Republicans are about to find out whether their gerrymanders backfired

Two decades ago, political scientists identified a certain breed of self-defeating gerrymander that backfired on mapmakers who tried to rig congressional district lines for partisan advantage.

They called it a “dummymander.”

“A dummymander is a gerrymander by one party that, over the course of the decade, benefits the other party, and actually looks as if it was designed by that party rather than the party in power,” Bernard Grofman and Thomas Brunell wrote in “The Art of the Dummymander.”

The phenomenon came out of Democratic legislatures in the Deep South in the 1990s. Attempting to protect incumbents amid a political realignment toward Republicans, they spread what was left of their voting strength across too many districts after the 1990 census.

Grofman and Brunell compared their situation to a lifeboat. “The carrying capacity of any lifeboat is limited,” they said. “If you try to overload it, the boat may sink, or at least tip over, washing a number of people overboard.”

Over the last two years, Democrats and Republicans have battled to redraw House districts, in a process kicked off by Texas Republicans’ adoption of a new map — at the direction of President Trump — that shifted as many as five seats their way. Other states joined in, including retaliation by Democrats in California. Courts blocked some of both parties’ efforts, with the resulting national map tilted toward Republicans by about nine seats, on net.

Now, as analysts forecast a potential “blue wave” of support for Democrats, election watchers are studying whether Republicans’ efforts could backfire. The upshot? Probably not this year. But the election will test just how much partisan advantage mapmakers can squeeze out before a gerrymander starts working against them.

‘A perfect storm’

The Democrats’ 1990s dummymander wasn’t apparent immediately: For one election, in 1992, the Democratic maps worked. Across North Carolina, South Carolina and Georgia, Democrats won 18 of 29 House seats. Their only misstep: In trying to gerrymander Republican Newt Gingrich out of his district, they forced him to move to a new district where he won narrowly.

Two years later, the weather turned. Gingrich led the “Republican Revolution” during President Clinton’s first midterm and was rewarded with the speaker’s gavel. The 18 dummymandered Democratic seats were reduced to 10.

Today’s potential dummymanders are different. For starters, House districts are meant to be redrawn once a decade, following the U.S. census. The Democratic dummymanders in the ‘90s came after constitutionally required reshuffling. The mid-decade gerrymanders of 2025 and 2026 were purely opportunistic. Republican-led states such as Texas and Florida redrew maps at Trump’s urging, not to protect vulnerable seats, but to extend their partisan advantage.

These gerrymanders are also different in that they could conceivably backfire in their first election, rather than producing the delayed reaction of the Southern Democrats’ earlier dummymander.

“We are in a perfect storm for dummymanders,” said Brunell, now a political science professor at the University of Texas at Dallas. The formula: extreme partisan gerrymandering — mostly by Republicans — and a midterm election with an unpopular president and economic headwinds.

Margin for error

Some dummymanders are dumber than others. The real test isn’t whether Republicans lose seats in Tuesday’s elections — it’s whether they’re left worse off than if they had left the old districts in place. “There can be degrees of dummyness,” Brunell said.

Republicans drew their maps to withstand a blue wave that crests at about a 10- to 12-point margin. The RealClearPolitics average of generic congressional polls now gives Democrats an advantage of just over 8 points — meaning that if the polls are broadly right, Republicans will still likely end up benefiting from the new maps.

Jonathan Cervas, a Carnegie Mellon University professor who has drawn his own maps as a court-appointed special master, said a true dummymander seems unlikely and is “wishful thinking” by Democrats.

And even if it happens, Cervas argues, it won’t be bad mapmaking that loses the House for Republicans, who now control the chamber by just a few seats.

“Everything is so nationalized that the shifts that happen in Texas are the same shifts that happen everywhere,” Cervas said.

Assuming that voters move toward Democrats in roughly equal measures across the country, Republicans will have lost dozens of competitive districts in states that weren’t redrawn — such as Michigan, Pennsylvania, Arizona, Iowa, Wisconsin and Colorado — before any blue wave gets to Texas and Florida.

“At that point,” said Cervas, “it would not have mattered because they would have lost so many seats anyway.”

Korte writes for Bloomberg. Adrienne Tong of Bloomberg contributed to this report.