Ken 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.

Jon Taylor, a political science professor at UT San Antonio, said of Cornyn: “He’s like the last of the old-guard Republicans in this state, someone who could – in some respects – trace his lineage back to both George Herbert Walker Bush and George W Bush.”

Victory for Paxton, meanwhile, would continue Trump’s winning streak of endorsements and testify to his enduring grip on the Republican party. But given Paxton’s liabilities, it could also jeopardise a Senate seat against Talarico, a state legislator with a groundswell of popularity, looking to become the first Democrat in more than 30 years to win statewide office in Texas.

Cristina Tzintzún Ramirez, a former Democratic candidate for Senate who is now a partner at Ascend Strategy Labs, a social justice consulting firm in Austin, said: “It’s one of the most exciting races in the country and, if Ken Paxton becomes the candidate, Talarico has a shot. That wouldn’t just change the political outcome of our state for an election cycle; that would start to change the political outcome and possibilities for our country for a generation. That’s what this Senate race means.”

Texas is the second biggest state in the US. For decades, the Republican party here was moulded in the image of the Bush family: pragmatic, business-friendly and focused on the economy and free trade. Cornyn has helped the party raise millions of dollars and worked with Democrats on bipartisan bills.

Cal Jillson, a professor of political science at Southern Methodist University (SMU) in Dallas, described Cornyn as a “calm, serious, problem-oriented politician” who works to resolve issues across the aisle. But that willingness to govern is precisely what has made him a target.

In 2022, Cornyn helped negotiate a bipartisan gun safety bill in the wake of the Uvalde school massacre. In the eyes of Trump’s Make America Great Again (Maga) movement, it was an unforgivable betrayal. Republican consultant Vinny Minchillo said: “Cornyn certainly at the time knew this would come back to haunt him but felt like he made the best deal he could make for gun owners.”

He has never faced a challenger like Paxton. Long before Trump descended an escalator at Trump Tower in 2015 to launch his run for the White House, Paxton was pioneering the grievance-fuelled, anti-establishment politics that would become the hallmark of Maga.

Brandon Rottinghaus, a political science professor at the University of Houston, said: “Paxton was Donald Trump before Donald Trump was. He was in the vanguard of the Tea Party movement, which was a major spur for the Maga movement nationally.

“Even from his time as a state legislator in the early 2010s, he was willing to push the establishment and didn’t much care about his personal reputation. He was more concerned with establishing an ideological foothold in the Republican party.”

First elected state attorney general in 2014, Paxton sought to position himself as a national leader on the far right, launching some of the first criminal investigations in the US over abortion bans and gender-affirming care for transgender youth. He also led a lawsuit attempting to overturn Trump’s loss to Joe Biden in 2020, an effort the US supreme court rejected.

But he comes with gigantic political baggage. Paxton was impeached in 2023 after being accused of corruption, and reported to the FBI. He was later acquitted in a trial in the Texas senate, where his wife was a state senator but not allowed to cast a vote.

Paxton was also indicted on charges of felony securities fraud that could have led to a prison sentence, but the case was dismissed after a 2024 pre-trial diversion agreement. And last year his wife of 38 years, Angela Paxton, filed for divorce “on biblical grounds”, citing adultery.

But back in McKinney, many are sticking with the hometown hero. At the Palace Barber Shop, which dates back to 1892 and where pictures of Teddy Roosevelt, Ronald Reagan and Trump – fist raised after an assassination attempt – adorn the bare brick wall, barber Beau Bonner, 57, said: “I don’t think … Paxton’s doing a good enough job on the immigration invasion, but I’m still gonna vote for him. Cornyn is not second-amendment friendly; he’s a gun-grabber.”

Asked about the main issues in the election, Bonner said: “It’s the guns and it’s the immigration. Everybody’s familiar with Paxton’s scandals.”

Keenly aware of those scandals, Republican leaders pleaded with Trump to stay out of the race while Cornyn desperately tried to woo the president, for example by introducing a bill to name a future interstate highway after him. But it was all in vain. Trump threw his weight behind Paxton, perhaps aware that his own legal and sexual dramas have raised the bar for what constitutes a career-ending offence.

Mark Jones, a political science professor at Rice University in Houston, observed: “There’s a whole host of baggage there that roughly half of Republican primary voters are ignoring, or they see and don’t believe it, or they see it and don’t care because Paxton has used his position as the attorney general of Texas to further the conservative agenda at the national, state, and local level in a powerful way.”

The general electorate, including suburban Republican women and independent voters, may take a different view, however. Jones added: “If you step back as a neutral observer and think about November 2026, it’s pretty clear that Paxton is the weaker candidate.

“He’s deeply flawed: his status as a serial adulterer; his income has increased by 7,000% since first assuming public office; he’s retaliated against conservative whistleblowers; he’s supported the January 6 insurrection; he was indicted on felonies security charges. In many ways, Paxton is a Democratic campaign consultant’s dream because you can test all of your different attacks.”

