protecting Social Security and Medicare, expanding rural health care, and opposing cuts to farm subsidies. These positions mirror mainstream Democratic talking points but are not backed by a voting record. Opponents could argue that his stated positions are vague or that he would follow party leadership once in office.

Financial Posture and Campaign Resources

In the last three cycles, South Dakota Senate races have been relatively low-spending compared to competitive states. Thune has consistently raised substantial sums, reporting over $10 million in his 2022 reelection campaign. For 2026, he had over $2 million cash on hand as of the most recent FEC filing.

Bengs has not filed a 2026 campaign finance report yet. In 2022, he raised around $500,000, a fraction of Thune's war chest. Without a strong fundraising network, his ability to communicate his message through paid media is limited. This makes earned media and debate performance critical, yet South Dakota's small media market means ads can be relatively inexpensive.

For campaigns, understanding the financial posture is essential for predicting opposition research strategies. A well-funded incumbent can afford to define a challenger early through ads highlighting their lack of a voting record or tying them to national party figures. A cash-strapped challenger must rely on free media and may try to provoke gaffes or controversies.

Competitive Research Framing: How Opponents Would Use These Records

In the last three cycles, opposition research in Senate races has moved beyond simple vote tallying to narrative construction. A voting record is not just a list of yeses and nos; it is a story about a candidate's priorities, alliances, and reliability. For Thune, the story is one of a mainstream Republican who sometimes breaks with the party on local issues. For Bengs, the story is one of a blank slate that opponents can write on.

A primary challenger to Thune might highlight votes that angered the conservative base: support for omnibus spending bills, votes to certify the 2020 election, or any deviation from Trump-era orthodoxy. Researchers would pull specific roll-call votes and pair them with quotes from conservative media to create a narrative of insufficient loyalty.

A Democratic opponent would likely avoid attacking Thune's voting record directly, given its alignment with South Dakota's preferences. Instead, they might try to nationalize the race by linking Thune to unpopular Republican policies on abortion or health care. Without a voting record of their own, the Democrat would need to rely on biography and local issues, making personal attacks from the other side more damaging.

Source-Posture Awareness: What Public Records Can and Cannot Say

Public voting records are a powerful tool, but they have limitations. They show how a candidate voted on a specific bill, but not why. They do not capture floor speeches, committee work, or constituent services. Researchers must supplement roll-call data with other public records: press releases, newsletters, town hall transcripts, and campaign materials.

For candidates without a legislative record, the absence of data is itself a finding. But it would be misleading to assume that a lack of votes implies a lack of positions. In South Dakota, where many candidates come from non-political backgrounds, researchers should examine their professional history, community involvement, and any public statements on key issues.

OppIntell's methodology emphasizes source-posture awareness: always noting what the public record shows, what it does not show, and what inferences are reasonable. In the 2026 South Dakota race, the voting record analysis may be most useful for Thune and any primary challenger with legislative experience. For others, the research may focus on alternative records.

Comparative Angles: How South Dakota Compares to Other States

In the last three cycles, Senate races in states with similar demographics — such as North Dakota, Montana, and Wyoming — have followed comparable patterns. Incumbent Republicans with long voting records face primary challenges from the right or general election challenges from underfunded Democrats. The voting record analysis in those states has consistently favored incumbents, as they can point to specific votes for popular local programs.

South Dakota's Senate race is less competitive than Montana's, where Democratic Senator Jon Tester has won multiple terms despite the state's Republican lean. The difference is partly due to Tester's ability to build a moderate voting record. Thune's record is more conservative, but in South Dakota, that is an asset in a general election.

For researchers, comparing South Dakota to similar states helps calibrate expectations. A voting record that would be considered moderate in a swing state is mainstream in South Dakota. This context matters when framing attack lines: what plays in Ohio may not resonate in South Dakota.

Frequently Asked Questions

What public voting records are available for South Dakota Senate candidates?

For incumbent John Thune, full roll-call records from the U.S. House and Senate are available through Congress.gov and GovTrack. For challenger Brian Bengs, no legislative voting record exists as he has never held elected office. Other candidates may have records from the South Dakota Legislature if they have served there.

How can campaigns use voting records in opposition research?

Campaigns can identify votes that are out of step with the district or state, highlight inconsistencies, and create narratives about a candidate's priorities. Voting records are often used in ads, direct mail, and debate prep to define an opponent before they can define themselves.

What are the limitations of voting record analysis?

Voting records do not show the reasoning behind a vote, nor do they capture non-legislative work. They can be misleading if taken out of context. Researchers should pair roll-call data with other public records like speeches, interviews, and campaign materials.

Are there any third-party candidates with legislative records?

As of early 2026, no third-party candidates with legislative records have announced. South Dakota law allows independent and minor-party candidates to file, but none have held legislative office in recent cycles.

How does South Dakota's Senate race compare to other states?

South Dakota's race is less competitive than many, given the state's strong Republican lean. The voting record analysis is most relevant for primary challenges. General election challengers without legislative records face an uphill battle and rely on biography and national issues.