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The political parties are running an early test of the state’s changing politics in Fort Bend County right now, trying to find out if the purpling trends of 2018 are persistent enough to elect a Democrat in what has been a reliably Republican Texas House district.

State Rep. John Zerwas, R-Richmond, won by more than 8 percentage points in 2018, significantly outperforming some of his fellow Republicans on the ballot that year. At the same time, Republican U.S. Sen. Ted Cruz beat Democrat Beto O’Rourke in the district by just over 3 percentage points.

Two years earlier, Zerwas was unopposed, and Donald Trump, at the top of the ballot, beat Hillary Clinton by 10 percentage points in the district.

House District 28 has belonged to the Republicans for a while now. But that district is a subset of Fort Bend County, a once-Republican stronghold that has turned Democratic.

While Trump won in HD-28 — and this is where a lot of the current Democratic enthusiasm found its root — Clinton won by a healthy margin in greater Fort Bend County. Other Republicans outperformed the president that year, but not by enough to make their Fort Bend results comfortable.

Like Trump in 2016, Cruz in 2018 won in Zerwas’ district but lost countywide, coming in with 43.6% of the vote to O’Rourke’s 55.8%.

That brings us to the special election underway right now. Zerwas, an anesthesiologist in real life, gave up his perch as chairman of the House Appropriations Committee earlier this year to become executive vice chancellor for health affairs at The University of Texas System.

The race to fill the rest of his term is underway, with early voting about to end and the election set for next Tuesday. Republican Gary Gates is trying to keep the seat in the GOP column; Democrat Eliz Markowitz is trying to wrest it away.

She’s getting a lot of help from big Democratic names, starting with O’Rourke, who has spent significant time on the ground in HD-28, knocking on doors, talking to voters and volunteers and helping Markowitz pull this off. Joe Biden endorsed her, as did Michael Bloomberg and Elizabeth Warren. Julián Castro has campaigned in the district.

In real ways, the contest has little to do with who’s in the Texas House; after all, the winner will only serve until the first of next year, and the Legislature doesn’t meet this year. It’s not like they’re fighting over power.

This is about politics, and about the two major parties’ ability to turn out voters and to win a debate in a red district in a blue county. Democrats hope to build on the 2018 wave, to prove that things really are going their way in suburban Texas and that the 2018 election results weren’t a fluke borne of a controversial mid-term president and an overheated race for U.S. Senate.

Markowitz and Gates will have to keep campaigning, no matter who wins next week. The full term that starts in a year, when the Legislature meets, is on the 2020 ballot. Early voting in the March primaries starts next month; Markowitz will be unopposed there, but Gates will face Schell Hammel. The winner of that will face Markowitz in November.

That’ll be a chance for someone to get even.

What’s on the line now is partly bragging rights, partly fine-tuning in advance of the primary and general elections. Based on its recent history, the district belongs to the Republicans. But Zerwas out-performed the people above him on the ballot, and Gates lost a number of other races on the way to this one. Without an incumbent in the race, Democrats hope to extend the blue trend sweeping across the rest of the county to this seat.

Republicans hope the opposite. The 2020 elections are full of seats in other parts of the state where Democrats came much closer to winning in 2018. They’ve got a full plate without adding HD-28 to it.

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