The Republican primary for Missouri’s 10th Senate District has gone from routine to raw, as outside groups and rival operatives fire off attack mailers over a 2025 episode in which state Rep. Tricia Byrnes tested the 988 suicide hotline from the Capitol. What started as a procedural check on 988 response times has morphed into the defining storyline of a race that will be settled in the Aug. 4 primary.
The seat opened after Sen. Travis Fitzwater accepted a post leading the Missouri Technology Corporation and announced he would not seek re-election. The two top Republicans on the August ballot are Tricia Byrnes and Mike Deering, according to the Missouri Secretary of State. The Missouri Technology Corporation confirmed Fitzwater’s hire in February, and Deering is the longtime executive vice president of the Missouri Cattlemen’s Association, per The Beef Site.
Attack Mailers Target 988 Test
Outside group Cut the Bull PAC has been flooding mailboxes with pieces accusing Byrnes of lying to police and filing a fraudulent police report after the 988 texts, according to reporting from the Missouri Independent. Byrnes and her campaign counter that she only sent texts to the 988 line to demonstrate automated responses and to call attention to long waits.
Money and Outside Groups
Outside spending and committee cash are already shaping who gets heard in the district. Recent filings and quarterlies cited by local outlets show Cut the Bull and other committees, along with the two candidate committees, reporting mid–five-figure to low–six-figure totals. That is fueling the early wave of mail pieces and digital ads, according to The Missouri Times.
Legal Questions Remain
Cole County Prosecutor Locke Thompson reviewed the 988 texts and later announced he would not file criminal charges, saying Byrnes appeared to be acting in good faith while conducting what she described as a legislative test, according to the Kansas City Star. Even so, the episode triggered a state patrol response and remains a central attack line in the primary.
What’s At Stake
The winner of the Republican primary is widely expected to determine whether the 10th District remains a safe GOP seat and which Democrat — John Wells or Pablo John Los — the eventual Republican nominee will face in November, per the Secretary of State’s filings from the Missouri Secretary of State.
Local operatives say the campaign’s combative tone and the flood of outside spending could play a big role in who actually shows up on Aug. 4. With the primary less than three weeks away, both campaigns and their allied committees are expected to keep trading ad buys and mailers as they try to define the choice for a district that stretches from suburban St. Charles into nearby rural counties. Expect the pace to pick up as donors and PACs decide which lane to double down on, per BallotWire.
