Texas Republican Senate Primary Runoff Tests Trump's Influence Over GOP

On May 19, one week before Texas Republicans head to the polls for their Senate primary runoff, President Donald Trump made official what many had expected and others had feared: he endorsed Attorney General Ken Paxton over four-term incumbent Senator John Cornyn, calling Paxton a "MAGA warrior" and dismissing Cornyn as insufficiently loyal "when times were tough" [1]. The endorsement landed in a race already saturated with more than $120 million in spending — making it the most expensive Senate primary in American history — and immediately sharpened a question that has dogged Republicans since 2022: Does Trump's endorsement power help Republicans win primaries at the cost of losing general elections? [3]

The Candidates and What Divides Them

The policy gap between Cornyn and Paxton is narrower than the stylistic one. Both are conservative Republicans in a state Trump carried by 14 points in 2024. But the race has become a proxy war between two visions of what the party should be [11].

Cornyn, 74, has served in the Senate since 2002 and previously held the seat of Senate Republican whip. He ran on legislative effectiveness, decades of seniority, and the institutional relationships needed to advance Texas priorities in Washington. His critics within the party point to his work with Democrats on bipartisan gun legislation following the 2022 Uvalde school shooting as evidence that he is too willing to compromise [11]. Paxton's supporters also argue Cornyn should have pushed to eliminate the Senate filibuster to pass the Trump-backed SAVE Act, which would impose new voting restrictions [11].

Paxton, 63, has served as attorney general since 2015 and built a national profile as one of the most combative state officials in the country, filing dozens of lawsuits against federal agencies during the Biden and Obama administrations. He campaigned as the candidate who would fight for Trump's agenda rather than cut deals with Democrats. But Paxton carries significant baggage: a 2015 securities fraud indictment (charges later dismissed after he completed a pre-trial diversion program), a 2023 impeachment by the Texas House on charges including bribery and abuse of office (he was acquitted by the Texas Senate on a 16–14 vote), and whistleblower allegations from former staffers who accused him of misusing his office to help a campaign donor [6][7][8].

The March 3 primary produced no majority winner. Cornyn finished first with 43%, Paxton second with 41%, and U.S. Representative Wesley Hunt third with 13% [2].

Source: Texas Secretary of State

Data as of Mar 3, 2026CSV

The Runoff Math: Low Turnout and Its Beneficiaries

Texas runoff elections are defined by low participation. In 2022, roughly 1.9 million Texans voted in the Republican primary for attorney general in March, but only about 932,000 returned for the May runoff — a decline of more than 50% [5]. The pattern is holding in 2026: through the end of early voting, approximately 850,000 Republicans had cast ballots, nearly half a million fewer than the 1.3 million who voted early in the March primary [5].

Source: Texas Secretary of State

Data as of May 23, 2026CSV

Only about 4% of registered voters statewide had voted early, and in some counties the figure was below 3% [5]. The timing — after Memorial Day weekend, during graduation season — compounds the structural tendency toward low participation [5].

This dynamic favors Paxton. The University of Houston's Hobby School of Public Affairs found that 95% of Paxton's March voters planned to return for the runoff, compared to 91% of Cornyn's supporters [9]. Among voters who backed Hunt in round one, 54% now favor Paxton versus 35% for Cornyn [9]. Hunt himself endorsed Paxton on the same day as Trump's endorsement [14].

The most recent Hobby School poll, conducted in early May with 1,200 likely runoff voters and a margin of error of ±2.83 points, showed Paxton at 48% and Cornyn at 45% — a narrow lead within the margin of error [9].

Source: University of Houston Hobby School

Data as of May 5, 2026CSV

As one political analyst told NBC DFW, runoff electorates tend to skew toward "only the most ultra-mega, right, ultra-conservative primary voters" [5]. In a race where the central question is loyalty to Trump, that electorate composition matters.

