When Tom Perez, the chairman of the Democratic National Committee, visited Austin this past weekend for the state party's annual fundraiser, there was no race he mentioned more than the special election for House District 28, a suburban Houston seat vacated by Republican state Rep. John Zerwas last month.

It was among the first topics Perez mentioned in a pre-dinner gaggle with reporters. And once he took the stage later in the night, he brought it up four times, twice urging donations for the sole Democratic candidate, Eliz Markowitz, who sat at the table closest to the stage.

"This ain't Tom DeLay's Fort Bend County anymore," Perez said, touting the politically changing terrain on which the Nov. 5 contest is unfolding. He reveled in the relation to the former House GOP leader, later telling Markowitz: "You are a remarkable role model — in Tom DeLay's county. I love saying that."

The race's top billing at the dinner was no accident. Democrats both inside and outside Texas have become intent on flipping HD-28 as they charge toward 2020 with hopes of capturing the lower-chamber majority. For Democrats, a win in HD-28 would not only serve as a momentum boost heading into next year — potentially bringing them within eight seats of the majority — but provide a gauge of just how many seats are really in play.

"We think we're gonna take back the state House," said Abhi Rahman, a spokesman for the Texas Democratic Party. "This will be a good barometer of how big the wave is."

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The GOP has been defiant in the face of the Democratic push to take HD-28. In a recent email to local Republicans, county party chairwoman Linda Howell said the district "is our Alamo and we will defend it."

"I don't think a Democrat is going to capture House District 28 — it's just not gonna happen," one of the Republican candidates, Tricia Krenek, said in an interview. "We're working hard every single day. Our voters are energized. They are clearly aware of what's at stake and they are committed to keeping House District 28 red."

To be sure, Democrats were already targeting HD-28 before Zerwas, who now works for the University of Texas System, announced in late July that he would resign at the end of September. The former chairman of the powerful House Appropriations Committee won reelection last year by 8 percentage points, while U.S. Sen. Ted Cruz carried the district by only 3 points.

In an early boon for Democrats, Markowitz was the only candidate from the party who filed for the special election, ensuring that their vote would not be split and making it likely that she would advance to a likely runoff with a Republican. Six GOP candidates, meanwhile, lined up for the seat, and three have emerged as serious contenders: Anna Allred, a Houston anesthesiologist from the same doctor group that Zerwas is from; Gary Gates, a wealthy businessman and perennial candidate from Rosenberg; and Krenek, a former member of the Fulshear City Council.

Their viability was confirmed by the first fundraising reports in the race, which were due Monday and showed Allred, Gates and Krenek were the only GOP contenders with significant financial activity. Powered by big donations from medical groups, Allred raised more than any other candidate — $159,000 — while Gates spent the most — $214,000 — after almost entirely funding his campaigns with $271,000 in loans to himself. Krenek, for her part, also loaned herself six figures — $150,000 — and ended the period with the highest cash on hand, $113,000.

Markowitz, meanwhile, raised $62,000, spent $16,000 and has $38,000 cash on hand after getting a $15,000 loan. She had a far higher number of contributions than any Republican in the race, and in a sign of the race's statewide importance, her donor list included at least 10 Democratic members of the Legislature.

The all-hands-on-deck effort will continue this weekend, when state Rep. Celia Israel, the new chairwoman of the House Democratic Campaign Committee, headlines a Katy fundraiser for Markowitz whose hosts include 17 other state representatives. Israel, of Austin, is also making plans to have members visit the district the weekend before Election Day to block walk for Markowitz.

"This is our most, most focused effort," Israel said at the state party dinner, adding in a statement for this story that the HDCC is "all in" for Markowitz and will "leave it all on the field."

Markowitz has also gotten the attention of national Democrats beyond Perez. The Democratic Legislative Campaign Committee has named her one of its "Spotlight Candidates," and Democratic presidential candidate Beto O'Rourke went door-knocking with her last month before joining her for a rally in Katy.

"Beto won 48.1% of the vote here," Markowitz said in an interview after the rally. "And at the rate of expansion and ... demographics shifts are coming in, I totally believe we can get over 2% to make that flip happen, especially if we motivate our voters and make sure they come out and vote."

Markowitz, a Katy educator who unsuccessfully ran for the State Board of Education last year, is focusing her campaign on improving public education and expanding access to health care. The Republicans, meanwhile, are also talking about education, as well as building on the property tax reforms that the Legislature passed earlier this year. Some of the GOP contenders, likely aware they still have to consolidate support from their own party, are also highlighting issues with a more partisan hue such as securing the border and protecting gun rights.

Krenek, who boasts a local endorsement list with over 50 names, is leaning on her community involvement in Fort Bend County, where she works as an attorney and served from 2014-2018 on the Fulshear City Council. Of all the candidates, she said, she has "the strongest record of service and results in the community ... the deepest community ties, and I would say I am the grassroots candidate in this race."

Gates is a known quantity in Texas politics after having unsuccessfully run for several offices over the years, most recently railroad commissioner in 2016. This time, though, he said he is doing more personal outreach to voters than he ever has, aiming to knock on 150 doors a day and already hitting well over 5,000.

"What’s made me successful in business and in every endeavor — you learn more from your failures even more than your successes," said Gates, who is running on his extensive business credentials like in past campaigns. "I have learned that I have never really gone out and engaged voters in the way that I am right now."

Allred, meanwhile, is campaigning as a political outsider who is best positioned to go the distance in the battleground district. It could see as many as five elections through 2020: the special election, a special election runoff, the primary, a primary runoff and the general election.

"Three of my opponents have all run and lost, one of whom has lost half a dozen times," Allred said in a recent news release. "I’m in this campaign to win."

The HD-28 special election is not the only contest on Nov. 5 to fill a state House seat. There are two others — to replace former Reps. Jessica Farrar, D-Houston, and Eric Johnson, D-Dallas — though they are happening in far less competitive territory and unlikely to change party control.

Early voting begins Oct. 21 for all three special elections.

Disclosure: The University of Texas System has been a financial supporter of The Texas Tribune, a nonprofit, nonpartisan news organization that is funded in part by donations from members, foundations and corporate sponsors. Financial supporters play no role in the Tribune's journalism. Find a complete list of them here.