The unique unlikability of Ted Cruz was, for a time, an asset in deep-red Texas. Elected to the Senate in 2012 on a wave of Tea Party discontent, Cruz quickly established his outsider credentials by shutting down the government, grandstanding, maligning his colleagues, blithely stoking ignorance and generally making himself the most hated man in the Senate. “If you killed Ted Cruz on the floor of the Senate, and the trial was in the Senate, nobody would convict you,” Lindsey Graham said in 2016, only half joking. Conservative hardliners loved it, right up until they discovered an even more unpleasant avatar of populist outrage in Donald Trump.

Since then, Cruz’s once unavoidable presence on the national stage has been diminished. And political strategists in Texas are now beginning to credibly wonder if Cruz, whose abrasive posturing made him a 2016 presidential front-runner, may be truly vulnerable in his re-election bid this November. Cruz is facing a formidable challenger in Beto O’Rourke, a charismatic congressman from El Paso with the best shot in a generation at turning Texas blue. O’Rourke, who is all but assured to secure the Democratic nomination when Texas voters cast their primary ballots Tuesday, remains a relative unknown. But he has far higher approval ratings than both Cruz and Trump, whose negative favorability is hanging over the race. In the state, battle-tested political insiders are now conceding his chances as at least a legit contender. “With Ted Cruz, familiarity breeds contempt. It continues to be true that no statewide elected official is more disliked and less popular than Cruz,” one longtime Democratic strategist in Texas told me. “Surely that truth is a part of Beto’s successful dynamic thus far.” Harold Cook, a veteran Democratic operative in the state put it more succinctly: “He is the first Republican, maybe, in a long time that has to go around one of the biggest states with the most media markets on Earth and convince voters that they are wrong about him.”

O’Rourke got another boost this week as early voting numbers rolled in, showing a massive uptick in Democratic turnout. According to the latest data, Democrats outvoted Republicans in Texas’s top 15 counties. In the top 10 counties with the highest number of registered voters, Democratic turnout more than doubled compared to four years ago. “The early voting numbers are pretty incredible,” said a former G.O.P. political operative who now works in the Texas business community. “It definitely shows that Democrats are ready to vote. They’re ready to send a message.”

It would be tough to find a more strikingly different pair than O’Rourke and Cruz. While Cruz has emerged as a paragon of Washington dysfunction, aligned with the obstinance of the Tea Party and House Freedom Caucus, O’Rourke has been extolling bipartisanship. Not reaching across the aisle is a “pretty fucked up way to run a country,” O’Rourke told me last year, after he crisscrossed the country with his fellow Texas congressman, Republican Will Hurd. “I am not a rocket scientist, but the only way you can get something done in D.C. when you have Republican majority control in the House and the Senate is to work with Republicans, so I am going to work with Republicans.”

“[Cruz] just wants to be president, and I don’t think any voter anywhere wants to be a mere prop in somebody else’s play.”

G.O.P. operatives initially dismissed O’Rourke, who has vehemently opposed a border wall, as too liberal for Texas. “We have never seen anybody with his ideology elected in Texas. If elected, he would be one of the most liberal senators in the nation. He would rival Elizabeth Warren,” one longtime Republican operative, speaking on the condition of anonymity, told me last year. But the political climate has shifted dramatically in the last several months, with Democrats running the table in a series of special elections that could presage a wave election in 2018. And O’Rourke has capitalized on the upsurge. In a sprawling state with 23 media markets, where a Senate campaign can cost $30 million, O’Rourke is currently out-fundraising Cruz, taking in $2.3 million in the first quarter of 2018, compared to Cruz’s $803,000. “I never thought I’d point [to] this, but he’s getting pretty good crowd sizes, he’s getting some good coverage, he out-fund-raised Ted Cruz—which are things that are showing enthusiasm,” the former Republican operative told me. “Myself, along with most of the other political class, ignored that stuff in 2016 with Trump, and I think it would be foolish to ignore just because it’s Texas and [O’Rourke] is a little bit further [left of center].”

O'Rourke speaks at a campaign event in Austin on April 1, 2017. By Drew Anthony Smith/Getty Images.

Democratic strategists are trying to temper their optimism. “Even those who don’t like Cruz would have to admit that Ted Cruz is perfectly willing to put in the work,” Cook told me, suggesting Cruz's voracious appetite for kissing small children, leading prayer groups, and devouring market style barbecue in public settings. Internal polling, meanwhile, from Cruz’s campaign shows the incumbent senator ahead by 18 points. And Democrats have been disappointed before, hoping for long-awaited demographic trends, facilitated by the state's large urban populations and transient immigrant landscape, to finally turn the tide. Wendy Davis, the Ivy League-educated, telegenic state senator who ran for governor in 2014, lost by double digits to Greg Abbott. Hillary Clinton, who made a brief, bold play for Texas in 2016, ultimately lost the state by nine points. Still, the national trend is promising. Since Trump took office, the G.O.P. has lost 39 statehouse seats. “I have for years thought that when a Democrat wins statewide in Texas, it was not just that it was going to be a bang-up Democrat,” Cook continued. “It was going to have to be against a national backdrop of an unpopular president in the White House and voters everywhere.”

Cruz, said Cook, is “fighting a headwind of Donald Trump’s unpopularity. He is fighting a headwind of his own previous statements and behavior. He is fighting the headwind of deep suspicions among voters that he has never really wanted to be their United States senator. He just wants to be president, and I don’t think any voter anywhere wants to be a mere prop in somebody else’s play.”