In the little-watched judicial primary between Waco attorney Gina Parker and Texas Court of Criminal Appeals Judge Bert Richardson, the pivotal figure may prove to be Rick Perry.

Texas’ longest-serving governor is back on the state’s political scene in an unlikely place: backing Parker in her race to oust Richardson, who as a trial judge in 2015 refused to dismiss a criminal indictment against Perry. Perry has endorsed Parker, and a new political action committee with significant ties to him is running Facebook ads on her behalf.

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Perry was indicted in 2014 after threatening to veto funds to the Travis County District Attorney’s Office after DA Rosemary Lehmberg was arrested for drunken driving. In 2016, the Court of Criminal Appeals dismissed the final indictment and ended the case, citing concerns about separation of powers and writing that courts could not limit a governor’s ability to veto. Richardson, who was by then on the high court, did not participate.

Of seven Republican incumbents up for reelection this year to the Texas Supreme Court and the Texas Court of Criminal Appeals, Richardson is the only one who has drawn a primary challenger. Parker said she decided to challenge Richardson because she considers him the least conservative of the three incumbents on his court up for reelection this year, and said she did not even realize Richardson had been the judge in the Perry case until she had already decided to challenge him.

Richardson said her reasoning is obvious.

“She’s made my ruling in the Rick Perry matter the center point of her campaign,” Richardson said in an interview. “I’ve read lots of ugly things. I’ve just tried to stay above the fray and keep it a professional race.”

On the campaign trail, Parker has argued Richardson’s work on the Perry case demonstrated poor judgment. Richardson, who stands by his work in the case, said it was not in his power to throw out the indictment the way the high court ultimately did.

“I was acting as a trial court judge, with virtually no authority based on case law and precedent from the Court of Criminal Appeals to dismiss it unless the Court of Criminal Appeals changed the rules. That’s what they did, and they had the right to do that,” he said. But “I ruled as a trial court judge — that was my role.”

In a section of her campaign website called “Distinctions that Matter,” Parker wrote that “my opponent appears to have been influenced by the political pressure brought upon him, and therefore, he failed to make a straightforward decision and uphold the rule of law.”

“This is the biggest difference between me and my opponent. I will make the right legal decision based on the rule of law,” she added.

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The Texas Court of Criminal Appeals, whose nine judges are all Republicans, is the last stop for criminal matters in the state, including death penalty appeals. Statewide judicial campaigns, particularly for this court, tend to be low-information, low-fundraising bids that involve more education than inspiration. One Richardson campaign pamphlet, for example, is devoted almost entirely to explaining the state’s court system. And on Monday, with about a week before the primary, Richardson reported having $41,320.45 on hand — more than five times Parker’s tally of $7,282.28.

Richardson is framing the race around his experience. A former federal prosecutor, he was appointed to the bench in the late 1990s by then-Gov. George W. Bush and has served for decades as a judge. He was elected to the state’s highest court for criminal matters in 2014.

Parker has worked as a prosecutor and criminal defense attorney, and she also owns a dental manufacturing business. She was appointed in 1997 to the Texas Commission of Licensing and Regulation; Perry reappointed her in 2001 and named her presiding officer in 2005. She has never been a judge but described her role at the department, which licenses dozens of professions, as “quasi-judicial” because commissioners also hear contested enforcement action appeals from the State Office of Administrative Hearings.

In the final stretch before Texas’ March 3 primary, Parker has enjoyed an assist from a new PAC with close Perry ties — an unusual development in judicial primaries. As of Tuesday evening, the American Freedom Fund had already spent $3,649 on Facebook advertising to promote Parker’s campaign.

The PAC, which filed paperwork with the Federal Ethics Commission in January and the Texas Ethics Commission last week, has yet to report any spending. It also has not yet disclosed its donors. A source familiar with the PAC’s plans confirmed that it is a Perry effort.

Federally, its treasurer is Bill Jones, an attorney who served as Perry’s general counsel. The Texas paperwork lists as “expenditure decision makers” Jones and two others: Janelle Shepard, a Perry appointee to the State Commission on Judicial Conduct and the Texas Higher Education Coordinating Board, and Steve Cortes, who served on the advisory board of a PAC Perry created ahead of his 2016 presidential campaign.

Neither Jones nor a representative for Perry returned requests for comment. In an interview, Parker insisted she had “never heard of” the group and hadn’t been aware of its planned ad spend.

She said her campaign has been “very grassroots,” with no big checks from Perry or his affiliates. But “I’m not going to turn down support,” she said.

Parker is positioning herself as the candidate of conservative activists, with endorsements from the political action committee of Grassroots America — We the People; Texas Values Action; Texans for Courageous Courts, an arm of Empower Texans; and several anti-abortion groups. Among her supporters is Steven Hotze, an anti-LGBTQ GOP activist and donor.

The greatest differences between Parker and Richardson, she said, are “philosophical.”