Cornyn and Paxton Face Off in Final Day of Texas Republican Senate Primary Runoff

Texas Republicans go to the polls on May 26 to settle what has become the costliest and most consequential intra-party fight in U.S. Senate history. Incumbent Senator John Cornyn, who has held his seat since 2002, faces Attorney General Ken Paxton in a Republican primary runoff that has consumed roughly $135 million in combined advertising, drawn a presidential endorsement with one week left on the clock, and forced both candidates into a scorched-earth messaging campaign that may leave the eventual nominee damaged heading into November [1][2].

The race is a stress test for two competing theories of Republican politics in the Trump era: whether institutional seniority and legislative experience still matter in a party that increasingly rewards loyalty to a single leader, or whether the MAGA movement's gravitational pull is now strong enough to topple a four-term senator in the second-largest state in the country.

How We Got Here: The March Primary

Cornyn and Paxton emerged from a three-way March 3 primary in which neither cleared the 50% threshold needed to avoid a runoff. Cornyn led with 42.0% to Paxton's 40.5%, with U.S. Representative Wesley Hunt collecting 13.5% [3]. That razor-thin 1.5-point margin — just over 30,000 votes — set up the May 26 runoff.

The March primary drew approximately 1.3 million Republican voters [4]. By contrast, the runoff's early voting period produced roughly 820,000 Republican ballots cast by mail and in person, representing about 4.4% of registered voters [4][5]. That retention rate — roughly 63% of primary early voters returning for the runoff — is high by historical Texas runoff standards, reflecting the intensity of the contest.

The Money Race: A Record-Breaking Imbalance

The financial disparity between the two campaigns has been staggering. In first-quarter 2026 filings, Cornyn raised approximately $9 million across all his committees and held $8.2 million in cash on hand. Paxton raised $2.2 million and held $2.6 million [6]. The gap widened further when super PAC money entered the picture: the pro-Cornyn Texans for a Conservative Majority raised $9.5 million in Q1, compared to $2.1 million for the pro-Paxton outside group [6].

In the March primary, pro-Cornyn forces spent roughly $69 million on advertising — approximately 17 times the $4 million spent by Paxton and his allies [1]. The runoff narrowed that ratio to about four-to-one, with $19.9 million in pro-Cornyn ad spending versus $5.1 million for the Paxton side through mid-May [1].

Source: Texas Tribune / AdImpact

Data as of May 25, 2026CSV

Houston businessman John Nau has been identified as a central figure in the pro-Cornyn outside money operation, contributing millions to the super PAC backing the incumbent [7]. Senate Republican leadership, including Majority Leader John Thune, has also invested heavily in protecting Cornyn's seat [2].

Despite being massively outspent, Paxton has remained competitive — a fact that underscores the limits of money in a race where Trump's brand carries independent weight.

Trump's 11th-Hour Endorsement

The race's decisive moment may have arrived on May 19, when President Trump endorsed Paxton with one week of voting remaining [8]. Trump had remained neutral through the March primary, telling supporters he "liked all three candidates." After the runoff was set, he promised to endorse "soon" — then waited more than two months [9].

Trump's endorsement statement called Paxton "a true MAGA Warrior who has ALWAYS delivered for Texas" and cited two specific policy positions: Paxton's support for eliminating the Senate filibuster and passing the SAVE Act, a voter eligibility verification measure [8][10]. Trump also noted that Cornyn "was not supportive of me when times were tough" — a reference to Cornyn's criticism of Trump ahead of the 2024 presidential campaign [11].

The endorsement triggered an immediate cascade. Wesley Hunt, whose 13.5% primary vote share represents the most sought-after bloc of persuadable Republican voters, endorsed Paxton the same day [12]. The combined Trump-Hunt alignment gave Paxton what amounts to a unified MAGA front heading into election day.

Cornyn's response was measured. "I think that ship has probably sailed," the senator told reporters, adding that his campaign would maintain "a packed campaign schedule" across Texas metro areas [10].

The Conservative Credential Fight

Paxton's campaign has built its case against Cornyn around a handful of Senate votes that, in the attorney general's framing, reveal an insufficiently conservative record.

