Before a plaintiff can claim that actionable vote dilution under Section 2 of the Voting Rights Acts of 1965, the plaintiff must prove the three prerequisites set by the Supreme Court in Thornburg v. Gingles, 478 U.S. 30 (1986). The first of those prerequisites is that a minority group be "sufficiently large and geographically compact to constitute a majority in a single-member district."
At issue in Bartlett was whether North Carolina's District 18 fell within this prerequisite. North Carolina law forbids the Legislature to divide counties when it draws election-district lines. The Legislature, however, disregarded that requirement when it created District 18 in order to ensure that 39.36 percent of the voting-age population of the district would remain African-American, as opposed to the 35.33 percent it would be absent dividing the counties.
The core question presented for the Court was whether the first requirement of Gingles is met by proving that the minority group, while not large enough to constitute a majority in the particular district, could join forces with other groups to elect the candidate of the minority group's choosing. The Court answered that question no, holding that only when a geographically-compact group of minority voters could form an actual majority in a single-member district is the first requirement of Gingles satisfied. Thus, Section 2 of the Voting Rights Act did not require North Carolina to create District 18 in the way that it did.
No opinion commanded a majority of the Court. Justice Kennedy delivered an opinion in which Chief Justice Roberts and Justice Alito joined. Justice Thomas filed an opinion concurring in the judgment, in which Justice Scalia joined. Justice Souter filed a dissenting opinion in which Justices Stevens, Ginsburg and Breyer joined.