The latest major poll before Tuesday’s Texas Republican Senate runoff reveals Attorney General Ken Paxton has secured a commanding lead over U.S. Senator John Cornyn.

Conducted May 21-23 among 1,018 likely GOP runoff voters by Quantus Insights, the survey shows Paxton at 52.7% and Cornyn at 43.4%, with 3.9% undecided. The effective sample size was 936, and the weighted margin of error is approximately 3.5 percentage points.

This nine-point gap represents a dramatic reversal from March’s primary, when Cornyn narrowly defeated Paxton by 1.5 points, forcing the runoff election. The poll indicates that President Trump’s endorsement of Paxton on May 19 has been a pivotal factor in the shift, though most respondents said the endorsement did not change their vote.

Among voters who were influenced by the endorsement, Paxton gained a clear advantage. The survey also found that Paxton’s lead was consistent across multiple demographic and geographic segments within the likely electorate, including rural areas, suburban communities, and voters without four-year college degrees.

Cornyn, a three-term incumbent and former Senate Majority Whip, had relied on his seniority and established relationships in the Texas GOP to secure his position. However, the current poll suggests that his traditional support base may not be sufficient to overcome Paxton’s broader coalition.

The survey, which used mobile-cell SMS outreach and modeled the Republican runoff electorate, was released as a final snapshot of voter sentiment ahead of Tuesday’s election. While turnout remains uncertain, the data points to a clear trend: Texas Republicans are deciding whether the Senate seat stays with the establishment or shifts toward President Trump’s America First agenda.