The General Election Risk

The argument that has consumed Republican strategists since Trump's endorsement is straightforward: even if Paxton can win the runoff, can he win in November?

An April poll by Texas Public Opinion Research found Democratic nominee James Talarico leading Cornyn by 3 points (44%–41%) and leading Paxton by 5 points (46%–41%) [10]. A separate survey from the Texas Politics Project at UT Austin showed wider gaps: Talarico ahead of Cornyn by 7 points (40%–33%) and ahead of Paxton by 8 points (42%–34%) [10]. Likely runoff voters themselves were evenly split, 43%–43%, on which Republican would be a stronger general election candidate [9].

Source: Texas Public Opinion Research

Data as of Apr 28, 2026CSV

Talarico, a 33-year-old state representative and former educator who won his Democratic primary outright in March, raised over $27 million in the first quarter of 2026 — more than any Senate campaign in the country for that period — and has been able to focus exclusively on the general election while Republicans fight each other [12].

The Cornyn campaign has argued these numbers make the choice obvious: nominate a battle-tested incumbent who has historically overperformed fellow Republicans in Texas, or gamble on a candidate whose impeachment, securities fraud history, and whistleblower scandals will fuel a multi-million-dollar Democratic attack campaign [3].

The Steelman Case for Trump's Endorsement

Trump-aligned strategists offer a different reading of the same data. Their argument runs along several lines.

First, they point to the national environment. If 2026 is a difficult midterm for Republicans — the president's party historically loses ground — then base mobilization matters more than swing-voter persuasion in a state as red as Texas. Paxton, they argue, is better positioned to turn out low-propensity Trump voters who sat out 2022 but powered Trump's 2024 victory [3].

Second, they cite Trump's overall endorsement record. Of 176 contested primaries before September 2022 in which Trump endorsed, his candidates won 159 and lost 17, a 90% success rate [4]. In the March 2026 Texas primaries, all but five of Trump's endorsees won outright or ran unopposed [4]. His endorsement helped end Senator Bill Cassidy's career in Louisiana just days before the Paxton endorsement, with the Trump-backed candidate finishing first in a three-way race [13].

Third, they argue that Cornyn's supposed electability advantage is overstated. Both Republicans trail Talarico in general election polling, and the gap between them is within the margin of error in most surveys [10]. If both candidates face roughly the same deficit, the argument goes, the party is better served by the one who can generate MAGA enthusiasm.

The counterargument is well-documented. Research has estimated that Trump-endorsed nominees from 2018 to 2022 suffered an average 1.5-point penalty in general election performance [15]. High-profile Trump endorsees Mehmet Oz in Pennsylvania, Herschel Walker in Georgia, and Blake Masters in Arizona all lost competitive 2022 Senate races that many Republicans believe they could have won with different nominees [15].

Follow the Money: Donor Networks and Factional Lines

The financial architecture of the race reveals the fault lines within the Texas GOP more clearly than any policy debate.

Cornyn's donor base draws from the Texas establishment and the national Republican business community. Houston businessman John Nau contributed $3.9 million across the cycle to pro-Cornyn groups. Rupert Murdoch gave $200,000 directly to Cornyn's campaign on New Year's Eve. The Perot family donated hundreds of thousands of dollars across Cornyn's various campaign committees [3].

The pro-Cornyn super PAC raised $9.5 million in the first quarter of 2026, compared to $2.1 million for the pro-Paxton super PAC [3]. On the airwaves, Cornyn and his allies outspent Paxton's side by roughly 17-to-1 [3].

Paxton's fundraising has been smaller and more ideologically driven. He told supporters before launching his Senate campaign that he believed he could win if he raised $20 million, but he has fallen well short of that target [3]. Several major Texas businessmen who spent millions backing Paxton's attorney general campaigns have not contributed to his Senate bid, a sign that his legal history has made some traditional donors cautious [3].

