SAN ANTONIO — For as long as María Rodríguez can remember, the South Side of San Antonio has just about always elected Democrats, Hispanics like herself who emphasized improving public education and access to health care.
But last week, as she walked out of an early polling site where she had cast a ballot in a tightly contested runoff for an open State House seat, Ms. Rodríguez, 55, wondered whether her once solidly Democratic district might flip.
This time, there was a strong chance that the Republican candidate, a Latino who briefly held the seat in 2016 and received the most votes in last month’s five-way special election, could emerge the victor and represent Ms. Rodríguez and about 160,000 of her mostly Latino neighbors.
“I’m nervous,” she said.
The contest for the vacant seat in the 118th District has exposed the vulnerabilities of a traditionally Democratic stronghold, as Republicans make an all-out effort to gain ground with Latino voters in South Texas. It also has tested the progress of a Republican Party that has openly courted those voters, who have cited a range of grievances, from rising crime and faltering infrastructure to feeling abandoned by Democrats.
None of the three Democrats and two Republicans who ran in the special election received a majority of votes, leaving voters with one candidate from each party — both Latinos who were raised in the district. Early voting began last week, and Election Day is on Nov. 2.
The Republican candidate, John Lujan, a 59-year-old retired firefighter and former sheriff’s deputy who now owns an IT firm, has campaigned on a platform of public safety and job creation. His opponent, Frank Ramirez, a 27-year-old former legislative aide, has zeroed in on investments in public education, aging infrastructure and property tax relief.
In the special election, held to replace a Democrat who resigned this year to take a teaching position at a college, Mr. Lujan garnered nearly 42 percent of the vote and Mr. Ramirez captured about 20 percent. The two other Democrats accounted for a combined 30 percent of the 7,075 votes cast. But in the end, a total of 47 more ballots were cast for Republicans — enough to give the G.O.P. a slim edge.
“It’s really anybody’s race,” said Jon Taylor, a political science professor at the University of Texas at San Antonio who has followed the special election closely.
At the three early voting sites across the district, traffic over the past few days has been steady but slow.
Martin Flores, 57, a longtime Republican who voted for Mr. Lujan, said it was time for a Republican to represent a growing conservative swath of Texas. The issues driving him, he said, are rising taxes and a spike in deadly crime that has plagued major cities. (Homicides were up in San Antonio last year, but overall crime was not.)
“I’m confident that every decision he makes,” Mr. Flores said of Mr. Lujan, “he’s going to listen to the people.”
Diana Espinoza, who is in her 40s and works in human resources, said she recently had a short and pleasant conversation with Mr. Lujan but was not convinced to vote for him. As the mother of a sixth grader, she said she was most concerned in this contest with increasing access to technology at local schools. She worries that a Republican will have different priorities. She also recognizes that Democrats have largely been stymied at the State Capitol by a Republican majority.
A victory by Mr. Ramirez, she said, could help usher in an era of a long-promised blue wave in an increasingly ethnically diverse state.
“I want the Democrat to win,” Ms. Espinoza said. “But if Lujan wins, then I want him to do a good job for us. It shouldn’t matter what party you are from.”
With this seat critical to the Republican Party’s efforts to make inroads in South Texas, Mr. Lujan has the financial backing of the state’s Republican establishment, including Gov. Greg Abbott and a top lawmaker. Through late October, Mr. Lujan had raised more than $500,000 in direct and in-kind donations, according to filings with the Texas Ethics Commission. Mr. Ramirez missed the deadline on Monday to file his campaign report, but through September had raised $60,000.
The district, which includes communities along the fast-growing corridors of Interstates 35, 37 and part of Loop 410, a highway that encircles the city, is about 70 percent Hispanic. It is composed of working-class families, with about a quarter of households making between $25,000 and $50,000 annually and nearly 15 percent of adults having earned a bachelor’s degree or higher, according to a state district profile.
Historically, voters in the district have tilted left. In the 2020 election, 56 percent voted for President Biden, while 42 percent supported Donald J. Trump. (Mr. Biden captured 58 percent of the vote in Bexar County, which includes San Antonio.)
But today, Democrats are increasingly alarmed at what appears to be waning support among Latino voters, once a reliable constituency. In recent polls, Mr. Biden’s overall approval rating was in the low-to-mid-40s, and about 50 percent among Latino voters.
In South Texas, where there have been some signs that the Republican Party is making headway with the Latino population, conservative operatives said they wanted to see the national polling numbers translate into votes for their candidates. And San Antonio — a majority Hispanic city — has long been seen as the gateway to the rest of the region.
Indeed, farther south in the Rio Grande Valley, along the state’s border with Mexico, Republicans have made some progress. Although Mr. Biden won Hidalgo County, which includes McAllen, by 17 percentage points last year, it was a considerably closer contest than Hillary Clinton’s 40-point victory. In nearby Zapata County, Mr. Trump won by five points.
The decline among progressives in majority Latino enclaves has pushed the G.O.P. to expand its base beyond an overwhelmingly white political coalition, buoying them to challenge Democrats on their turf. The Republican National Committee now runs offices in San Antonio, McAllen and Laredo, another border city, to court more Latino voters.
“Republicans are doing a much better job at outreaching to Latinos,” said Sharon Navarro, a political science professor at the University of Texas at San Antonio.
Outside an early polling site last week, Mr. Lujan said he appreciated the task and was up for it. He had been here before, having won a special election for the same seat in January 2016 only to lose it in a general election later that year. “The trick is holding it,” he said.
Mr. Lujan, the son of a minister and public school principal, said he had focused on issues that San Antonio residents cared about, like border security and promoting small businesses. He often touts the IT consulting firm he founded with a handful of employees in 1999. Today it employs more than 400, he said. As the father of three adopted sons, he also has focused on strengthening the state’s foster care system.
Across the district, Mr. Ramirez said the challenge he faced pushed him to keep knocking on doors. As many residents commented on how young he looked, he reminded them that he had immersed himself in government work since graduating from the University of Texas at Austin in 2016. He had served as a legislative director and chief of staff in the 118th District and, more recently, as a zoning and planning director for a San Antonio councilwoman, a role he left in August to run for office.
On Monday afternoon, Emmanuel Alvarez, 21, took his 65-year-old mother, Maria Jasso, a retired factory worker, to a polling site to pick up campaign pamphlets on each candidate.
They had not made up their minds, though Ms. Jasso, who said improving access to health care and fixing cracked roads across much of her neighborhood were top of mind, was leaning toward Mr. Ramirez. Her son, on the other hand, said it might come down to personality. So far, he has agreed with both candidates and their platforms.
“Both have good ideas,” he said. “I’m not liberal or conservative. I fall in the middle.” The question, he said, was whether to cast a ballot for the less experienced politician or someone who had already served once before but could align himself with the state’s Republican majority.
“I don’t know yet,” Mr. Alvarez said. “Let’s see who convinces me before Tuesday.”
J. David Goodman contributed reporting from Houston. Kitty Bennett contributed research.