It was a border-town stop for Beto O’Rourke’s Senate campaign, but another Democratic politician commanded particular attention: Gina Ortiz Jones, a history-making congressional candidate — gay, Filipina-American, an Iraq War veteran — hoping to turn a majority-Hispanic district blue. “Really special person,” O’Rourke said, as Jones stood and waved.

But soon, a county chairwoman posed an uncomfortable question. O’Rourke had not endorsed Jones. In fact, he had elevated her Republican opponent, Rep. Will Hurd, with frequent praise and, most memorably, a livestreamed bipartisan road trip that helped jump-start their midterm campaigns. Would O’Rourke support the Democrat?

“This is a place where my politics and my job and my commitment to this country come into conflict,” O’Rourke said. “I’m going to put country over party.”

Some supporters of Jones saw it differently: Beto O’Rourke was once again putting Beto O’Rourke first.

Five months later, as O’Rourke considers a run for president, his decision not to back Jones lays bare the go-it-alone streak that has defined his career, separating him from a modern Democratic Party that has prized near-uniform opposition to Republicans in Washington. While supporters view his above-the-fray message as the foundation of his appeal, he has left important Democratic constituencies wondering if he can be fully trusted as an ally.

“Beto-first politics,” said Jess Morales Rocketto, a Democratic operative who worked for Hillary Clinton in 2016. “He was concerned about Beto. I’m not sure he was concerned about building the future of Democratic politics.”

In Texas’ 23rd Congressional District, his choice was more than symbolic. Hurd won by fewer than 1,000 votes, and many voters and local activists hold O’Rourke — whose success helped lift down-ballot candidates across the state — largely responsible for Jones’ defeat.

“All I kept thinking was, wait, Beto is supposed to be helping us because he’s a Democrat,” said Rosey R. Abuabara, leader of TX-23 Indivisible, which worked to oust Hurd. “I really felt like Beto was just getting in my way.”

O’Rourke’s aides noted that his campaign — and its sprawling grassroots operation — had been enormously helpful to the party’s cause, sharing voter information with fellow Democrats, opening hundreds of campaign offices and inviting other candidates to speak at his well-attended events.

“Beto fully invested in building the future of Democratic politics across Texas,” his spokesman, Chris Evans, said in an email, adding that the campaign’s efforts would serve as a foundation “for all future Democratic campaigns in the state.”

Yet even some admirers of O’Rourke have struggled to reconcile the snub of Jones, particularly in a year when female and nonwhite candidates like her helped lift Democrats to a House majority. Though O’Rourke stayed neutral, Jones drew high-wattage help in the race, including from prominent Texas Democrats like Julián Castro, the former housing secretary who is running for president, and Wendy Davis, the former candidate for governor and abortion-rights activist.

Asked if O’Rourke had a special responsibility to support a female candidate of color in this Democratic moment, Davis sounded almost anguished.

“It’s really hard to say,” she said, adding that she did not mean to “back-seat drive” a friend’s decision-making. “I would feel that special duty. I personally would feel that. Beto’s not me, and I’m not Beto.”

O’Rourke’s very presence as a would-be presidential contender for 2020 is an issue of heated debate within the party. He is a prolific fundraiser who proved he can energize younger voters, and some early polls place him third behind Joe Biden and Sen. Bernie Sanders, well ahead of many more decorated politicians. But he is also a relatively inexperienced lawmaker who lost his Senate race against Ted Cruz.

For close watchers of O’Rourke’s rise, his approach to Jones’ contest captured the twin pillars of his political worldview: He has an instinct for performative campaigning, reaching for multiplatform connection to voters but often lurching toward extreme oversharing. (O’Rourke was widely mocked recently after turning the camera on his own dental appointment.)

And he has often defied the wishes of his fellow Democrats, especially traditional party leaders, who have eyed him warily since he challenged a Democratic incumbent in 2012 to reach Congress in the first place.

Through a fluke of weather, timing and internet trendsetting, Hurd sits at the intersection of it all. Until March 2017, he and O’Rourke had been friendly enough as district neighbors, but never especially close. Then, after a snowstorm grounded their flights from Texas to Washington, O’Rourke suggested they drive instead — and record themselves for all 1,600 miles, answering questions from followers along the way.

Alone in their rented Chevy Impala, they sang along to Willie Nelson, hashed out health care and trade policy and made a late-night doughnut run in Tennessee, attracting hundreds of thousands of viewers and wide-scale media coverage. Newt Gingrich called in to salute them. Mark Zuckerberg chimed in approvingly on Facebook.

