The political shockwave that began in Louisiana with the defeat of Republican U.S. Sen. Bill Cassidy delivered an even larger aftershock Tuesday night in Texas. Four-term U.S. Sen. John Cornyn one of the most established Republicans in Washington and a former Senate GOP whip was decisively defeated by Texas Attorney General Ken Paxton in one of the biggest Senate primary upsets in modern Republican history.

Texas Republicans head to the polls Tuesday for one of the most closely watched runoff elections in the country, with the GOP U.S. Senate runoff between John Cornyn and Ken Paxton dominating national political attention.