Vote-By-Mail fails most of the safeguards against election fraud: (1) There should be a valid reason for not being able to vote in person at the polling station. (2) Photo ID verification is not possible (despite the requirement to show photo ID for almost everything else). (3) Secrecy and confidentiality are compromised, allowing undue influence and coercion to be applied to voters, and facilitating vote buying. (4) Signature verification is made more complicated. (5) Chain-of-custody is difficult to maintain with Vote-By-Mail. (6) Vote-By-Mail facilitates ballot harvesting by third parties, who collect mail-in ballots from unrelated voters.
Vote-By-Mail turns the United States Postal Service into the largest precinct in the country, with no oversight by poll-watchers. In addition: (1) Requests for Vote-By-Mail should be required before each election cycle, and should not be maintained in perpetuity. (2) Mail-in ballots should contain a security question that must be answered correctly. (3) Mail-in ballots should be required to be received by the election officials not later than election day.