Analysis: The biggest threat to Texas Republicans? Texas Republicans.

Texas Elections 2018

U.S. Sen. Ted Cruz defeated Democratic challenger Beto O'Rourke in the race for U.S. Senate. View full 2018 Texas election results or subscribe to The Brief for the latest election news.

 More in this series 

_{Editor's note: If you'd like an email notice whenever we publish Ross Ramsey's column, click here.}

The Republican big tent shares a risk with big family reunions; everybody shows up, and the name is sometimes the only thing they have in common.

In the latest installment of the GOP’s family feud, Gov. Greg Abbott, a Republican whose own state representative is a Democrat, came out against a Republican Houston incumbent this week by backing the GOP challenger to state Rep. Sarah Davis in the lead-up to next year’s March 6 primary.

This is a big deal. Texas governors generally don’t endorse against incumbents, never mind endorsing against incumbents in their own party. Sure, this is politics and politics ain’t beanbag and all that. But this puts a sort of official stamp on a split in the GOP that so many Republicans won’t even acknowledge.

In a recent email to supporters, U.S. Sen. Ted Cruz nodded to that, saying, “The media continues to pit Republicans against each other in squabble after squabble ...” But here’s Abbott putting a squabble on his list of things to do in the next four months. He’s not done, either: Aides told The Texas Tribune’s Patrick Svitek that he’s likely to add more Republican incumbents to the list.

It might not work in mailers from Republican senators like Cruz, but Abbott’s works — and those of the state’s lieutenant governor — are pretty good evidence that some of the folks at the Texas GOP’s family reunion would like to throw out some of their political kin.

Susanna Dokupil, an assistant solicitor general when Abbott was the state’s attorney general, will have the governor’s support — for what that’s worth — against Davis in the Republican primaries. What that is worth depends on the governor himself. Two Republican incumbents — Doug Miller of New Braunfels and Wayne Smith of Bay City — lost their runoffs in 2016 in spite of Abbott’s endorsements. His name alone was not enough to save them. But the governor, who has a huge campaign account and no formidable opposition in his own bid for reelection, could bring heavy artillery to back up his choices in legislative races.

There’s a tie here to one of Abbott’s perennial “emergency issues” for the Legislature: His call for ethics reform. He seems more interested in it for other officeholders than himself. The governor’s office bristled — governors have minions to do that for them — earlier this year when the House overwhelmingly supported a bill that would have barred big donors to governors from gubernatorial appointments to state boards and commissions. Some lawmakers believe that’s a little too blatant a case of quid pro quo. For this governor and his predecessors, fancy seats for big givers is simply the way things are done.

Davis wasn’t the author of that gem — state Rep. Lyle Larson was. He might be on Abbott’s hit list before this is over. But Davis was part of the club, and one of the noisiest critics when Abbott didn’t put ethics reform, an issue he declared an “emergency” earlier this year and two years ago in his first session as governor, on the list of 20 things he wanted done during the summer’s special session.

If the governor is successful, Davis won’t be one of the thorns in his paw for much longer. It would tell the surviving members of the Legislature that crossing the governor has real costs. It would tell members of the more conservative Senate that the governor is on their side of the bubbling Senate v. House turbulence that colored this year’s legislative debates.

It also puts the governor’s thumb into the race for speaker of the House. Joe Straus, the current speaker, is leaving. The people elected to the House in 2018 — a group that will include Davis or Dokupil or a Democrat who beats the Republican nominee — will select the next speaker. Abbott evidently wants more people in that chamber that vote like the state’s conservative senators, and picking off the least-conservative members of the House is a way to move things in that direction.

Abbott isn’t the Texas GOP’s only cannibal. Lt. Gov. Dan Patrick’s campaign consigliere, Allan Blakemore, has signed on to run a challenge to state Sen. Kel Seliger, an Amarillo Republican who doesn’t always toe the movement conservative line favored by Patrick.

The two leaders are trying some political behavior modification on their own party. They can’t kill many more Democrats, but the Republican-drawn House and Senate political maps have minimized the danger from the minority party. They’re trying to straighten their own ranks, to remove obstacles within their own party that have successfully blocked or slowed their agendas.

And they’re betting Republican primary voters are with them. Davis answered Abbott’s endorsement of her challenger with a cautionary note, noting Hillary Clinton’s 15-point advantage over Donald Trump in her district and pointing to that as evidence that a moderate Republican is what her voters want. Electing a more conservative Republican in the March primary, she said, risks a Democrat winning the seat in November.

They can’t all be right.