The most prominent target is the Bipartisan Safer Communities Act of 2022, the first major federal gun safety legislation in decades. Cornyn helped negotiate and shepherd the bill, which enhanced background checks for young gun buyers and provided funding for state crisis intervention programs. Paxton has repeatedly branded Cornyn an "anti-gun establishment politician" for his role in the law [13][14].

Beyond guns, Paxton has attacked Cornyn for supporting U.S. aid to Ukraine, for his past openness to the DREAM Act providing a path for some undocumented immigrants brought to the U.S. as children, and more broadly for a willingness to work with Democrats that Paxton characterizes as capitulation [13].

Cornyn's actual conservative ratings tell a more complicated story. His lifetime American Conservative Union score is 93% [15]. Heritage Action for America, which grades on a stricter curve, has rated him as the ninth most conservative among Republican senators, at 86% in the current Congress [15]. But that aggregate masks significant variation: Heritage scores for Cornyn have ranged from 35% in the 118th Congress to 96% in the 119th, reflecting specific votes that either aligned with or diverged from the conservative movement's priorities [15].

The National Journal ranked Cornyn the second most conservative senator based on his 2011-2012 voting record, with a 93.8% composite conservative score [15]. By most quantitative measures, Cornyn is well to the right of the Senate median — but in a primary where the relevant comparison is not the Senate as a whole but the expectations of Texas Republican primary voters, those numbers have not insulated him from Paxton's attacks.

The Case for Cornyn: Seniority and Results

Cornyn's defenders argue that his two-plus decades in the Senate have produced concrete policy outcomes that a freshman senator — regardless of ideology — cannot replicate. He has chaired the National Republican Senatorial Committee twice, served on the Judiciary and Intelligence committees, and accumulated the kind of institutional relationships that translate into legislative influence [2].

Former U.S. Representative Ted Poe, backing Cornyn, has argued that "Texas benefits from the seniority Cornyn has accrued" and that the senator has been "a reliable partner in the upper chamber" [2]. Senate Majority Leader Thune's endorsement carries the implicit message that Republican leadership views Cornyn as essential to its governing coalition [2].

The skeptic's counter is fair: what, specifically, has that seniority delivered? Cornyn's most visible bipartisan achievement — the gun safety bill — is the very legislation his opponent uses against him. His role in judicial confirmations and behind-the-scenes negotiations is real but harder to campaign on. The tension between legislative effectiveness and primary electability is the central paradox of Cornyn's candidacy.

The Case Against Paxton: Legal Baggage and General Election Risk

Paxton enters the runoff carrying legal and ethical liabilities that are unprecedented for a major-party Senate nominee in recent Texas history.

In 2015, a state grand jury indicted Paxton on two counts of securities fraud (first-degree felonies) and one count of failing to register with state securities regulators, stemming from accusations that he encouraged other legislators to invest in a McKinney-based company without disclosing that the firm was paying him to promote its stock [16]. After years of delays, Paxton reached an 18-month pre-trial agreement under which prosecutors would drop the charges in exchange for full restitution to victims, 100 hours of community service, and 15 hours of legal ethics education [16].

In 2023, the Texas House impeached Paxton on articles alleging he gave preferential treatment to a donor, misapplied public resources, obstructed justice, and made false statements. The Texas Senate voted 16-14 to acquit him on all articles, ending his suspension from office [17]. The acquittal did not resolve the underlying allegations — it merely meant the Senate declined to remove him.

Pro-Cornyn advertising has hammered these vulnerabilities relentlessly, with ads attacking Paxton as "incompetent, corrupt and adulterous" [1]. The strategic calculation is straightforward: Cornyn's allies spent tens of millions of dollars airing allegations against Paxton that Democratic nominee James Talarico can repurpose at zero cost in the general election [18].

The General Election Shadow

Multiple polls show that either Republican nominee would face a competitive general election against Talarico — but Paxton's numbers are consistently weaker.

