A federal district court had ruled that in light of the COVID-19 pandemic that requirement could result in the disenfranchisement of voters and issued an injunction lifting the rule ahead of Election Day.
Chief Justice John Roberts wrote in the order that ballots received within the next two days would be exempt, but after that the witness requirement would be back in effect in South Carolina pending the outcome of the ongoing legal case on the merits.
The Supreme Court's action effectively means absentee ballots mailed from now to Election Day in South Carolina will almost certainly need a witness signature to count. Some advocates have warned those signatures can be especially difficult for elderly voters to obtain at a time when all Americans are being advised to limit social contact because of the virus.
The decision continues a trend by the Roberts court to allow state officials to determine their own election policies and limit unnecessary judicial interference so close to Election Day.