Many voters in Columbia will cast their congressional ballots for the first time Aug. 4 in the newly redrawn U.S. District 3.
In the Republican primary, the race pits incumbent Rep. Bob Onder against John Fraser, a certified public accountant and economist conservative.
After the withdrawal of candidate Paul Wilson, the Democratic primary has narrowed to two active candidates, Bethany Mann and Tommy Holstein.
The new congressional map, approved at the urging of President Donald Trump by the Republican-controlled Missouri General Assembly during a special legislative session last fall, moved much of Columbia from the 4th District into the 3rd. Onder already represents much of southern Boone County.
Thousands of Boone County voters now live in a congressional district that stretches from central Missouri to the St. Louis suburbs, where the primary is expected to play a major role in determining who will represent them in Congress.
District 3 includes those in the southern half of the city, the University of Missouri campus and most neighborhoods south of Broadway. Residents north of Broadway and in northern Boone County are in the new 5th Congressional District, which extends north and west to Kansas City.
The new maps leave Columbia split almost in half between the two districts. That reflects a goal of Republicans to divide Democratic votes to ensure one additional Republican seat is added to the state’s current 6-2 breakdown in favor of the GOP.
Republican lawmakers argued that the map better reflects Missouri’s electorate, while Democrats and voting rights advocates challenged it as an unconstitutional partisan gerrymander. After months of legal challenges, the Missouri Supreme Court upheld the map, allowing it to be used in this year’s primary election.
Onder started his political career in 2006 when he was elected to the Missouri House of Representatives. He then won election to the Missouri Senate in 2014, where he served as assistant majority floor leader and became known as one of the chamber’s leading conservative voices on issues including taxes, abortion and government spending. He served two terms before leaving the Senate in 2022 because of term limits.
In 2024, Onder defeated Democrat Bethany Mann to earn the congressional seat. He serves on the House Judiciary Committee, the House Transportation and Infrastructure Committee and the House Education and Workforce Committee.
In Congress, Onder has continued to be a strong advocate for positions on issues he was well known for while in the Missouri General Assembly: fighting illegal immigration, opposing abortion, protecting gun rights, opposing liberal policies and promoting lower taxes.
Onder has also been a supporter of Missouri’s congressional redistricting effort, arguing the state’s congressional delegation should better reflect Missouri’s Republican electorate.
“We are a Republican state,” Onder said in an interview with St. Louis Public Radio. “Republicans have super majorities in the Missouri House and the Missouri Senate. Republicans hold all of our statewide elected offices, including, of course, governor. And I believe that we should pass a congressional map that reflects the values of the state of Missouri.”
He earned a medical degree from Washington University School of Medicine and a law degree from Saint Louis University. In 1992, he opened a private allergy, asthma and clinical immunology practice, where he treated patients for more than 30 years.
Onder faces John Fraser, who describes himself as a constitutional and free-market conservative.
“I’m for putting more money in the pockets of Missourians,” Fraser said in an interview.
He said his campaign focuses on reducing federal spending, balancing the federal budget and opposing tariffs, which he argues have raised costs for Missouri families and hurt farmers. He said his background as a CPA gives him experience managing budgets and understanding fiscal policy.
While acknowledging Onder’s advantages in fundraising and name recognition, Fraser said voters should closely examine his legislative record.
“It’s a David and Goliath,” Fraser said. “He’s been in politics 20 years. He’s got a lot more money than I do. ... But I keep reminding people David won.”
Fraser also questioned the timing of Missouri’s redistricting process.
“It is kind of an interesting coincidence,” he said, adding that many voters he met while campaigning were unaware they had been moved into the 3rd Congressional District.
Among the Democratic candidates, Mann, who lives in St. Peters, is a technology specialist who works with laboratories in the agriculture, energy, pharmaceutical and environmental industries. She earned a degree in chemistry and began her career as an intern with the U.S. Environmental Protection Agency before moving into the private sector.
She said her campaign is centered on strengthening Missouri’s middle class through investments in education, infrastructure and affordable health care. She supports fully funding public schools, expanding broadband access, repairing roads and bridges, and increasing federal investment in rural infrastructure.
Health care is another cornerstone of her campaign. Mann said she supports expanding affordable healthcare access, improving mental health services, protecting reproductive rights and increasing access to telehealth.
She also advocates for expanding voting access through mail-in ballots and additional early voting opportunities, and she supports renewable energy initiatives and environmental protections.
“As a working mom with toddlers,” her campaign states, “she understands the hard work necessary to be successful in both life and on the job.” Every Missourian deserves quality education, affordable healthcare and economic opportunity, she said.
Holstein is running on a progressive platform centered on what he describes as building “an economy that works for all of us.” He argues that wages have failed to keep pace with worker productivity while corporate profits and wealth inequality continue to grow.
His campaign calls for raising the minimum wage, closing tax loopholes benefiting billionaires, strengthening labor unions through the PRO Act and breaking up monopolies that he says have driven up costs for consumers.
Holstein also supports Medicare for all, increasing incentives for first-time homebuyers and lowering everyday costs for working families.
Education is another major focus of Holstein’s campaign. He advocates fully funding public schools, expanding tuition-free community colleges, trade schools and apprenticeships, and preparing students for an economy increasingly shaped by artificial intelligence.
Unlike many congressional candidates, Holstein has also made regulating artificial intelligence and large technology companies a centerpiece of his campaign. He supports an AI Bill of Rights, stricter oversight of data centers and limits on tax incentives for technology companies that do not create permanent jobs, arguing Missouri should protect its natural resources while encouraging responsible innovation.
The Democratic nominee will advance to the November general election to face the Republican nominee.