GOP maps are designed to weaken Democrats on Election Day, Duke math expert says

CHARLOTTE, N.C. — New election maps drawn by Republican legislators show clear signs of gerrymandering designed to elect fewer Democrats, a Duke University mathematician said Wednesday.

© Travis Long/The News & Observer/TNS Several dozen members of the public wait to address state lawmakers during a public comment hearing on Senate and House legislative redistricting maps Monday, Oct. 15, 2021 at the Legislative Building in Raleigh, North Carolina.

Jonathan Mattingly, who has served as an expert witness in court cases that overturned previous GOP-drawn maps, said the latest round of redistricting produced maps that are far less “responsive” to voters than those drawn without partisan consideration.

Load Error

“This is really one of the hallmarks of a map that’s gerrymandered and that will tend to under perform for one party,” Mattingly said during a virtual briefing for reporters.

To reach those conclusions, Mattingly and his team used an automated technique to draw tens of thousands of maps using the legislature’s own established redistricting criteria.

Those rules include keeping counties and cities whole, making districts as compact as possible and excluding partisan and racial data.

Yet when Duke researchers used historical election results to simulate outcomes under new maps drawn for the U.S. House, state House and state Senate, they found that GOP proposals almost always elect more Republicans than most maps in the computer-generated collection.

© Travis Long/The News & Observer/TNS Top state redistricting legislators, Sen. Paul Hise, top left, and Rep. Destin Hall, top right, listen as several dozen members of the public address state lawmakers during a public comment hearing on Senate and House legislative redistricting maps Monday, Oct. 15, 2021 at the Legislative Building in Raleigh, North Carolina.

That’s true even in elections with strong Democratic turnout.

“From a very strong Republican majority to a pretty strong Democratic majority, in historical terms, we see almost no change in the outcome here,” Mattingly said.

The maps also show clear evidence of “packing” and “cracking” — techniques to stuff noncompetitive districts with voters of the opposing party or split those voters up to dilute their political power, Mattingly said.

“These districts that are the ones that are in play have many, many less Democrats than we’d typically see,” Mattingly said. “The districts that are very safe for Democrats have a lot more Democrats, so they’ve been packed in it. And the districts that are very safe for Republicans actually have less Republicans, still leaving them safe.”

Despite its status as a purple state, North Carolina has traits that naturally result in more Republican representatives in the legislature and U.S. House delegation. That’s the result of winner-take-all elections and political self-sorting in North Carolina, where Democrats are often densely clustered in cities.

But the Duke team’s computer-generated maps, Mattingly said, have that “natural” packing built-in.

“You still see a dramatic under-electing of Democrats, even when you take that into account in that map,” Mattingly said. “So there is definitely a tilt beyond what would be accounted for by geographic packing in the North Carolina House, for example, and also when you look at some of the other maps too.”

Republican leaders, though, are so far unconvinced.

“In general, people should be skeptical of algorithms that attempt to model human behavior. Human decisions, especially people’s voting choices, are very complex and can’t be precisely modeled by any computer. Candidates and the issues of the day are different across elections,” Republican Sen. Ralph Hise, one of the three co-chairs of the Senate Redistricting Committee, said in a statement Wednesday. “Voters can’t be boiled down into just generic Republicans or Democrats, as the election results in Virginia just yesterday proved.”

Pat Ryan, a spokesperson for Senate Republicans, said Wednesday he’d need more details on the Duke team’s analysis of congressional map proposals before commenting.

The research is likely to loom large in future court cases over the maps as the fight over redistricting continues. Mattingly’s findings played prominently in a partisan gerrymandering case before the U.S. Supreme Court and subsequent state cases that forced Republican leaders to draw new, less partisan maps in 2019.

Even with an explicit ban on past voting data, such statistical evidence might prove to judges that districts were drawn “to stack the deck before the first vote is cast,” said Sen. Dan Blue, a Democrat on the Senate Redistricting Committee who has been involved in political mapmaking for decades.

“If the mathematics says that the chances are 1 in 100,000 that this is a map that you would end up with if you were not using partisan data, then that’s evidence that you probably used partisan data,” Blue said in an interview with The News & Observer Wednesday.

Although the maps aren’t a done deal yet, the end of the legislative process, at least, is near.

The state House passed a bill for its new district lines Tuesday night, and the state Senate did the same for its own map Wednesday. Nothing is likely to change as the maps wait for approval in opposite chambers.

A plan for the state’s U.S. House districts passed the Senate Tuesday and is awaiting approval in the House.

Gov. Roy Cooper, a Democrat, has no veto power over the redistricting plans, which are expected to pass with Republican majorities during final votes in the coming days.

Then it will be up to the courts, where one lawsuit has already been filed.

Mattingly said he was “disappointed” in the proposal for the congressional maps, but said he remains hopeful that North Carolina will see maps that are more responsive to voters in the future.

“This happens on both sides of the aisle. Both parties do this across the country, and so I would like us, as a country, to get out of the gerrymandering business nationally,” Mattingly said. “I would think that would be great for how we feel about our democracy.”

———