Missouri's 3rd District Primary
Six candidates compete across three party primaries on Aug. 4 when Missouri's 3rd Congressional District election heads to the polls with incumbent Republican Rep. Bob Onder defending his seat against a fiscal conservative challenger and Democrats sorting out their own four-way contest before November.
Missouri runs a traditional partisan primary. Republicans, Democrats, and Libertarians each hold separate contests on the same day, with the top vote-getter in each party advancing to the general election. There is no top-two system, no ranked-choice voting, and no runoff mechanism. The general election follows on Nov. 3, where eight candidates are expected to appear on the ballot across all parties.
The district elects a single U.S. House member and carries a strong Republican lean. Every major forecaster rates it Solid Republican, and prediction markets put the odds of a Republican general election win at 94 percent.
Republican Primary
Onder, a physician and attorney first elected to Congress in 2024, seeks his second term. Before arriving in Washington, he served two terms in the Missouri Senate and co-founded the Missouri Senate Conservative Caucus. In the House, he sits on the Judiciary Committee, the Transportation and Infrastructure Committee, and the Education and the Workforce Committee. His legislative work in the 119th Congress includes sponsoring the Health Data Access, Transparency, and Affordability Act of 2026 and the Less Bureaucracy, Better Child Care for Student Parents Act, bills that reflect his dual background in medicine and law.
John Fraser, a certified public accountant with a master's degree in applied economics, is challenging Onder from the right on fiscal grounds. Fraser positions himself as a political outsider focused on balancing the federal budget and has drawn a sharp contrast with the incumbent, arguing on his campaign website that Onder has "voted in lockstep" with Washington while farmers and rural communities have suffered. The Fraser-Onder matchup is the only contested Republican primary race in Missouri's 3rd District this cycle.
Democratic Primary
Four Democrats filed for the seat. Two remain active heading into Aug. 4.
Bethany Mann, an environmental chemist who grew up in Foristell, Mo., as the daughter of an Air Force veteran, has run for this seat before. She campaigns on a platform centered on agriculture, manufacturing, green energy, and water infrastructure. Mann is one of the two candidates still actively competing after Paul Wilson suspended his campaign.
Tommy Holstein, a videographer by profession, rounds out the active Democratic field. He runs on a community-focused message, arguing that current leadership has "broken promises and hurt our communities."
Also on the Democratic primary ballot: Mike Conner and Paul Wilson, whose campaign has been suspended. All four names will appear on the ballot regardless of Wilson's status.
Libertarian Primary
Jim Higgins is the sole Libertarian candidate and advances to the general election automatically.
The Money Behind the Race
All candidates in the race combined raised $1,975,490 through the most recent reporting period. Outside groups have largely stayed out.
Total independent expenditures in the race reached $1,673 through June 30, 2026, according to Federal Election Commission records, a figure small enough that it carries no practical weight in the contest. No communication costs were reported.
Missouri Conservatives for Congress PAC spent $1,663, all of it in opposition to Onder. The Freedom Caucus Fund spent $10 in support of the incumbent. Those are the only two outside committees with reported activity in the race.
Every dollar of outside spending targets a single candidate: Onder faces $1,662.81 in opposition money against $10 in support, a net outside spending position of negative $1,653. No outside money has been reported for or against any other candidate in the field.
No major outside groups (party committees, super PACs, or issue organizations) have reported significant investment in either the Republican or Democratic primary as of the coverage date.
Ratings vs. Odds
Cook Political Report, Sabato's Crystal Ball, and Inside Elections all rate Missouri's 3rd Congressional District as Solid Republican. Cook and Sabato issued their ratings as of July 16; Inside Elections last updated its rating June 30. The consensus rating, aggregated as of July 23, is Solid Republican across all three.
On Kalshi, Republicans carry a 94% probability of winning the general election, with Democrats at 6%. That market had recorded 622 contracts traded as of July 26: modest volume that reflects general certainty about the November outcome rather than an active contest over the result. The real competition plays out Aug. 4, when Republican primary voters choose between Onder and Fraser, and Democratic voters pick their nominee from a four-person field.
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