Here is one way they do it.
Just one of the ways, mail voting gives the rats multiple ways to cheat. For example toss just enough ballots from all the right zip codes and you tip 3-4% of the overall votes to the rats. That would have more then enough to take Trump out in 16.
The Democrat states will all have vote-by-mail before November. That negates any DJT majorities that some of these states do have. Vote-by-mail and the major cities, all Democrat controlled, in each state reporting their vote totals last will lock the election for the Democrats. The only question will be can they extend it to the Senate and the House? I think they are salivating at the thought of a very possible 40+ state sweep in November.