A new congressional map adopted by Republican legislators earlier this month guarantees Republicans four safe U.S. House seats, two expert witnesses for the plaintiffs challenging the state’s allegedly gerrymandered maps testified in court Thursday.
Jowei Chen, a political science professor at the University of Michigan, used an algorithm to generate 10,000 maps based on Utah’s neutral redistricting criteria to compare the maps to the Legislature’s preferred option.
More than 99% of those computer-generated maps created at least one district that favored Democrats, Chen said, while the Legislature’s map does not, making it an “extreme partisan outlier” that favors Republicans.
(Francisco Kjolseth | The Salt Lake Tribune) Jowei Chen, an associate professor at the University of Michigan, testifies during a hearing regarding congressional district maps before Judge Dianna Gibson in 3rd District Court in Salt Lake City on Thursday, Oct. 23, 2025.
Chris Warshaw, a professor at Georgetown University, expressed a similar sentiment. Based on his analysis, using multiple metrics, Warshaw said the test results “suggest the [Legislature’s] enacted map unduly favors the Republican Party and the other proposed maps from the plaintiffs are politically neutral and do not favor either party.”
The dual testimonies came Thursday, the first in a two-day hearing before 3rd District Judge Dianna Gibson, who will decide which of three maps — either one chosen by the Legislature or two options submitted by the plaintiffs — complies with the standards in Proposition 4, also known as the Better Boundaries initiative.
That initiative, passed by voters in 2018, sought to set standards for drawing Utah’s political boundaries, including prohibiting drawing districts to benefit one party to the detriment of another. The Legislature essentially repealed the initiative, but the plaintiffs in the case — the League of Women Voters, Mormon Women for Ethical Government and a number of residents impacted by the congressional maps — sued.
(Francisco Kjolseth | The Salt Lake Tribune) Judge Dianna Gibson holds a hearing regarding congressional district maps in 3rd District Court in Salt Lake City on Thursday, Oct. 23, 2025.
The Utah Supreme Court ruled last year that action by the Legislature was unconstitutional, since it deprived Utahns of their right to the initiative.
Based on that decision, Gibson ruled in August that Proposition 4 is the law in Utah and directed the Legislature to draw a new map that complies with the ballot measure.
She has until Nov. 10 to decide between the three options and have a map in place so county clerks can make preparations for the 2026 midterm elections.
Chen testified that, based on his analysis, the map adopted by the Republican-dominated Legislature “cracked” Democratic voters to create four safe GOP districts.
Public hearings on GOP plan
While parties are arguing over how to redraw Utah’s congressional boundaries, the state Republican Party is driving an “indirect initiative” to repeal Proposition 4.
If they gather 70,374 valid signatures statewide, the Legislature would have to have an up-or-down vote on repealing the 2018 voter-passed initiative banning gerrymandering. While the Utah Supreme Court has ruled it is unconstitutional to repeal a citizen-backed initiative, the belief is that this indirect initiative — which has never been used in Utah — would trump the 2018 ballot measure.
Before the Republicans can begin gathering signatures, though, they have to hold a series of seven public hearings around the state. All seven hearings are scheduled for Saturday. None is in Utah’s capital, Salt Lake City:
Southwest Region
Washington Branch Library
220 N. 300 East
Washington, UT
5:30 p.m.
Bear River Region
Logan Library
285 N. Main
Logan
4 p.m.
Wasatch Front Region
Davis County Headquarters Library
133 S. Main
Farmington
10:30 a.m.
Uinta Basin Region
Uintah County Library
204 E. 100 North
Vernal
11 a.m.
Central Region
Sorensen Administration Building
800 W. 200 South
Richfield
10 a.m.
Southeast Region
Jennifer Leavitt Student Center
451 E. 400 North
Price
6 p.m.
Mountain Region
Lehi Broadbent Room
128 N. 100 East
Lehi
10:30 a.m.
Split counties
He also criticized the ensemble of more than a quarter million computer-generated maps produced by two expert witnesses for the Legislature — Sean Trende, a commentator for RealClearPolitics, and Michael Barber, a political science professor at Brigham Young University — which he said failed to follow basic redistricting criteria.
