Trump claims fraud in the election and the media screams for proof. Fair enough, to a point. Laws guarantee Republican and Democratic representatives be allowed to observe the count, and yet they were denied in many locations. Even after the courts, as in Pennsylvania, ordered compliance they were denied entry.
As for evidence of fraud, once the ballot is removed from the security envelope the evidence is destroyed. Without observers, there is no way to check postmarks or signatures. If you are bent on fraud that is the entire point of denying observers.
As for the overall process of mass-mailed ballots, it is obvious that ballots are mailed to people who have passed away and that family members are likely to receive the ballot and vote. Several states did away with signature checks so the ballots would sail through. Likewise, people who have moved out of state and had mail forwarded to them very likely voted illegally in two states.
And with millions of ballots printed and floating around, you cannot tell me that ballots cannot disappear and then return en masse on the day of counting. Only with in-person voting can fraud be largely prevented. Identifications must be checked against registration logs, signatures checked, and logs of completed and unused ballots must be kept and audited. Only then will I have confidence in future elections.
In my opinion, recent changes in many states are designed to allow fraud to occur.