8
ALEXANDER v. SOUTH CAROLINA STATE CONFERENCE
OF THE NAACP
THOMAS, J., concurring in part
equipped to evaluate whether plaintiffs succeed in disentangling race and politics.
As the Court observes, roughly 90% of black voters in
South Carolina supported the Democratic candidate in the
last Presidential election. Ante, at 4, and n. 2. When nearly
all black voters support Democrats, an effort to strategically sort Democratic voters can be indistinguishable from
an effort to strategically sort black voters. In this case, all
Democratic-leaning maps presented during the districting
process featured a black share of the voting-age population
of 21% or higher, and all Republican-leaning maps featured
a black voter share of 17% or lower. Ante, at 15. The dispute in this case therefore focuses on whether that correlation reflected a racial purpose, or merely reflected the result
of a political purpose.
The majority’s reasoning highlights the difficulties inherent in disentangling race and politics. Its explanation of
why the expert evidence was insufficient does not rest on
the application of legal principles, but on the likely errors it
finds in the experts’ statistical models after a “foray into the
minutiae of the record.” Cromartie, 532 U. S., at 262 (opinion of THOMAS, J.). The majority discounts four separate
expert reports based on methodological concerns. One report is insufficient because it fails to model partisanship.
Ante, at 19–21. Another “carries less weight” because it
measures partisanship through the wrong statistical
method. Ante, at 25. And, another cannot be relied upon
because it measures partisanship with the wrong election
data. Ante, at 26–27. The dissent accuses the Court of
“play[ing] armchair statistician.” Post, at 31 (opinion of
KAGAN, J.). But, the dissent’s defense of the expert reports
includes an exercise in armchair cartography. The dissent
justifies the experts’ assumption that the legislature could
move any precinct in District 1 to District 6 by explaining
that District 1 is thin, coastal, and shares a long border with
District 6. Post, at 28–30. It supports its hunch with two