Trende’s maps, Chen said, needlessly split counties and created districts that were not compact — two of the highest priority redistricting criteria. Chen said none of his 10,000 maps had more than three county splits while more than half of Trende’s maps had at least seven split counties and some of them as many as 13.
When maps have districts with too many county splits or that are not compact, Chen explained, they tend to create safe GOP seats — since putting random voters into sprawling random districts makes it more likely the districts will reflect the state’s overall Republican advantage.
Chen argues that maps that don’t comply with the redistricting standards in law should not be used as a baseline with which to compare the legislative map. In fact, he said, if maps that needlessly split counties were not part of the comparison Trende used, the Legislature’s map would have failed the “partisan bias” test that lawmakers established.
(Francisco Kjolseth | The Salt Lake Tribune) Soren Geiger, attorney for the Utah Legislature, cross-examines witness Jowei Chen, an associate professor at the University of Michigan, during a hearing regarding congressional district maps before Judge Dianna Gibson in 3rd District Court in Salt Lake City on Thursday, Oct. 23, 2025.
Soren Geiger, an attorney hired by the Legislature, pressed Chen on the algorithm he used to generate his maps and why thousands of the scholar’s maps basically looked the same, creating a strong Democratic district in the northern portion of Salt Lake County.
Chen said that, to avoid splitting Bluffdale and Draper, which straddle the boundary between Salt Lake and Utah counties to the south, and deal with the natural barrier of the Great Salt Lake to the north, a district centered in northern Salt Lake County is a natural product of the neutral redistricting criteria.
Geiger pressed Chen on whether an east-west split of Salt Lake County would not also address the issue. The professor conceded it would but said he believes some portion of his maps did.
(Francisco Kjolseth | The Salt Lake Tribune) Professor Christopher Warshaw of Georgetown University testifies during a hearing regarding congressional district maps before Judge Dianna Gibson in 3rd District Court in Salt Lake City on Thursday, Oct. 23, 2025.
The ‘Utah paradox’
Warshaw’s testimony focused on the tests put into law by the Legislature as the only methods that could be used to detect if a map is gerrymandered. The tests the Legislature chose, he said, are a poor fit for a state like Utah, which has just a few congressional districts and one dominant party.
When the “partisan bias” formula chosen by the Legislature is applied to Utah, maps that favor Democrats actually produce scores that would indicate the map is an extreme pro-Republican gerrymander and fail the test, while maps with four Republican seats pass the test, Warshaw said.
Academics have referred to the phenomenon as the “Utah paradox.”
The second test, the mean-median test, is “among the worst measures” for a state like Utah, Warshaw said, since Democrats could realistically only win one seat in Utah, but the mean-median test looks at the partisan tilt of the second- and third-most-Republican seats — which are is not a useful measure.
Warshaw said there are other tests, like the “efficiency gap” — which measures the percentage of votes “wasted” by a party because the party can’t convert its votes into a victory — that could provide a better barometer.
On cross-examination by legislative attorney Olivia Rogers, Warshaw acknowledged that tests like the efficiency gap also are susceptible to anomalous results in a state with just a handful of districts, but he said that is a reason to consider a variety of tests and not choose just a few that he said are “among the worst” measures for a state like Utah.
Chen also said that, based on his analysis, the partisan bias test by the Legislature failed nearly all of the maps that would have created a Democrat-leaning district and was much more likely to pass Republican-leaning maps.
Gibson also heard testimony from Malcolm and Victoria Reid, Millcreek residents who are among the individual plaintiffs in the lawsuit. The couple spoke about why they supported the 2018 Better Boundaries initiative.
“I would like to feel we can have our voice heard consistently,” Malcolm Reid said, “not only at the local level, at the federal level.”
(Francisco Kjolseth | The Salt Lake Tribune) Plaintiffs Malcolm and Victoria Reid attend a hearing regarding congressional district maps before Judge Dianna Gibson in 3rd District Court in Salt Lake City on Thursday, Oct. 23, 2025.
Reid said that, while he can still vote, he feels his voice is less effective when the people in charge have “carved up” his city.
While the previous congressional boundaries split Millcreek into four districts, the map recently adopted by the Legislature puts the suburb into two districts.
Attorneys for the Legislature will begin presenting their defense of the legislative-enacted map Friday morning, with testimony from Trende, Barber and another expert, Jonathan Katz, a social science professor at the California Institute of Technology.
