The Supreme Court’s ruling that two North Carolina congressional districts relied too heavily on race should give voting-rights advocates a potent tool to fight other electoral maps drawn to give Republicans an advantage in the state.

The justices agreed Monday with a federal court that had struck down two congressional districts as illegally race-based. Because those districts were already redrawn for the 2016 election, the ruling doesn’t require immediate changes from North Carolina. But it looms large in other battles unfolding over voting districts there and elsewhere.