This fascinating behind the scenes view of mail ballot processing in Kern County, California, includes a description of the important signature verification process that protects against mail-in ballot fraud:
Across the room, under the surveillance cameras that document everything done in the Elections Division, computers loaded up all the images captured by the Relia-Vote.
The computers matched those images and each ballot’s unique serial number to the voter registration file of the voter that mail ballot was assigned to.
Then elections workers began flipping through a computer interface that displayed the ballot’s signature on the screen with the signature the voter used to sign his or her voter registration form.
Elections workers are trained to look for differences in signatures and — if they see them — tag the ballot electronically.
The next time a tagged ballot would go through the sorting machine, it would be kicked out and held back until six elections workers — finishing with Rhea herself — had looked at the signatures.
Ballots without matching signatures are never opened nor counted.
Ballots that clear the signature check are approved for the final sorting runs and opening.