The Dems promote mail votes because there is a Covid19 pandemic and working people don't have to queue up for hours on a week day. No evidence of voter fraud despite multiple investigations. Trump knows he will be trounced in a fair election. All he can do is cheat or scream "foul".
"According to the Brennan Center for Justice at New York University, there is no evidence that mail balloting increases electoral fraud as there are several anti-fraud protections built into the process designed to make it difficult to impersonate voters or steal ballots. These provisions include requiring people requesting absentee ballots to be registered voters, mailing ballots to the official address listed on voter registration rolls, requiring voter signatures on the external envelope, and having election authorities make sure the ballot came from the address of an actual voter. If a ballot appears questionable, some states use a signature matching technique to verify the signature of the voter."
