Updated Saturday at 4:20 p.m. with more examples of lopsided congressional delegations in other states.

WASHINGTON — Texas Republicans collected half of the votes statewide in congressional races this month. ­But even after Democrats flipped two districts, toppling GOP veterans in Dallas and Houston, Republicans will control 23 of the state’s 36 seats.

It’s the definition of gerrymandering.

“You wouldn’t expect perfect proportionality, but when something is really skewed, that’s probably a sign that something’s amiss,” said redistricting expert Michael Li.

Demographically and politically, the state is evolving — faster in some places than in others. Many Texas Republicans in Congress faced surprisingly close calls in the 2018 midterms.

Boundaries drawn early this decade to maximize GOP power blunted the damage. But the bulwarks built after the last census have begun to weaken. The midterms exposed unexpected shortcomings as college-educated white women — traditionally a major source of votes for the Texas GOP — abandoned the party.

Some were repelled by President Donald Trump and, at the same time, intrigued by Rep. Beto O’Rourke, the El Paso Democrat who offered a vision of less confrontational leadership, albeit with a liberal bent.

In Dallas, lawyer and former pro football player Colin Allred ousted Rep. Pete Sessions, a member of the GOP leadership. In Houston, lawyer Lizzie Pannill Fletcher unseated Rep. John Culberson, who led a subcommittee that controls billions in federal spending.

Both districts have seen some of the fastest demographic shifts in the state, with the nonwhite share of the electorate rapidly shrinking. They were stocked with high-income, highly-educated white voters long presumed to be Republican; many turned out to be swing voters under the right circumstances.

“These districts ... weren’t built to elect Republicans in the age of Donald Trump,” said Li. “The Republican Party of today is almost unrecognizable to people of 2011.”

Independents in Texas have been in the habit of backing Republicans.

"But they can be re-educated to see Democrats as an option," said Steve Bickerstaff, a retired University of Texas adjunct law professor whose books include Lines in the Sand, about the 2003 redistricting fight in Texas.

1 / 7U.S. Rep. Beto O'Rourke greeted Adam Bell, a Democratic candidate for Congressional District 3, after O'Rourke addressed a town hall at Plano High School in November 2017.(Smiley N. Pool / Staff Photographer) 2 / 7Democrat Colin Allred greeted a supporter after speaking during an election night party after he was projected to win the 32nd Congressional District. Allred defeated Rep. Pete Sessions.(Andy Jacobsohn / The Associated Press) 3 / 7Rep. Pete Sessions introduced Vice President Mike Pence during a campaign event in Dallas in October.(Cooper Neill / The New York Times) 4 / 7Lizzie Pannill Fletcher smiled as results were announced in her race against John Culberson for the 7th Congressional District.(Brett Coomer / Houston Chronicle) 5 / 7U.S. Rep. John Culberson gave his concession speech at an election night party in Houston on Nov. 6, 2018.(Loren Elliott / Getty Images) 6 / 7Sen. Ted Cruz, R-Texas, spoke during a rally at Gilley's in Dallas on Oct. 24, 2018.(Daniel Carde / Staff Photographer) 7 / 7President Donald Trump spoke during a campaign rally for Sen. Ted Cruz, R-Texas, at Houston's Toyota Center in late October.(Evan Vucci / The Associated Press)

Trump, O'Rourke factors

Both parties engage in gerrymandering when they can, in Texas and around the country.

Democrats enjoy a lopsided split in the two biggest states they control: 21 of 27 seats in New York (78 percent), and 46 of 53 seats in California (87 percent). In both states, they drew about two-thirds of votes in congressional races this month.

Republicans have held a tight grip on Austin since 1998, when they swept statewide elections and opened an era of one-party rule that has lasted two decades.

But O’Rourke came within 2.6 percentage points of Sen. Ted Cruz. O'Rourke's coattails, combined with the drag Trump put on the GOP, showed that the 2012 map doesn’t provide as much certainty as it used to.

“In Texas, you have pretty polarized voting by racial lines. So if you just draw districts to minimize the African-American and Latino vote, you go a long way to having an advantage for Republicans,” said Li, a senior counsel at the Brennan Center for Justice at New York University. “It’s mostly worked this decade. It partially collapsed this election in a couple of districts that tell you a little bit why gerrymandering is harder in Texas than in other states, because Texas is changing so fast.”

In two GOP-held districts that Trump carried, O’Rourke topped Cruz. That helped fellow Democrats come much closer than expected.

In the Dallas-area 24th District, Rep. Kenny Marchant, R-Coppell, survived with a margin of just 3 percentage points over a little-known challenger he outspent 11-1.

In suburban Houston’s 2nd District, Rep. Ted Poe notched 2-1 blowouts for years. He retired this year. Dan Crenshaw, a retired Navy SEAL who lost an eye in Afghanistan, won by 7 points. National Democrats might have paid attention to the race had they recognized the opportunity.

O’Rourke fought Cruz nearly to a draw in the 6th District, where Arlington Rep. Joe Barton’s retirement paved the way for his former chief of staff Ron Wright, the Tarrant County tax assessor-collector.

There, the map enacted by the Legislature after the 2010 census operated as intended: Democratic nominee Jana Lynne Sanchez ran up the score in Tarrant County precincts, but conservative voters in Ellis County put Wright over the top.

Rep. Michael McCaul, R-Austin, outspent his challenger 4-1 in a district that runs from the west side of Houston to the east side of Austin. The rural midsection kept the outgoing House Homeland Security chairman in his seat with a narrow, 4-point win.

