Key events31m agoCornyn tries to hold on to Texas Senate seat in runoff with Trump-backed PaxtonShow key events onlyPlease turn on JavaScript to use this featureDavid SmithKen Paxton, the state attorney general, takes on four-term incumbent John Cornyn on Tuesday in the ugliest primary election of the year. The winner of the Republican Senate runoff in Texas will contest November’s general election against Democrat James Talarico.Paxton and Cornyn have spent months coveting the most valuable endorsement in Republican politics: Donald Trump. Last week, scandal-plagued Paxton got it, with the US president describing him as “a true Maga warrior”.Supporters in McKinney, Texas, agree. “Paxton is more conservative,” said Jim Tubbesing, 77, strolling in Paxton’s home town, a tranquil vision of Americana with cute antique shops, trendy bistros and a walkable historic downtown exuding 19th-century charm.“He has been good for Texas. I vote for the policy, not the fact that he’s alleged to have done something.” Tubbesing, calling Cornyn a “Rino: Republican in name only.”The runoff is not fundamentally about policy, since Cornyn and Paxton would vote the same way on almost every piece of legislation. It is more about vibe and style, and has huge implications for Texas, control of the US Senate, and the future direction of the Republican party.Cornyn, a former Texas attorney general and state supreme court justice, is widely seen as a last gasp of the Republican establishment. In a primary on 3 March, he narrowly beat Paxton, a far-right hardliner who has been impeached and indicted. But those aggressive stances on immigration and culture war issues appeal to the party’s base. But both men qualified for the runoff.Cornyn tries to hold on to Texas Senate seat in runoff with Trump-backed PaxtonHello and welcome to the US politics live blog.Texans are voting for a Republican nominee for US Senate in Tuesday’s runoff election, following Donald Trump’s late bid to influence the race in his latest effort to rid the GOP of less devoted leaders.The president’s endorsement of state attorney-general Ken Paxton over four-term senator John Cornyn gave the challenger a late boost, leaving Cornyn at risk of becoming the first Republican senator in Texas history to seek the party’s nod and lose.It comes despite Cornyn’s campaign and allied groups spending roughly $90m in advertising since last year, the vast majority of it attacking Paxton, AP reported.It’s the latest GOP contest where Trump has sought to punish a Republican he sees as insufficiently loyal. This month, he has successfully backed challengers to incumbents in Louisiana, Kentucky and Indiana - a sign of his enduring influence among primary voters.Paxton’s campaign and a pro-Paxton super PAC began airing ads promoting the endorsement within 24 hours of Trump’s announcement. Cornyn acknowledged Trump’s move would have an impact but said he wasn’t giving up.“I know who gets to choose our senators, and it’s the people of Texas,” he said hours after the endorsement. The winner will run in November against the Democratic candidate James Talarico .Tuesday’s runoffs also will decide Democratic US House nominees for districts in Dallas and Houston that overwhelmingly support Democrats and a San Antonio-area seat the party hopes to flip.In other developments: