The Supreme Court's 6-3 ruling in Louisiana v. Callais effectively gutted a key provision of the Voting Rights Act of 1965, making it nearly impossible for voters to challenge maps that dilute minority voting power. Justice Samuel Alito wrote the majority opinion on behalf of all six Republican appointees, "updating" a four-part test from a 1986 decision.

Chief Justice John Roberts's decades-long campaign against the law finally reached its culmination. As far back as 1982, as a young Reagan administration lawyer, he opposed expanding the Act to address practices with discriminatory results. The ruling requires plaintiffs to focus on evidence of "present-day intentional racial discrimination regarding voting" — a much higher bar.

Legal scholars called the decision a "disaster," a "catastrophe" and "the worst ruling in a century." Harvard law professor Nicholas Stephanopoulos wrote it would cause "the biggest reduction in the number of minority legislators since at least the end of Reconstruction." A separate case from North Dakota, currently on the court's docket, could deal another blow by barring private plaintiffs from suing under the Act — 93 percent of such challenges since 1982 were brought by private parties.