Gates got 59% of the early vote to 41% for Democrat Eliz Markowitz in the suburban Houston district.
The two are competing to replace former Rep. John Zerwas, R-Richmond, in an overtime round that has drawn massive attention from Democrats hoping to build momentum as they seek to flip the Texas House in November. A victory by Markowitz, a Katy educator, would bring them within eight seats of the majority.
Even before Zerwas stepped down, Democrats were eying the seat as a pickup opportunity. He won reelection in 2018 by 8 percentage points, while Beto O'Rourke came within 3 points of carrying the Fort Bend County district.
Democrats went all in. At least three presidential candidates got involved, national and state groups poured hundreds of thousands of dollars into the race and O'Rourke made it his top political priority since ending his White House bid in November.
Gates, a businessman who has unsuccessfully sought office several times before, loaned himself over $1.5 million while weathering attacks stemming from a 2000 child-abuse case. He had the support of Gov. Greg Abbott once he advanced to the runoff, and other statewide officials jumped in as early voting began last week.
Markowitz and Gates were the top two finishers in the November special election, earning 39% and 28%, respectively. Markowitz was the sole Democratic candidate, while Gates faced five other Republicans.
The winner of the runoff will finish Zerwas' term, which goes until January. Both Gates and Markowitz are also running for the full term that begins next year and will appear on the March 3 primary ballot. Markowitz is unopposed, while Gates faces minimal competition.
There were two other special election runoffs Tuesday to fill state House seats, both in much safer territories for Democrats. In House District 100, Democrats Lorraine Birabil and James Armstrong were competing to replace former Rep. Eric Johnson, D-Dallas, who gave up the seat last year after he became the city's mayor. In House District 148, Democrat Anna Eastman and Republican Luis LaRotta were vying to complete the term of former Rep. Jessica Farrar, D-Houston, who resigned several months ago.
Both Birabil and Eastman had massive leads in early voting, getting 68% and 67% of the vote, respectively.
While HD-28 overshadowed the two other runoffs, they did feature interesting storylines. Birabil, a former Democratic staffer, had a rare endorsement by O'Rourke in an intraparty race, while Armstrong, a pastor, received significant funding from Texans for Lawsuit Reform, the influential tort reform group that is better known for supporting Republicans.
Eastman, a former Houston school board member, was working to consolidate her party's support after facing 11 other Democrats in the first round, some of whom now await her in the March primary for the full term. LaRotta, meanwhile, had Abbott's endorsement and was hoping to pull off an upset in the solidly Democratic district.