Texas Attorney General Ken Paxton has defeated longtime U.S. Senator John Cornyn in the Republican Senate primary runoff, delivering one of the biggest political upsets of the 2026 election cycle. The closely watched contest drew national attention as it highlighted the growing divide within the Republican Party between establishment conservatives and candidates aligned with former President Donald Trump’s political movement.

Paxton secured victory after running a campaign focused on conservative grassroots voters and strong support for Trump-era policies. Cornyn, who has represented Texas in the Senate for more than two decades, struggled to maintain support among Republican primary voters despite his experience and influence in Washington.

Political analysts say Trump’s endorsement of Paxton played a major role in the outcome of the race. The result is being viewed as another sign of the continued strength of Trump-backed candidates in Republican primaries across the country. With the victory, Paxton is now expected to become the Republican nominee for the U.S. Senate seat in the November general election.

The Senate race overshadowed several other important statewide primary contests in Texas, including races for governor and attorney general. Governor Greg Abbott did not take a public side in the Senate runoff and largely stayed away from the heated campaign battle between Paxton and Cornyn. The attorney general race became more competitive after Paxton decided not to seek re-election for his current position. Multiple Republican candidates entered the contest hoping to succeed him.

The outcome of the Senate primary could have wider national implications as both parties prepare for the general election season. Republicans are aiming to maintain their dominance in Texas, while Democrats believe internal divisions within the GOP could make statewide races more competitive.

Political observers say Cornyn’s defeat marks a significant shift in Texas Republican politics, where outsider-style campaigns and populist messaging continue to gain momentum among conservative voters. The November election is now expected to attract major national attention as Texas becomes a key battleground in the broader fight for control of the U.S. Senate.