A Texas Southern University poll (April 22-May 6, 1,223 likely voters) found Cornyn leading Talarico 45%-44%, while Paxton and Talarico were tied at 45% each [18]. A University of Texas/YouGov survey showed Talarico leading Paxton 42%-34% and leading Cornyn 40%-33% [18]. Slingshot Strategies/Texas Public Opinion Research found Talarico ahead of Paxton 46%-41% and ahead of Cornyn 44%-41% [18].

Source: Multiple Polls (TSU, UT/YouGov, Slingshot)

Data as of May 20, 2026CSV

Republican analyst Mark Jones warned that the primary has created "collateral damage," with the candidates having done "Democrats' dirty work" by damaging each other's images [18]. Some Republican strategists have expressed concern that a Paxton nomination could produce the party's first statewide loss in Texas since 1994 [18]. One poll suggested a Paxton nomination could drag down Republican margins by five to eight points in down-ballot races [19].

These numbers represent a remarkable situation for a state that has not elected a Democratic senator since 1988.

The counter-argument from Paxton supporters is that general election polls this far out are unreliable, that Texas's structural Republican advantage (Trump carried the state by roughly 14 points in 2024) provides a substantial buffer, and that Talarico — a Democratic state representative whom GOP operatives have already begun attacking as too liberal for Texas — would face his own vulnerabilities in a general election campaign [20].

Early Vote Geography: A Divided Map

The early voting data reveals a geographic split that mirrors the candidates' respective coalitions.

Cornyn's metro strongholds retained early voters at higher rates than Paxton's suburban and exurban bases. Travis County (Austin), where Cornyn won by 24 points in March, kept nearly 80% of its Republican early vote from the primary. Dallas County, where Cornyn won by 18 points, retained about 70% — 45,974 early votes in the runoff versus 64,948 in the primary [5].

Paxton-friendly counties showed lower retention but higher turnout rates among registered voters. Montgomery County, where Paxton won by 27 points in March, retained about 60% of its early vote but posted roughly 6% turnout among registered Republican voters — higher than the 3% rate in Cornyn-favoring metro counties [5].

Source: Tyler Morning Telegraph / TX SOS Data

Data as of May 25, 2026CSV

The Cornyn campaign has explicitly sought high turnout, stating: "Unlike Ken Paxton, we want high turnout. We are working to turn out as many Republicans as possible" [5]. The implication is that Paxton's path depends on a smaller, more ideologically motivated electorate — a common dynamic in runoff elections, where lower turnout historically favors the more insurgent candidate.

Total Republican runoff turnout is projected somewhere between 1 million and 1.25 million, with potential for up to 1.5 million if election day participation surges [4].

The March Geography and Trump's Map

Paxton's primary coalition tracked closely with Trump's strongest counties. In Texas counties where Trump won 80% or more of the 2024 vote, Paxton led Cornyn 45%-40% [11]. In more moderate Trump counties (50-80%), Cornyn led by about one percentage point. In counties that Kamala Harris won, Cornyn led 44%-40% [11].

This geographic alignment is central to understanding Trump's endorsement. Paxton's voters are Trump's voters. The endorsement was not an ideological statement so much as a ratification of an existing coalition — one built on cultural conservatism, anti-establishment sentiment, and personal loyalty to the president.

What Happens Next

The runoff concludes a primary season that has cost the Republican Party of Texas both money and unity. State GOP Chair Abraham George called for an end to negative advertising before the runoff, a plea that went unheeded by both sides [21]. Multiple Republican officials have publicly worried that the bruising contest will benefit Talarico regardless of which candidate prevails [2].

If Cornyn wins, he returns to Washington with diminished standing among the party's Trump-aligned base but with his institutional power intact and a relatively straightforward general election path.

If Paxton wins, he enters the general election as a first-time Senate candidate carrying the weight of a $135 million negative ad campaign — much of it funded by his own party — against a Democratic opponent in a state where general election polls already show a competitive race. The question of whether Texas's structural Republican lean can absorb those liabilities will be tested in November.

Only two incumbent U.S. senators from Texas have lost a primary in the last 100 years [11]. Whether Cornyn becomes the third depends on whether Trump's endorsement and Paxton's MAGA coalition can overcome a four-to-one spending disadvantage and a decade of legal controversy — all in a single day of voting.