[9YearLurker]

As I understand it, fraud nullifies safe harbor protections, plus it us ultimately up to Congress and Pence, of all people, to determine if they accept designated electors.

[Boise3981]

As I understand it, fraud nullifies safe harbor protections, plus it us ultimately up to Congress and Pence, of all people, to determine if they accept designated electors.

You understand incorrectly... at least mostly.

Fraud may nullify the result, but it's up to the states to say whether there has been fraud. And so far all the states in question say there was not. And with safe harbor hitting, the chance to prove fraud in court has passed.

Congress can then evaluate whether they accept designated electors but, according to the rules passed by Congress in 1877, to nullify a slate of electors you need agreement from both houses of Congress. Clearly, the Dem House isn't going to agree to nullify any Biden state. It's doubtful even the Senate would agree to that. So the slate of electors presented by the states will stand.

Trump will get no relief from the federal courts. His only chance stems from the state level - probably state legislatures.