The changes are almost certain to cause some votes to be tossed. They come at a time when President Trump is promoting false claims of widespread fraud in mail voting.
A new rule in North Carolina requires officials to disqualify ballots with an unsealed envelope and limits who can drop off mail ballots on behalf of another voter.
A federal judge has temporarily blocked a Postal Service rule that could impede millions of mail voters. The Trump administration has asked the Supreme Court to weigh in.