“Our party leadership is probably not super excited that we’re doing this,” O’Rourke said at one point.

He was half right. Democrats in Washington, who had eyed Hurd’s seat as a prime pickup opportunity after Clinton carried the district in 2016, winced at the sight of O’Rourke bolstering Hurd’s reputation for bipartisanship. Republicans were delighted to have a high-profile showcase for Hurd’s personality and moderate image.

His congenial political brand helped him establish a consistent lead over Jones in private polling, giving pause to some national groups, like the Democratic Congressional Campaign Committee, about investing in the race.

“It was a huge boost for us,” Matt Gorman, communications director for the National Republican Congressional Committee during the midterms, said of the road trip. “That thing went totally viral.”

Mark McKinnon, a veteran of Texas politics who was an adviser to George W. Bush, said by email that the road trip became a “life preserver for Hurd and launchpad for Beto.”

O’Rourke and his team seemed to recognize this. The ride registered as his campaign’s unofficial kickoff. And he was quick to invoke his relationship with Hurd, to deflect attacks from Cruz that he was too far left for Texas, and to burnish his self-styled standing as a high-minded antidote to the Capitol’s seemingly intransigent partisanship.

“I know how disappointing it is to people,” O’Rourke said in an interview last summer, explaining his decision not to support Jones. “It’s disappointing for very legitimate, really important reasons. Like, I also want to be in the majority.” He added that Jones would make an excellent congresswoman if elected.

Party officials and activists kept up the pressure, cornering him at rallies and fundraisers, including one in San Antonio where O’Rourke raised his right hand in a mock ceremony and pledged not to make Hurd “look cool” even as he refused to oppose him.

“Basically I told him he needed to dance with who brung him,” said Mary Bell Lockhart, chairwoman of the Brewster County Democratic Party. “And it was primarily Democrats.”

O’Rourke’s supporters insist he can be counted on to pursue Democratic priorities, while noting that his relationship with Hurd allowed the two to collaborate on shared causes like border policy. (Hurd has been a rare Republican opposing the construction of a wall.)

But O’Rourke’s history with the party is more complicated than it appeared in a binary race against Cruz, whom Democrats could generally agree to loathe. He was known in Washington for declining to pay dues to the Democratic Congressional Campaign Committee. In 2016, he voted against Nancy Pelosi to lead the Democratic caucus, supporting Tim Ryan, a centrist from Ohio.

“We are all products of our environment,” said Pete Gallego, a former Democratic congressman who lost his seat to Hurd in 2014. “He has found tremendous success by shaking things up and by not being part of the party apparatus.”

After Jones won the Democratic nomination for the seat, she and O’Rourke had a cordial conversation by telephone. O’Rourke neither pledged to help Jones nor told her directly that he would be withholding his support, according to people briefed on the call.

In late June, Ronald Smith, a liberal activist in Hurd’s district, emailed O’Rourke’s campaign demanding to know: “Has Beto endorsed Gina Ortiz Jones? If not, when will he endorse her?” Smith said he wanted “a team player for my next Democratic senator.”

An O’Rourke campaign representative offered a noncommittal reply in an email reviewed by The New York Times: “We are evaluating some local and regional races at this time.”

By the summer, aides to O’Rourke had made clear to Jones’ campaign that he would not support her candidacy, three Democrats familiar with the exchange said. O’Rourke valued his relationship with Hurd and was mentioning it frequently on the campaign trail, as he sought to win crossover support from right-of-center voters.

Jones, who has said she is likely to run again in 2020, declined through an aide to be interviewed about O’Rourke.

O’Rourke’s defenders note that several Democrats benefited from his stronger-than-expected showing against Cruz, helping the party flip congressional seats in the Houston and Dallas areas.

But in no other swing district was O’Rourke’s allegiance in question. O’Rourke carried the 23rd District even as Hurd narrowly won re-election there. In the section of the district that spills into Bexar County, home to San Antonio, O’Rourke outperformed Cruz by about 3,900 votes, a review of precinct-level election results found. The same set of precincts voted for Hurd over Jones by nearly 4,700 votes. Hurd won the district by just over 900 votes.

“We know exactly what the Beto bump was and it was amazing,” said Smith, the liberal activist. “But my assessment was, for Democrats, as well as we did this last election cycle, we would have had one more seat if Beto had been on board with Gina Ortiz Jones.”