Last week, the Republican State Leadership Committee, a national group focused on state legislative races, endorsed Jetton and Berry and announced it would help them as part of a $200,000 investment across five Texas House runoffs.
In another Austin-area House seat, Berry and Austin attorney Jennifer Fleck are facing off for their partys nomination to take on Goodwin.
Abbott endorsed Jetton in the run-up to the March primary and Miller got behind Morgan, a Richmond insurance agent, four days later.
Despite Abbotts involvement, Morgan almost won outright in the three-way primary, getting 49.7% of the vote to 40.7% for Jetton.
Should I win this runoff, Im obviously a different person than Rick Miller, Morgan said.