The cross-pressures are visible in individual donors. Midland oilman Douglas Scharbauer, from a prominent North Texas horse breeding and racing family, maxed out his direct contribution to Cornyn at $7,000 — but had earlier given $250,000 to a pro-Paxton super PAC [3]. That kind of hedging reflects a business community caught between institutional loyalty and ideological alignment.

The oil and gas sector, historically a pillar of Texas Republican politics, has largely backed Cornyn through direct contributions and bundled fundraising. Energy executives appear in his donor rolls repeatedly across four Senate cycles [3]. Paxton's support from the sector has been thinner, concentrated among smaller operators and ideologically motivated donors rather than the major integrated companies.

Senate Republicans Sound the Alarm

Trump's endorsement of Paxton produced an unusually blunt backlash from his own party's senators. Senator Lisa Murkowski of Alaska said she was "supremely disappointed" and warned that the endorsement "puts that seat in jeopardy" [16]. CNN reported that GOP senators and aides described recent White House actions, including the Paxton endorsement, as "damaging blunders" that they fear will cost them control of the chamber [17].

The Philadelphia Inquirer reported that Republican senators were "livid" at the endorsement, noting that Senate leaders worry the combined effect of Cassidy's loss in Louisiana and the potential loss of Cornyn in Texas will complicate efforts to pass legislation [16]. By pushing out incumbents over perceived disloyalties, Trump has expanded the number of "free agents" in the Senate — retiring or defeated senators who are suddenly more willing to oppose his priorities [17].

The Louisiana precedent is instructive. When Cassidy lost his primary on May 16 after Trump endorsed Representative Julia Letlow, Cassidy signaled in his concession speech that he would spend his remaining months in office being more openly critical of the White House [13]. He became the first incumbent senator to lose renomination since Richard Lugar in 2012 [13]. If Cornyn loses the runoff, he would join that short list, and his remaining months in the Senate — or his potential role as a vocal critic — could further complicate Trump's legislative agenda.

What a Cornyn Loss Would Mean

The documented pattern after Trump endorsement defeats is not one of reconciliation. When Trump-backed candidates lost general elections in 2022 — particularly Oz, Walker, and Masters — Senate Republican leadership publicly distanced themselves from the endorsement decisions. Senate Minority Leader Mitch McConnell openly blamed "candidate quality" for the party's failure to flip the Senate, a barely veiled criticism of Trump's choices [15].

If Paxton wins the runoff and then struggles in November against Talarico, the national party faces a difficult decision: pour resources into defending a deeply flawed candidate in a state Republicans have held for decades, or quietly triage the seat. The National Republican Senatorial Committee has historically backed its nominees regardless of primary circumstances, but the scale of resources required — and the opportunity cost of defending Texas rather than targeting Democratic seats — would represent a significant strategic burden.

If Paxton wins the runoff and wins the general election, the calculation reverses entirely: Trump's endorsement would be vindicated, his critics in the Senate caucus would be weakened, and the case for Trump's political judgment would be strengthened heading into the next cycle.

The Broader Pattern

The Texas runoff sits within a 2026 primary season that has repeatedly tested Trump's influence over the Republican Party. His endorsement helped oust Cassidy in Louisiana and defeated several Indiana state lawmakers who had crossed him [15]. In Kentucky, his endorsement of Representative Andy Barr effectively ended the open Senate primary [15].

But his record is not unblemished. Research on Trump-endorsed nominees from 2018 through 2022 found that raw win rates in primaries overstate his causal impact — many endorsements go to incumbents, unopposed candidates, or heavy favorites, and some come late enough that they are unlikely to have changed the outcome [15].

The Texas race is different because Trump endorsed against a powerful incumbent in a state where the general election is no longer guaranteed. Talarico's fundraising prowess, the national midterm environment, and Paxton's personal liabilities create a combination that has made even Trump's allies nervous.

As Texas Republicans vote on May 26, the question is not just whether Trump can pick winners in primaries. It is whether the Republican Party can afford the general election costs of letting him try.