Texans chose Republican Senate nominee in runoff. Trump endorsed Paxton over Cornyn. Cornyn's primary loss forced runoff. Trump's endorsement due to 2021 impeachment vote and 2023 comments on Trump's viability. Pro-Cornyn groups outspent Paxton $16.5M to $5.9M since March 3. Cornyn acknowledged Trump's endorsement but refused to concede. 2 million of 18.7M Texas voters participated; Democrats seek to flip 4 House seats