Cite as: 588 U. S. ____ (2019) 21 KAGAN, J., dissenting Republicans (2014). In what was once a party stronghold, Republicans now have little or no chance to elect their preferred candidate. The District Court thus found that the gerrymandered Maryland map substantially dilutes Republicans’ votes. See Lamone, 348 F. Supp. 3d, at 519– 520. The majority claims all these findings are mere “prognostications” about the future, in which no one “can have any confidence.” Ante, at 23 (internal quotation marks omitted). But the courts below did not gaze into crystal balls, as the majority tries to suggest. Their findings about these gerrymanders’ effects on voters—both in the past and predictably in the future—were evidence-based, data-based, statistics-based. Knowledge-based, one might say. The courts did what anyone would want a decisionmaker to do when so much hangs in the balance. They looked hard at the facts, and they went where the facts led them. They availed themselves of all the information that mapmakers (like Hofeller and Hawkins) and politicians (like Lewis and O’Malley) work so hard to amass and then use to make every districting decision. They refused to content themselves with unsupported and out-of-date musings about the unpredictability of the American voter. See ante, at 24–25; but see Brief for Political Science Professors as Amici Curiae 14–20 (citing chapter and verse to the contrary). They did not bet America’s future—as today the majority does—on the idea that maps constructed with so much expertise and care to make electoral outcomes impervious to voting would somehow or other come apart. They looked at the evidence—at the facts about how these districts operated— and they could reach only one conclusion. By substantially diluting the votes of citizens favoring their rivals, the politicians of one party had succeeded in entrenching themselves in office. They had beat democracy.