Indeed, not every Republican is willing to turn a blind eye to Paxton’s transgressions. Nathaniel Moran, a congressman who represents Texas’s first district, has never previously endorsed in a primary, but decided to back Cornyn.

He said by phone: “I hear so many people on the election campaign trail say, ‘Hey, we’re tired of the corruption in Washington DC,’ and I completely agree with them. So why would we elect a man to the United States Senate who has proven himself to be corrupt and not been contrite about the corruption and not work to change the corruption over the last decade?”

Perry Stagl, 51, sitting behind the counter of his sports memorabilia store in McKinney, shared that skepticism. “It’s definitely not going to be Paxton,” he said. “There’s too many scandals behind him, and now he’s trying to sue everybody. It’s not the American or Texas way. It’s the shadiness of it.”

With policy differences negligible, the primary runoff has descended into a dark battle over culture-war grievances, with Paxton aggressively pushing a narrative regarding the “Islamification” of Texas.

The epicentre of this manufactured panic is a proposed mixed-use development known as Epic City, which is spearheaded by Muslim developers. Paxton has weaponised the justice system to target the development, filing lawsuits and whipping up grassroots hysteria over the creeping threat of “sharia law”.

Last week, on the Senate floor, Cornyn introduced the Ban Outsiders Openly Touting (Boot) Sharia Law Act, which would bar non-US citizens who support sharia law from entering or remaining in the country.

Taylor of UT San Antonio, said: “I’m truly mind-blown by this one, that somehow 25 years after the 9/11 attacks, when a not-so-competent president but nonetheless a Texan pushed the idea of some level of understanding when it comes to Islam, we’re now back to this: ‘Ooh, sharia law, it’s coming for us, we gotta stop all this stuff.’’”

Evan Hunt, Democratic nominee for Texas’s third congressional district, views the strategy as a cynical distraction. He said: “They learned a lesson from Trump that they could get elected if they scapegoat whole groups of people and blame them for all the problems.

“They’re blaming the Hindu American community with claims of H-1B visa fraud. They’re blaming the Muslim community with claims that they’re trying to spread sharia law and take over the country. They’re blaming the Chinese American community, saying that Chinese nationals are trying to buy up property and they want to spy. All of this is nonsense.”

While Republicans trade cultural grievances, voters are suffocating under the weight of an affordability crisis that could define the general election in November, not least among Latino voters who backed Trump in 2024 but could return to the Democratic fold.

Ramirez of Ascend Strategy Labs said: “Someone came to my house today that was a construction worker and was like, Cristina, have you seen how much gas is? It’s $4.20 a gallon. People are struggling to get by. There is a significant portion of the Latino vote that is simply up for grabs. And their number one issue is their deep economic pain.”

Maria Garcia, president of the Hispanic Republican Club of North Texas and a Paxton supporter, said: “I am very concerned that Texas will turn purple. The candidates are just the icing on the top that will help guide them but it’s more because the party has not done a good job. We’re missing leadership. We need better leadership and we need better outreach and messaging.”

For election after election, Democrats and the national media have engaged in the ritual of predicting that demographic shifts will finally turn Texas blue, only to watch the Republican firewall hold firm on election night.

But some say 2026 feels different, largely due to the unique convergence of Paxton’s monumental vulnerabilities, Trump’s historic unpopularity and the emergence of Talarico as a rare talent. The Presbyterian seminarian and former middle school teacher speaks a language of faith that Democrats typically abandon to the right – and could provide a devastating contrast to Paxton’s ethical swamp.

Kendall Scudder, chairman of the Texas Democratic party, said: “It’s sad, the state of things right now. It doesn’t have to be this way. We can get people like this out and put people that are looking out for Texas and who have integrity back in office again. Democrats built this state and it’s going to take Democrats to save it.”

Republicans are quietly panicking. Last month a Texas Public Opinion Research survey showed Talarico ahead of both Cornyn and Paxton in hypothetical matchups. The party will now be forced to spend millions of dollars to defend the Texas seat, draining resources from battleground states.

Katie Gassensmith, a 45-year-old teacher from Allen, Texas, represents the kind of voter who could decide the election. Her verdict on the Republican primary was swift and brutal. “They are both dicks,” she said of Cornyn and Paxton.

“Ken Paxton has no moral values. He has embezzled money from the people and citizens of Texas. He has cheated on his wife. He has misused taxpayer funds. John Cornyn also doesn’t represent me or my politics and beliefs. Both of these gentlemen are out for themselves and their own personal benefit.”

Gassensmith is backing Talarico, hoping that the tide is finally turning. She points to recent local elections where rightwing, book-banning school board members and a Maga mayoral candidate were routed by moderates. She added: “I feel like, hopefully, change is afoot.”