26
ALEXANDER v. SOUTH CAROLINA STATE CONFERENCE
OF THE NAACP
Opinion of the Court
Total Voting Age
Population
Biden Vote
Trump Vote
Net Biden Votes
Biden Vote %
Black Voting Age
Population
Moved from District 1 to District 6
Precinct 1
1,250
Precinct 2
1,250
400
250
150
62%
250
500
600
-100
45%
0
Yes
No
Dr. Ragusa’s model considers only the total number of
Biden votes in its partisanship analysis. J. S. A. 502a. But
legislators aiming to make District 1 a relatively safe Republican seat would be foolish to exclude Precinct 2 merely
because it has more Democratic votes than Precinct 1. Instead, they would look at the net Democratic votes and
would thus remove Precinct 1, not Precinct 2. Although the
use of total votes may be a statistically permissible measure
of partisan lean, it is undoubtedly preferable for an expert
report to rely on net votes when measuring a district’s partisan lean.
The Challengers seek to defend Dr. Ragusa’s report by
suggesting that he followed the same methodology as Professor Stephen Ansolabehere, whose report we blessed in
Cooper, 581 U. S., at 315, but that is wrong. There are important differences between Dr. Ragusa’s methodology and
Professor Ansolabehere’s, 9 and in all events, Professor Ansolabehere’s report played a minor role in Cooper, where the
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9 Two differences in particular stand out. First, while Dr. Ragusa
looked only at Democratic voters to control for partisanship, Professor
Ansolabehere looked at both Democratic and Republican voters. 1 App.
in Cooper v. Harris, O. T. 2016, No. 15–1262, pp. 334–337. Only after
calculating the percentage of black voters moved in each partisan group