The US supreme court on Wednesday revived a lawsuit by a Republican congressman in Illinois that challenges a state law allowing mail-in ballots to be counted if they are received after election day.

The lawsuit from Mike Bost was viewed by Donald Trump-aligned conservatives as an avenue to continue attacks on mail-in voting. Bost argued that the Illinois law allowing ballots to be counted up to two weeks after election day if they are postmarked by the deadline unconstitutionally allows an extension of the election period.

Chief Justice John Roberts wrote the 7-2 decision, with two of the court’s liberal justices dissenting.