Cite as: 602 U. S. ____ (2024)
27
Opinion of the Court
plaintiffs could also point to direct evidence. Here, by contrast, once the District Court’s other circumstantial findings are set aside, the Challengers must rest their entire
case on these expert reports. Dr. Ragusa’s report, on its
own, cannot prove that District 1’s lines are “unexplainable
on grounds other than race.” Shaw I, 509 U. S., at 644 (internal quotation marks omitted).
Dr. Baodong Liu. Dr. Baodong Liu, another of the Challengers’ experts, submitted a report that purported to show
that race rather than politics explains District 1’s design.
Although the District Court did not cite Dr. Liu’s report, the
Challengers contend that it bolsters the District Court’s
findings. Tr. of Oral Arg. 86–87. But Dr. Liu’s methodology
was plainly flawed.
First, his methodology, like Dr. Ragusa’s, failed to account for contiguity and compactness. Dr. Liu examined all
voters living within the county envelope for District 1 of the
Enacted Plan to see which voters were more likely to have
been excluded. His analysis suggested that black Democrats were more likely to have been excluded than white
Democrats.
This methodology was highly unrealistic because it
treated each voter as an independent unit that South Carolina could include or exclude from District 1. No mapmaker who respects contiguity and compactness could take
such an approach. For example, a mapmaker could not assign a black Republican to one district while moving a black
Democrat who lives in the same apartment building to another district. To accurately reflect the districting process,
an analysis would have to pay attention to whether a voter’s
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did Professor Ansolabehere conclude that “race, and not party, had a disproportionate effect on the configuration of ” the congressional districts.
Id., at 337. Second, Professor Ansolabehere’s analysis operated at the
voter level. Id., at 313–314. That enabled him to compare the demographics of the moved voters to the general population in a way that
Dr. Ragusa’s precinct-level analysis cannot.