While the Supreme Court was considering the case, much more slowly than expected, the lower court that had invalidated the map said it could be used for this year’s election.

The justices’ ruling will therefore have no immediate impact in South Carolina, but it sets the rules of the road for future redistricting efforts, making it easier for maps to be drawn that disfavor Black voters as long as the map-makers can show they are using race as a proxy for political affiliation.