# Thornburg v. Gingles The decision that built the test every modern Voting Rights Act case still runs through. Decided June 30, 1986 — unanimous in result, with a fractured opinion on the underlying analysis — *Thornburg v. Gingles* established the framework for proving vote dilution under Section 2 of the [[Voting Rights Act of 1965]], as amended in 1982 to make discriminatory *results*, not just discriminatory *intent*, actionable. The case arose from North Carolina multimember legislative districts that diluted the voting strength of Black citizens. ## The Gingles Test The Court held that to make out a Section 2 vote-dilution claim, plaintiffs must satisfy three preconditions: (1) the minority group is sufficiently large and geographically compact to constitute a majority in a single-member district; (2) the minority group is politically cohesive; and (3) the majority votes sufficiently as a bloc to usually defeat the minority's preferred candidate. Crucially, the Court confirmed that under the 1982 amendments plaintiffs need not prove discriminatory purpose — proof of discriminatory results suffices. ## Significance The three-prong *Gingles* test is the doctrinal spine of redistricting law and the reason majority-minority districts exist. It underlies the entire Voting Rights line the vault tracks: it set the rules that [[Shaw v. Reno]] (1993) then put in tension with the Equal Protection Clause, that survived in [[Allen v. Milligan]] (2023), and that [[Louisiana v. Callais]] (2026) rewrote by demanding proof of intent — effectively unwinding the 1982 results test that *Gingles* implemented. To understand what *Callais* dismantled, you have to start with what *Gingles* built. ## See Also - [[Voting Rights Act of 1965]] — The statute *Gingles* operationalized - [[Shaw v. Reno]] — The Equal Protection counter-pressure on *Gingles* districts - [[Allen v. Milligan]] — Where the *Gingles* framework was upheld - [[Louisiana v. Callais]] — Where it was rewritten to require intent - [[Packing and Cracking]] — the two elementary operations of district manipulation, and why they are mathematically complementary - [[The Mathematics of Redistricting]] — how district maps became a computational optimization problem, and what mathematics can and cannot establish about them