Texas Senate Primary Between Cornyn and Paxton Becomes One of Most Expensive in U.S. History
Why It Matters
The Texas Republican Senate primary runoff between incumbent Sen. John Cornyn and Attorney General Ken Paxton has set a national record for primary spending, raising questions about the role of megadonors, super PACs, and untraceable dark money in shaping the outcome of major state elections. The contest, set to conclude in a May 26 runoff, illustrates how outside money can flood a single-party primary and define the information environment for millions of voters.
What Happened
More than $120 million has been spent on advertising across both rounds of the Cornyn-Paxton primary contest, with roughly $21 million concentrated in the runoff phase alone, according to data from media tracking firm AdImpact. That total makes the race the most expensive party primary in the country’s recorded history.
The spending has flowed through a web of candidate campaigns, political action committees, joint fundraising committees, and tax-exempt nonprofits — commonly called dark money groups — that are not required to identify their financial backers. Even some PACs that do have disclosure requirements were funded primarily by dark money organizations, leaving the ultimate source of millions in spending unidentified.
Cornyn has held a commanding financial advantage throughout the contest. His campaign and associated joint fundraising committees raised approximately $26.5 million this cycle, spending around $23.4 million, with total ad spending reaching $24.1 million. Paxton’s operation has spent considerably less, though both camps have aired extensive negative advertising targeting the other candidate.
By the Numbers
- $120M+ — Total advertising expenditures across the full primary contest
- $21M — Spending in the runoff phase alone
- $35.6M — Amount raised by Texans for a Conservative Majority, the largest pro-Cornyn super PAC
- $26.5M — Total raised by Cornyn’s campaign committees this cycle
- $6.4M — Cornyn campaign ad spending in the runoff period
Key Donors and Outside Groups
Cornyn’s donor base spans from longtime Republican establishment figures to major media and business figures. Former President George W. Bush contributed $5,000 to Cornyn — his first federal political donation in Texas since the 2022 cycle, when he also gave $125,000 to his nephew George P. Bush during that year’s attorney general primary against Paxton. Media executive Rupert Murdoch contributed $200,000 on New Year’s Eve.
Real estate developer Ross Perot Jr., who chairs the Perot Companies and serves as board chair of the U.S. Chamber of Commerce, along with his wife Sarah, contributed hundreds of thousands of dollars to Cornyn’s various committees. Perot initially backed Nikki Haley in the 2024 presidential primary before pivoting to support Donald Trump.
The dominant outside spender on Cornyn’s behalf has been Texans for a Conservative Majority, a super PAC that raised $35.6 million and spent roughly $32.8 million this cycle. The group has ties to Trump’s political orbit through a senior adviser who played a prominent role in Trump’s 2024 presidential campaign. The PAC has made multiple seven-figure advertising purchases directed against Paxton.
Cornyn’s campaign also employed a notable legal strategy using joint fundraising committees to purchase television advertising at the reduced rates available only to candidate accounts — a relatively novel approach that amplified his financial edge over Paxton in hard-dollar terms.
Zoom Out
The Cornyn-Paxton race reflects a broader national pattern in which Republican primaries — particularly in large Sun Belt states — have become multimillion-dollar battles fought as much through super PACs and dark money networks as through traditional grassroots organizing. Texas has seen escalating outside spending in successive cycles, and the 2026 contest now stands as a benchmark for primary campaign finance nationally.
The race has also highlighted ongoing debate over disclosure requirements in federal elections. Dark money spending by tax-exempt nonprofits remains lawful under current campaign finance law, but the scale of untraceable funds in a single primary has drawn renewed scrutiny to existing rules. Immigration and border policy remain defining issues in Texas federal races, as seen in recent disputes over federal land use near El Paso and housing policy affecting noncitizens in communities across the state.
What’s Next
Texas Republican primary voters will cast their final ballots in the Cornyn-Paxton runoff on May 26. The winner will advance to the November 2026 general election as the heavy favorite in a state that has not elected a Democrat to statewide office since 1994. Spending is expected to continue accelerating through election day as both sides make final advertising pushes.