Texas Attorney General Ken Paxton defeated longtime Senator John Cornyn in a Republican runoff primary, unseating an incumbent who had served in the Senate for 23 years.

The race, one of the most expensive Senate primaries in U.S. history, sets up a November general election between Paxton and Democratic state legislator James Talarico.

Paxton, a controversial figure who campaigned as a populist aligned with Donald Trump, overcame Cornyn despite being heavily outspent.

Cornyn, a senior Senate Republican leader, had initially led in the first round of voting but failed to secure a majority, forcing the runoff, the BBC has reported.

The outcome is expected to shape control of the Senate and reflects ongoing divisions within the Republican Party between establishment figures and Trump-aligned candidates.