28
ALEXANDER v. SOUTH CAROLINA STATE CONFERENCE
OF THE NAACP
Opinion of the Court
neighbors were moved too.
This defect alone is sufficient to preclude reliance on Dr.
Liu’s report, but that report exhibited another flaw: it used
inferior data to measure a district’s partisan tilt. While the
State used voting data from the 2020 Presidential election,
Dr. Liu relied on data from the 2018 gubernatorial primaries. Data from that gubernatorial primary is less informative because far fewer voters turn out for off-cycle gubernatorial primary elections. The numbers prove the point. In
the 2018 elections, a total of about 610,000 votes were cast
across both primaries; in the 2020 Presidential election, by
contrast, a total of 2.5 million votes were cast. 10 Because
Dr. Liu examined only a small, highly non-random sample
of the regular voting electorate, we cannot say that the
same results would hold true if he had applied his methodology to the State’s 2020 data.
Dr. Moon Duchin. Dr. Moon Duchin, the final expert put
forward by the Challengers, provided a report assessing
whether the Enacted Plan “cracks” black voters among multiple districts in a way that produced “discernible vote dilution.” J. S. A. Supp. 127a. After finding that the Enacted
Plan diluted the black vote, Dr. Duchin concluded that it is
“not plausible” that the dilution was a mere “side effect of
partisan concerns.” Id., at 175a.
Neither the District Court nor the Challengers cite Dr.
Duchin’s report to support the racial-predominance finding,
and that is for a good reason. Like Dr. Imai’s report, various parts of Dr. Duchin’s report did not account for partisanship or core retention. App. 102–103. Moreover, Dr.
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10 See N. Y. Times, South Carolina Governor Primary Election Results
(Nov. 3, 2020), https://www.nytimes.com/elections/results/south-carolinagovernor-primary-election; N. Y. Times, South Carolina Presidential
Election Results (Nov. 3, 2020), https://www.nytimes.com/interactive/
2020/11/03/us/elections/results-south-carolina-president.html; see also
App. 135 (testimony of Baodong Liu) (noting that Presidential election
years “usually ha[ve] a very high level of voter turnout”).