Just north of Austin, Rep. John Carter, another senior Republican, beat M.J. Hegar by 3 points in a district that Trump carried by 13 points.

“Those districts were gerrymandered to absorb Democrats,” said Matt Angle, a veteran Democratic strategist who has been involved in Texas redistricting fights for two decades. “There are some of these congressional districts that Beto defined as more in play than any of us thought. ... Those exurban areas are getting away from them.”

At this rate Rs will have no choice but to draw a new safe Dem Austin vote sink when TX gains seats in 2022, much as Rs did in Columbus, OH in 2012. https://t.co/aTjEMBhvgU — Dave Wasserman (@Redistrict) November 21, 2018

Other lopsided states

Texas is hardly the only state whose partisan ratio in Congress is out of whack.

North Carolina’s split has been 10-3 in favor of Republicans all this decade. In Ohio, Republicans hold 12 of 16 seats. Yet in both states, the parties are at near-parity in statewide voting.

“You might as well not have elections,” said Li.

In Pennsylvania, which like Ohio has one senator from each party, voters picked Barack Obama twice and Trump in 2016. Yet Republicans nabbed 13 of 18 House seats in the last three elections.

In January, the state Supreme Court struck down that map and imposed a new one. This month, Democrats and Republicans split the pie in half: nine seats each.

In March, the Brennan Center published a study titled “Extreme Gerrymandering & the 2018 Midterm.”

The closer the correlation between votes and seats, the higher the responsiveness. Texas has an especially “nonresponsive” map, where even a huge jump in the minority party’s share of votes isn’t likely to yield much gain.

Heading into the 2018 midterms, Texas Democrats held 11 of 36 seats. Brennan projected that getting to 13 would be nearly impossible unless they topped 51 percent of the vote statewide. They managed it with 47 percent.

Li credits the combination of the Trump and O’Rourke factors.

“Whether that’s a realignment or a blip remains to be seen,” he said.

Still, Texas Democrats would have four more seats in January if their share of districts tracked their share of votes.

“That defines gerrymandering. Texas is racially and politically gerrymandered in an egregious way,” Angle said.

1 / 5Texas state Democratic representatives held hands in prayer to open their morning session in a conference room at the Holiday Inn in Ardmore, Okla., on May 14, 2003. The Texas Democrats left the state in protest over proposed redistricting by Republican leadership in the Texas House. (File Photo / Staff) 2 / 5Texas state Democratic representatives held a copy of the Austin American-Statesman on May 14, 2003. The Democrats left the state in protest over proposed redistricting by Republican leadership in the Texas House. (File Photo / Staff) 3 / 5Texas Democratic representative Trey Martinez Fischer (right), from San Antonio, sat with the press to film a news conference on May 13, 2003, at the Holiday Inn in Ardmore, Okla., where over 50 representatives were staying.(File Photo / Staff) 4 / 5U.S. House Majority Leader Tom Delay, R-Sugar Land, left the office of Texas House Speaker Tom Craddick, heading to Lt. Gov. David Dewhurst's office, in October 2003 as he tried to end a redistricting standoff. (File Photo / Staff) 5 / 5U.S. House Majority Leader Tom Delay, R-Sugar Land, walked through the Texas Capitol with U.S. Rep. Kevin Brady, R-The Woodlands, on Oct. 6, 2003, as they tried to resolve a redistricting standoff.(File Photo / Staff)

In 1992, the last time Democrats controlled Texas government and redistricting, they won 21 of 30 U.S. House seats with just under half of the statewide vote — a far more lopsided outcome than the one Republicans achieved in the past several elections.

Texas had been awarded three new seats after the 1990 census. Those were drawn to ensure minority control. The rest, recalled Angle, were drawn to protect incumbents in both parties — creating a slow-motion shift.

When John Bryant quit to run for the Senate, Sessions replaced him. In the 1994 Republican Revolution, Mac Thornberry defeated Bill Sarpalius, and Steve Stockman ousted Jack Brooks. (The Democratic takeover ends Thornberry's stint as Armed Services chairman. Stockman recently got a 10-year prison term for stealing contributions.)

“That map was an incumbent gerrymander. It was not a Democratic gerrymander,” Angle insisted.

Li views that distinction as blurry, noting that most incumbents at that time were, in fact, Democrats.

The most contentious redistricting fight in Texas and, perhaps anywhere, came in 2003 when Tom DeLay, then the U.S. House majority leader, prodded Republicans in Austin to take a second crack at congressional lines — an unprecedented mid-decade redistricting.

Democratic state lawmakers fled to Oklahoma and New Mexico but couldn’t stall forever.

The new map took aim at 10 Anglo Democratic incumbents. Eight were pushed out or defeated.

“The plan was a master of gerrymandering,” said Bickerstaff, the retired attorney. DeLay "was trying to make the Democratic Party unattractive to non-Hispanic white voters and candidates by making all of the elected officials either black or brown.”

Areas of Democratic strength were carved up. Travis County was split five ways. Dallas and Tarrant counties also were divided to dilute Democratic voting strength, Bickerstaff said.

Republicans claimed 21 of 32 seats, with 58 percent of the statewide votes.

Texas gained four seats after the 2010 census. With the same 58 percent vote, Republicans claimed two-thirds of the seats. Growth this decade puts Texas on track to gain two or three more seats after the 2020 census.

Bickerstaff pointed out that Democratic turnout spiked in 2018, so this year wouldn’t be a good benchmark to say how many seats each party should win. But, he said, “If there has been any change, it has favored the Democrats.”