 A provision in the Civil Rights Act's legislation President Lyndon B. Johnson signed into law six decades ago says a person's right to vote cannot be denied because of an error or omission that is, quote, not material in determining if a person is eligible to vote. What's known as the materiality provision has been cited in a recent case about whether to count mail-in ballots that arrive on time in Pennsylvania, but with missing or incorrect dates handwritten by the voter on the outer envelope.