‘A systematic pro-Republican bias:’  Experts open North Carolina redistricting trial with evidence of extreme partisan gerrymandering

Voting Rights

Raleigh, N.C. (January 3, 2022) — North Carolina’s redistricting trial kicked off Monday with expert testimony establishing the state’s Republican lawmakers used 2021 voting maps to give themselves an extreme partisan advantage in state legislative and congressional elections. 

Plaintiffs’ first witness, Dr. Jowei Chen, a Political Science professor at the University of Michigan, focused on the congressional districts in comparison to 1,000 simulated voting maps using prior election data. Dr. Chen concluded the Republican bias apparent in North Carolina’s enacted map could not be explained by the state’s political geography nor lawmaker’s own map-making criteria. In particular, Dr. Chen called the enacted congressional maps, which give Republicans at least 10 House seats out of 14, a “partisan outlier.” 

“The enacted plan both at a statewide level and individual districts is a statistical outlier in its partisanship,” testified Chen. “There are going to be fewer competitive districts.”  

Western Carolina University Political Science and Public Affairs Professor Dr. Christopher Cooper analyzed enacted maps based on voter attitudes, demonstrating how new maps fail to reflect the state’s current political landscape. Referring to the newly-enacted Congressional District 11 which spans from Guilford to Watauga County, Cooper told the court that, based on any criteria from geography to media markets, “there’s nothing that ties these areas together with other than the fact they happen to be in the state of North Carolina.” 

Dr. Cooper confirmed that while Democratic-leaning areas are largely responsible for the population growth justifying an additional Congressional seat, “Democratic representation will decrease under the current map.” 

Dr. Jonathan Mattingly, Professor of Mathematics at Duke University, who generated 100,000 maps in his analysis, also testified that Republican maps are partisan outliers — even after comparing multiple election outcomes. 

“None of the maps we see have any chance at [the enacted map’s] outcome,” said Mattingly.  “I found them to have a systematic pro-Republican bias.”  

Dr. Wesley Pegden, Department of Mathematics at Carnegie Mellon University closed out the day’s expert testimony. His analysis made random changes to enacted maps to test how carefully they were designed to create a partisan advantage. Dr. Pegden told the court  his findings showed that the enacted map “is more optimized for partisanship than 99.999% of all possible maps.”

“You can’t always detect partisan intent,” said Dr. Pegden. “But when you do detect it, you can be highly confident.” 

Day two of the North Carolina League of Conservation Voters et al. and Harper et al. and Common Cause v. Hall trial begins at 9 a.m. on Tuesday, January 4. Attorneys for the legislative defendants will continue their cross examination of Dr. Wesley Pegden.  

SCSJ will live-tweet the trial on Twitter at @scsj using the hashtag #ncredistrictingtrial and continue to promote WRAL’s live video feed at scsj.org/ncmapstrial.


Sailor Jones, sailor@scsj.org, 919-260-5906, SCSJ

Gino Nuzzolillo, gino@scsj.org, 402-415-4763, SCSJ

Melissa Boughton, melissa@scsj.org, 830-481-6901, SCSJ

Bryan Warner, BWarner@commoncause.org, 919-599-7541; Common Cause NC


The Southern Coalition for Social Justice, founded in 2007, partners with communities of color and economically disadvantaged communities in the South to defend and advance their political, social, and economic rights through the combination of legal advocacy, research, organizing, and communications. Learn more at southerncoalition.org and follow our work on TwitterFacebook, and Instagram.