If you have a Democracy/Republic where there are plenty of statistically impossible to refute evidence of election fraud, your only option is to "go with it to the judges".
Now let's say the judges give you the finger, because, well, because that is what they give you… what now?
Well, first of all you're no longer having a Republic.
If you have any doubt, check history and see that many times democracies became non-democracies. The probability this will happen here is greater than million times the probability there wasn't election fraud. And I'm talking election fraud that changed the results of the elected president.
So what's left? If you agree with the content so far, and you're the president, you have to decide if you trust your judgment enough or not.
But you're already running for presidency – you just asked everyone in your country to vote for you, so you can get the majority for a win. That is identical to trusting your judgment in such matters.
Last thing: There can still be reasons for Trump not to do it. E.g. maybe he's afraid to go to jail if such a move will fail. Yet, all such reasons are personal. It's fair enough if he'll choose one, but it's important that we all know the difference and where we stand.
If somehow that miracle will happen (Short military rule), we'll need to build our republic very differently. The way it is now can't work for the current society with the current technology. You threat to smear a judge with racism, alleged sexual abuse, misogyny, whatever… and he's in your pocket.
He probably already was; you just didn't want to take any chance that he's one of those few who doesn't yet have enough fear to obey automatically.
One thing that is not just moral bankruptcy, but also pure evidence of deep and successful brain wash, is the fact that we don't use those same tactics and tools the left uses, and obviously works with enormous efficiency. E.g. wouldn't you prefer that those unfortunate leverages on judges – as long as they exist – will be used for your family and country, than against them?
But I guess that is a matter for another day. (https://write.as/vaela/using-the-left-weapons-against-them-quickly-and-swiftly)
We are so past the point of action.