First let me make it clear that I have absolutely no doubt that Trump lost the 2020 election and that Biden won. These purely are hypothetical questions.
Scenario #1: What if it was absolutely proven beyond all doubt that through some sort of error the vote was not counted correctly and Trump was the actual winner. What would happen next? As far as I know we have no laws that would tell us what to do in this situation.
Scenario #2: What if it proven that Biden and the democrats did something illegal that gave Biden enough votes to win (say by tampering with the voting machines, or altering data, or giving mail-in ballots to hamsters, it doesn’t matter). What would happen next? Obviously Biden (and possibly Harris) would be impeached but then what?
In scenario 1 I don’t think anything could be done. The electors were appointed and they cast their ballots. These were accepted by Congress. Those are the only votes that count.
Scenario 2. I don’t see how Trump could be made President. If Biden and Harris are both impeached and removed, then the Speaker (presumably Pelosi depending on the timing) becomes President.
Once the Electors are certified, they are the people who legally choose the President and Vice President. There is no legal basis for declaring their selection invalid. If they had, for some unfathomable reason, chosen to vote for Martin Sheen and Julia-Louise Dreyfus on December 14, 2020, then Sheen and Dreyfus would have been legally elected.
As to the second scenario, I think we can take it as a given that “the Democrats” didn’t do something illegal. I’m a Democrat and I didn’t break any laws. So the question is what we would do if a group of Democrats had broken the election laws and caused Biden and Harris’ election.
If Biden and Harris were involved, they should be impeached and removed from office. And then charged for their crimes.
If Biden and Harris were not involved and were the innocent beneficiaries of criminal acts they were unaware of, it becomes a lot murkier. I don’t feel a President or Vice President can be impeached for crimes committed by other people. Should they feel morally obligated to resign? I don’t know. I lean towards saying no but I’m open to debate on this point.
I don’t see any scenario where Trump resumes the Presidency, other than winning a future election.
It would be like a sports outcome: Even if the officials made wrong calls, it’s essentially unheard-of for a sports league to reverse the outcome of a game. They just say, “Well, that was a wrong one” and then put in necessary reforms to prevent it from happening again, but don’t reverse the outcome.
So if Biden were indeed proven to have been the wrongful winner, he still remains president. There might be a an apology issued to Trump, but that’s all.
And even if Biden were proven to have committed fraud, it all comes down to whether there is a two-thirds majority in the Senate to eject him from office, and there almost certainly won’t be. You can’t get 17 Democrats to go along.