18
RUCHO v. COMMON CAUSE
KAGAN, J., dissenting
too far. Consider again Justice Kennedy’s hypothetical of
mapmakers who set out to maximally burden (i.e., make
count for as little as possible) the votes going to a rival
party. See supra, at 12. Does the majority really think
that goal is permissible? But why even bother with hypotheticals? Just consider the purposes here. It cannot be
permissible and thus irrelevant, as the majority claims,
that state officials have as their purpose the kind of grotesquely gerrymandered map that, according to all this
Court has ever said, violates the Constitution. See supra,
at 13.
On to the second step of the analysis, where the plaintiffs must prove that the districting plan substantially
dilutes their votes. The majority fails to discuss most of
the evidence the District Courts relied on to find that the
plaintiffs had done so. See ante, at 23–24. But that evidence—particularly from North Carolina—is the key to
understanding both the problem these cases present and
the solution to it they offer. The evidence reveals just how
bad the two gerrymanders were (in case you had any
doubts). And it shows how the same technologies and data
that today facilitate extreme partisan gerrymanders also
enable courts to discover them, by exposing just how much
they dilute votes. See Vieth, 541 U. S., at 312–313 (opinion of Kennedy, J.) (predicting that development).
Consider the sort of evidence used in North Carolina
first. There, the plaintiffs demonstrated the districting
plan’s effects mostly by relying on what might be called
the “extreme outlier approach.” (Here’s a spoiler: the
State’s plan was one.) The approach—which also has
recently been used in Michigan and Ohio litigation—
begins by using advanced computing technology to randomly generate a large collection of districting plans that
incorporate the State’s physical and political geography
and meet its declared districting criteria, except for partisan gain. For each of those maps, the method then uses