80 million Americans may vote by mail in this election. Here's how most states verify their identities.

That surge has caused renewed interest in the way the majority of states verify the identities of mail-in voters — via their signatures.In the process of “signature verification,” election officials compare a voter’s signature on a ballot’s security envelope with a past signature on file, often from the state department of motor vehicles or a voter registration form. Because all of those signatures are then used to decide whether the signature that's actually on the ballot was the one of the voter that the county has on file.”Persily co-launched the Stanford/MIT Healthy Elections Project, which recently published a report called “Behind the Scenes of Mail Voting: The Rules and Procedures of Signature Verification in the 2020 General Election.” The report points out that increased mail voting could lead to an increase in the associated risk that ballots will be rejected due to mismatch. It also says many states have been prompted to clarify their signature matching standards and extend opportunities for voters to fix discrepancies.According to the report, at least 31 states and the District of Columbia require election officials to compare the signature on a mail ballot’s security envelope with a signature on file as part of their verification processes.