She had all ingredients needed to be the next Democratic star: young, populist, with the credibility to speak for an important constituency - Hispanic Americans.
On the campaign trail, Jessica Cisneros painted a picture of herself as a child of South Texas, from growing up in a poor, Spanish-speaking household to becoming a lawyer.
Addressing a crowd of hundreds hiding in a church gymnasium from a blistering Texas sun, she made her pitch to oust a nine-term incumbent Democrat from his seat in Congress representing the border district that is over three-quarters Latino.
The centrist Congressman Henry Cuellar - for whom she used to intern in Washington DC- was "anti-labour, anti-immigrant, [and]anti-choice," Ms Cisneros told supporters.
It appears that message failed to resonate with an important swathe of voters in Texas' 28th Congressional District, which stretches from the eastern suburbs of San Antonio south to the Mexican border.
Following a recount, Mr Cuellar was declared the winner in the primary contest to determine the Democratic candidate in November's general election.
He managed to edge past Ms Cisneros by the narrow margin of just 289 votes.
In a series of tweets after the results were declared on 21 June, Ms Cisneros said that her campaign "always knew this was an uphill battle" against the Democratic Party establishment.
"We still refused to back down," she added. "The biggest thing holding us back from pursuing the change we deserve is their fear. Fear of change, fear of the future."
Mr Cuellar - who had twice declared victory already - said he welcomed the result and that it is "time to come together and win the general election in November".
The nail-biter of a race laid bare the tensions and divisions within the Democratic Party and, according to some, exposed the weakness of their political calculus - a belief that abortion, free college and "social justice" issues will drive people to the polls.
In some ways, it was always clear that Ms Cisneros would have an uphill battle to fight.
Though she had the backing of left-wing icons Alexandria Ocasio-Cortez and Elizabeth Warren, she struggled to garner the local support and endorsements needed to unseat a long-time incumbent.
At an appearance in San Antonio, Texas, for Planned Parenthood a week before the vote in May - abortion access was a key part of her campaign platform - few had even heard of her.
Ahead of the vote, Bernie Sanders, the popular left-wing senator, flew down to stump for her. But attendees at her rally seemed more enthusiastic about seeing him than her. Many were not even from her district, and it was the senator who was given top billing.
On the same day farther south in Laredo, an unassuming town on the southern-most tip of the Lone Star state, Mr Cuellar stood on a pavement outside a firehouse,greeting voters who were casting their ballots early, chatting in Spanish and English.
Speaking to the BBC in between selfies and handshakes, Mr Cuellar expressed confidence that he would win at the polls.
It is "bread and butter" issues like infrastructure, border security and jobs that voters care about, he said.
That he is one of the few Democrats who are anti-abortion - a stance that's increasingly regarded as radioactive within today's wider party - hardly figured.
Of the left-wing challenge he faced, he said: "I thank Bernie Sanders and Elizabeth Warren for making the trip and spending a little bit of money in Texas. But at the end of the day, it's going to be the voters that make the decision."
Indeed, the Cisneros camp probably "overestimated the enthusiasm" that issues like abortion choice could attract among a largely Catholic constituency, said Sergio Mora, the former Democratic Party Chair of Webb County, which includes Laredo, the political heart of the district.
"It's socially conservative, and the church is important," he said. "A lot of voters skew older, and many of them are pro-life to begin with."
Standing at the counter of her crafts store, covered wall-to-wall with crucifixes and statues of the Virgin of Guadalupe, Angelica Garza, 75, said of Ms Cisneros: "I don't wish her ill, but I would never vote for her. Ever. Mr Cuellar is a good person. I always vote for him."
Ms Cisnero's stance on abortion is the reason. "If she was the candidate (for Congress) I won't vote. I always vote; but I wouldn't. I cannot. It is my belief," said Mrs Garza.
"This is a Catholic city and we don't believe in that."
But abortion is clearly shaping up to be a key voting issue in November's national midterm elections that will determine control of Congress.
In May, a leaked Supreme Court document suggested that the high court will rule to overturn the landmark 1973 Roe v Wade case affirming a constitutional right to abortion.
It has left open the possibility that individual states will be able to ban abortions. Democrats running for office up and down the US have vowed to make protecting abortion access a key part of their platform, Ms Cisneros among them.
"I truly believe abortion is healthcare," she told BBC.
Her campaign described Mr Cuellar as "the last pro-life Democrat in Congress". Following the Supreme Court leak, the congressman - a practising Catholic - stated that he has "always been pro-life", but is against an outright ban. He said exceptions should be made in cases of rape, incest or medical danger.
"My faith is clear: abortion must be rare and safe," he said.
The issue is one that divides the Latino voters who make up the bulk of the Democrats' constituents in South Texas. While district-specific figures are not available, 2018 data from the Public Religion Research Institute found that more than half of Texas Latinos - 53% - believe that abortions should be illegal in most cases.
A 2021 Gallup poll found that low-income voters were more likely to be "pro-life", a factor which may come into play in a district where a fifth of residents are under the poverty line and less than 20% have graduated from college.
For about two weeks the vote was too close to call, before officials from the Texas Democratic Party certified the ballots, putting Mr Cuellar ahead by 281 votes.
A recount requested by Ms Cisneros did little to change the outcome and instead increased Mr Cuellar's lead by eight votes.
In Laredo, some voters said that a Cisneros win would have meant that they would eventually turn their backs on the Democrats altogether.
Ms Cisnero's pro-choice stance is symptomatic of being "way too far left for South Texas", said one voter, a law enforcement officer who did not want to be named.
"I eventually want someone besides Cuellar, but it's not going to be her," he said. "I'd probably vote for the Republicans then, even if I don't like it."
This story was updated on 22 June.