Mississippi Gov. Tate Reeves set special elections on Nov. 4 to replace outgoing Democratic senators John Horhn, David Jordan and House Rep. Orlando Paden.

The special elections are being held because two Mississippi lawmakers were elected as mayor of their cities, and another resigned midway through his term.

Three leading election integrity groups urged the Supreme Court on Thursday to prohibit states from counting mail-in ballots that arrive after Election Day, warning that the practice violates federal law and undermines public trust in elections.