The 5-4 decision, with conservative justices in the majority, could make it harder for Democrats in the South to draw friendly electoral boundaries.
Democrats have sought to establish districts in which blacks, though not a majority, still were numerous enough to determine the outcome of elections with the help of small numbers of like-minded white voters. Those districts could be challenged under Monday’s decision.
Civil rights groups said the ruling could dilute the voting strength of minorities by resulting in more districts with minorities constituting less than half the population.
The ruling involved a North Carolina House of Representatives district where black voters made up less than half of the population. With limited support from white voters, a black candidate has been elected to represent the district in the past.
In 2007, the North Carolina Supreme Court struck down the district, saying the Voting Rights Act applies only to districts with a numerical majority of minority voters.
The Supreme Court upheld the state court’s decision.
Justices declined to expand protections of the landmark civil rights law to apply to districts where the minority population is less than 50 percent of the total, but strong enough to effectively determine the outcome of elections.
Announcing the court’s judgment, Justice Anthony Kennedy said requiring minorities to represent more than half the population “draws clear lines for courts and legislatures alike. The same cannot be said of a less exacting standard,” according to the Associated Press.
Chief Justice John Roberts and Justice Samuel Alito signed onto Kennedy’s opinion. Justices Antonin Scalia and Clarence Thomas agreed with the outcome of the case.
The four liberal justices dissented. A district like the one in North Carolina should be protected by federal law “so long as a cohesive minority population is large enough to elect its chosen candidate when combined with a reliable number of crossover voters from an otherwise polarized majority,” Justice David Souter wrote for himself and Justices Stephen Breyer, Ruth Bader Ginsburg and John Paul Stevens.
Souter wrote that Kennedy’s opinion “has done all it can to force the states to perpetuate racially concentrated districts, the quintessential manifestations of race consciousness in American politics.”
Ginsburg wrote that Kennedy’s interpretation of the law “is difficult to fathom” and added, “Today’s decision returns the ball to Congress’s court.” She urged lawmakers to clarify the appropriate reading of the law.
The court will hear arguments in April on another important voting rights case. It involves the law’s provision that requires states or local governments with histories of racial discrimination to get federal approval before making any changes in election procedures.
In a separate election-related case, the court let stand an appeals court decision that invalidated state laws regulating the ways independent presidential candidates can get on state ballots.
Arizona, joined by 13 other states, asked the court to hear its challenge to a ruling throwing out its residency requirement for petition circulators and a June deadline for submitting signatures for independent candidates in the November presidential elections.
Independent presidential candidate Ralph Nader sued and won a favorable ruling from the 9th U.S. Circuit Court of Appeals in San Francisco.
Also on Monday, the court turned away pleas by New York City and gun violence victims to hold the firearms industry responsible for selling guns that could end up in illegal markets.
The justices’ decision ends lawsuits first filed in 2000. The city’s lawsuit asked for no monetary damages. It had sought a court order for gun makers to more closely monitor those dealers who frequently sell guns later used to commit crimes.