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Six gone, and counting: It usually takes a brutal round of redistricting to get rid of this many members of the Texas congressional delegation.

This is not yet a record, but the quitting season has a couple of weeks left. Not everyone in the state’s 36-member delegation to the U.S. House has filed for re-election, but just a few months ago, nearly all were expected to.

Things changed rapidly; at least a sixth of those people are leaving, and more could join them.

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The Texas Politics Project at the University of Texas at Austin posted a helpful recent history on congressional turnover; what’s notable here is the number of voluntary departures. A half-dozen members of the state’s congressional delegation have announced they won’t seek re-election in 2018:

That doesn’t mean the other 30 seats Texas holds in the U.S. House won’t change. U.S. Rep. Joe Barton, R-Ennis, is embroiled in a sex scandal that began with a naked selfie or video sent to a romantic partner during a separation before the congressman’s divorce. That came to light when someone posted on social media what Barton had apparently hoped was a private image. After The Texas Tribune’s Abby Livingston broke that story, the Washington Post followed, reporting that Barton had threatened an unidentified woman he would go to the Capitol Police in Washington if she exposed his behavior.

Now he’s got the Fort Worth Star-Telegram and some folks back home, including Tim O’Hare, the chairman of the Tarrant County GOP, asking him to step aside. He’s attracting new opponents into a re-election race that, without the revelations, should have been an easy one.

If he heeds those voices in his 6th Congressional District, he could become Number Seven.  

It usually takes an earthquake to have this kind of political turnover. Redistricting does to a political map what a real earthquake does to the landscape; the last time Texas saw this many new people in its congressional delegation was more than a decade ago. Democrats were in the House majority in 2001, when the Texas Legislature was supposed to draw new political maps. Political differences kept the Legislature from finishing the job and the Legislative Redistricting Board, a gathering of high state officials that included four Republicans and one Democrat — finished it for them.

Republicans took the majority in the House  after the 2002 elections that used those maps (Republicans took the Texas Senate after the 1996 elections). They selected the first Republican state House speaker since Reconstruction — Tom Craddick of Midland. And then they proceeded, with help and prodding from then-U.S. Rep. Tom DeLay, R-Sugar Land, to redraw those political maps — an unusual mid-decade effort to make the maps more Republican than they already were.

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It worked. With defeats of six Democrats and one party change (Democrat Ralph Hall of Rockwall joined the GOP), the 2004 elections flipped the majority of the state’s congressional delegation to the Republicans for the first time in more than a century.

This time, the delegation isn’t even waiting for the state’s voters. Three incumbent Republicans — John Culberson of Houston, Will Hurd of Helotes and Pete Sessions of Dallas — are in seats that have drawn the interest of Democrats. Those congressmen were re-elected in 2016, but Hillary Clinton beat Donald Trump in their districts — a result that has attracted the interest of Democrats looking for possible pickups.

The rest of the state’s seats are considered safe, at least on paper, for the parties that now hold them. While it would be a genuine political upset to flip any of those in November, the primaries aren’t necessarily secure for incumbents.

All that is a way of saying six incumbents in the delegation are voluntarily leaving, and others might join them before the Dec. 11 deadline for candidate filing. And after that, 2018’s March 6 primaries and Nov. 6 general elections might further add to those numbers.

Even those winners won’t be secure for long. The next redrawing of the Texas maps is not far away, falling right after the 2020 census. 

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